SIP vs. Skype, Making the "Open" Choice

techie34290 writes "If you were to make the choice between SIP and Skype for Linux, which one would you go for? Matt Hartley from MadPenguin.org says to opt for SIP. Why? "One tidbit of information that most people are not likely aware of is that when you install the Skype client, it will drain system resources by running as a supernode from time to time. Granted, this is not always the case; however, the very idea of my PC having its resources tied up for someone else's phone call is frankly maddening to me."

Comments

I Choose Skype

[Anonymous Coward]

Cause I've cybered there with women I met from SWG back in the day K.

Isn't that the point?

[dizzoug]

The sacrifice you make to have a 'free' phone service is your system resources. Without donating your clock cyles, you would have to pay skype to use servers that they would otherwise have to provide. And yes, if your system can handle it, it will act as a supernode from time to time. It is your choice, but very few things are truly free.

Re:Isn't that the point?

[FooAtWFU]

I seem to recall this being the reason that a number of locations were reported as considering banning Skype in a recent Slashdot story.

Re:Isn't that the point?

[Greyfox]

Yah. Something kind of similar with sip (or IAX) is fwdout. You share your landline for local calls in return for use of the network.

Of course these days it's pretty rare that the person you're calling does not also have a computer, so you could make a free point to point call with sip just as easily. You just need to know the IP address of the person you're calling, or they can get a free number for internet calls from Free World Dialup.

Re:Isn't that the point?

[Vihai]

No, it isn't. No wonder there is no "SIP" server, managed by a "SIP" company.

SIP is a technology while Skype is a service, provided by a single company with a proprietary technology.

The difference is absolute.

You could provide the same exact service Skype is providing with SIP. Did you ask to yourself why there is no such service? Because it would be much harder to lock your customers in with SIP. SIP is already peer-to-peer for what concerns audio streams.

Re:Isn't that the point?

[Anonymous Coward]

You could list your number with e164.org and use that to make calls, iirc ekiga can use enum lookups (DNS queries) to get routing information so you don't need to know IPs etc...

Re:Isn't that the point?

[Fordiman]

Actually, the only reason this is done is that, for two computers without the ability to open up a listening port to Internet, they have trouble contacting one another. So, Skype uses one of its members as a through-way for a call. Calls done in this manner are reduced in quality to reduce the third-party's overhead (since you're essentially leeching off another human to do it).

It would be very nice to find a way to make a TCP/IP connection without having a listening port. I believe it could be done, still using the third party for setting up the connection, but using a spoof of some nature.

A possible way is: Caller (C) requests a connection via the Skype Network (SN) to Reciever (R). R is connected to SN, but has no incoming connection capabilities, so SN requests a transitional connection from a third party (T). C and R both call T. R tells T which local port its connection is on. T spoofs C, telling C that its IP address and port are those of T. T also spoofs R, telling it that its IP address is that of C, connecting on R's port(R effectively becomes the server, the router's outgoing port becoming the incoming port). R and C, knowing this will happen, do all the syn/ack stuff manually.

I'm not well enough versed in TCP/IP to do this (or even say whether it can be done), but perhaps someone is.

Re:Isn't that the point?

[x-router]

There are SIP providers that do!

I don't use skype so I can't say 100% that my SIP provider matches what they offer but I use http://voiptalk.co.uk./

I have some SIP handsets that plug directly into my network anywhere in the house. (that means no PC needed)

I get free calls to any other SIP user, I have a real paid for land line number(several), answer phones etc etc etc. All the usefull stuff that skype does and more. I don't have a real world phone anymore and never had any problems so I would say that there are people offering SIP services as good as if not better than skype out there its just not everyone knows about them because it's skype hype atm.

The fact is all the major telcoms houses are working with SIP or various open protos and at some point skype will have to let others in to play or be forgotten.

Re:Isn't that the point?

[CharlieHedlin]

You are right and wrong. Skype is both a service and a technology.

Re:Isn't that the point?

[Anonymous Coward]

Easier: if the router follows the rules about port binding, the two ends do a connect() to each other at the same time.

The rule used by NAT routers for this is: when only destination IP changes, use same port mapping.

Re:Isn't that the point?

[Sylver Dragon]

I can confirm that this is occuring. I work at a University, and while they do not, technically, ban Skype outright, they might as well. The reason for this is that Skype likes to put computers on our network into supernode mode (considering the bandwidth here, I understand why it happens). The problem is that it starts eating bandwidth like mad, and reduces bandwidth available for other users. So, in order to combat the bandwidth hogging, Skype traffic is throttled at the firewall; it is still allowed to connect and use some bandwidth, but you can forget video conferencing. And before I get any of the "but, but, but...student's rights" type posts: we are a private university, i.e. no public funds; the students have the right to go elsewhere if they don't like it.
Actually, this is a rather timely article, as I am working on setting up a video conferencing room and need to find good free/cheap options.

Re:Isn't that the point?

[Fordiman]

Well, as I understand it, Skype's pretty derned smart. I do believe it checks all reasonable avenues of connection before it resorts to third party connection.

Meanwhile, a program can't expect the router to follow port-binding rules, necessarily - though, it can always check.

Re:Isn't that the point?

[Anonymous Coward]

... we are a private university, i.e. no public funds; ...

So none of your students get financial aid? no loans guaranteed by a gov. agency?

Re:Isn't that the point?

[STFS]

Did you ask to yourself why there is no such service? Actually there is: http://openwengo.com/

Wengos application is GPL and it uses SIP as its protocol. Behind it, there's a french phone company I believe which seems to think that this may somehow pay off for them (I don't know much more about their business model though).

Re:Isn't that the point?

[phatmonkey]

Yes there is.

Re:Isn't that the point?

[Rodness]

I've done a lot of research on Skype lately. If you're running as a supernode, it only uses about 6k of bandwidth up and down, it doesn't monopolize your network connection.

And if you want to make sure you'll never be a supernode, just make sure you're behind a firewall/NAT. The criteria for being a supernode are fast processor, available memory, and fast UNFIREWALLED connection. It's very easy to make sure you're not a supernode by using a firewall. It's really not that big a deal, and certainly not worth being up in arms against.

If you want to be pissed off about Skype, there's bigger things to worry about. Among those:

Closed protocol
RC4 obfuscation layer so that we can't see what's being transmitted
Binary with anti-debugging techniques so we can't see what it's doing
And so forth...

Re:Isn't that the point?

[towsonu2003]

we are a private university, i.e. no public funds; the students have the right to go elsewhere if they don't like it.

that's a bullshit answer. changing universities is very different from changing (say) your window manager. Your argument may hold true for a window manager, but it fails for something as real-life-hard & expensive as changing one's university.

moreover, I'd expect an employee of a private university to respect his/her students. Who's paying your wages? Oh yes, you got it right and tight, your students are your employer. So suck it up & respect them.

Re:Isn't that the point?

[papaia]

... So, in order to combat the bandwidth hogging, Skype traffic is throttled at the firewall ...

... and how exactly are you doing "traffic throttling" at the firewall? I have been researching methodologies for identifying Skype traffic for a while now, and have not been able to narrow it down to a controllable behavior (i.e. specific UDP port, specific pattern/data payload deduced from call establishment signaling, etc.)

Re:Isn't that the point?

[shokk]

Someone changing universities because they can't use Skype doesn't have their head screwed on straight.

Re:Isn't that the point?

[Anonymous Coward]

Disclaimer: I work for a large network equipment vendor and have spent some time decoding skype.

Skype can be blocked with NBAR if you have Cisco equipment - "match protocol skype" was introduced in IOS version 12.4(4)T.

Skype is very difficult to block, it uses very sneaky tricks and tries to act very much like web traffic, we will not be releasing the PDLM for skype as it's faily smart how we identify the traffic and given Skype's track record, it will make their life easier.

It certainly isn't as easy as just firewall filters and the protocol was obviously designed with circumventing filters in mind. I won't go as far as calling the parent post a liar but I'm skeptical that no mention of this issues of blocking Skype were rasied with his comments.

Re:Isn't that the point?

[Anonymous Coward]

Yep, I concur.

We are also a vendor that does similar stuff, and I can tell you that skype is very non-trivial to detect. ie: you don't just setup a linux firewall and block it.

Re:Isn't that the point?

[edschurr]

His employer is the university. The students are customers.

Re:Isn't that the point?

[Anonymous Coward]

"Actually, this is a rather timely article, as I am working on setting up a video conferencing room and need to find good free/cheap options."

Access Grid.

www-unix.mcs.anl.gov/fl/research/accessgrid

Re:Isn't that the point?

[Rogerborg]

No. Next question.

Re:Isn't that the point?

[Greyfox]

Aah yes good point, I neglected to mention e164.org. e164.org lets you register your phone number and associate it with a voip address. They also have a handy little script that lets Asterisk search e164 to see if it can find a match for the phone number. If it finds one it can route the call over the Internet.

My asterisk setup first checks to see if it's a free local call (800, 303 or 911) and routes over the landline if it is.

Then it checks my local set of DUNDI peers to see if any of THEM know where the number I'm calling is. If they do, I go that route.

Then it checks various enum sites like e164.org to see if they know anthing about the number.

If all else fails it routes the call out to my voip provider.

This allows me to make free point to point calls if routes exist that I can use. Though my voip provider is flat-rate I try to keep load off their network as much as possible.

Re:Isn't that the point?

[Anonymous Coward]

sure you do... A simple firewall indeed. Block all ports or disable the all jacks... Granted, everything else dies, but you have have stopped the Skype traffic. :)

Re:Isn't that the point?

[Knetzar]

You're right, they should chage each student more so that the students have the right to use the internet any way they wish.

Re:Isn't that the point?

[sjames]

if it's burning THAT much bandwidth, they have few choices. They can Ban it, limit it, or charge all students more for their net connection to accomodate a few. I'd say they're being quite reasonable by choosing the middle option.

Re:Isn't that the point?

[Sylver Dragon]

Unfortunatly, I do not have any involvement in this, so I'm not familiar with how it was done (My position is directly linked to a research institute inside the University, I'm sort of the red-headed step child of the IT department). I'm just the unlucky sap who has to inform people about it when they hit it.

Re:Isn't that the point?

[towsonu2003]

I am not surprised a bit that geeks of Slashdot (who are employed to provide services to non-geeks) are not pleased a bit with the notion that the people they provide services to are *in fact* their employer, who are to be respected.

your job is to provide services without causing any major inconveniences (like asking them to _change universities_) to the people you provide your services. Those students, especially if you're a private university employee, are your boss. And you're their employees. Get used to it.

Re:Isn't that the point?

[Achromatic1978]

Uhh, no. So wrong it's not funny. The university is the employer. They provide a service - education, and related ancillary tasks. To whom do they provide this? Students, who pay for it. Ergo, students are /customers/, /not/ /employers/.

For every situation, there's often a simple explanation. Yours just happened to be wrong.

When you're buying a computer from Best Buy, do you start ordering the staff around and tell them to "get used to it, you're the boss"?

Re:Isn't that the point?

[Fordiman]

Thanks, I don't mind being shot down. But could you explain the technical reasons why it couldn't be made to work?

Re:Isn't that the point?

[jesup]

Tricks like that only work if you can predict the external port number to tell the other person to use. A third-party site can do this (though you should use STUN instead of Skype) - but only if your NAT isn't a fully-symmetric NAT. (There are 4 main types of NAT, one of which is symmetric, where the port number to communicate to host A is different than the port number when communicating to host B, and there's no way to know.)

The alternative when behind such a nat is to use a relay (such as RTP-Relay, a TURN server, or what Skype does), or to tell the NAT to open a port for you (such as via UPnP), or statically configure a port-forward in the NAT.

Re:Isn't that the point?

[Anonymous Coward]

what would it matter if they did?

Re:Isn't that the point?

[aichpvee]

Exactly. If he were at a public university the students would be the employers AND the customers.

Re:Isn't that the point?

[sjames]

Where do you get that? Bandwidth costs money. Students usually aren't swimming in money. So, it's better to limit bandwidth on a single app than to raise prices.

Re:Isn't that the point?

[SmokedS]

The primary purpose of supernodes is to allow NATed or otherwise firewalled skype clients to communicate with each other. In other words, this is one of the many problems for which the major part of the root cause is the lack of IPv4 addresses. It's about time IPv6 was rolled out already. This will largely become a non problem once that happens.

Re:Isn't that the point?

[Anonymous Coward]

So, let's recap here:

MS Windows: closed, near monopoly: bad
MS Office: closed, near monopoly: bad
Skype: closed, going for monopoly fast: good.

Riiight...

Re:Isn't that the point?

[Rogerborg]

Yes, I could.

Re:Isn't that the point?

[Lemmy Caution]

A university is neither advertised as or designed to be a no-holds-barred ISP. You go to a university for an education on their terms, not for unlimited internet usage.

Re:Isn't that the point?

[drsquare]

When the students signed up, I doubt there was any guarantee of Skype connectivity.

Success of Skype

[dyefade]

It's getting to the stage now where I know people who say "Skype" when they mean "VoIP/SIP". Admittedly, it's early days in terms of adoption of the technologies, but this is a little worrying. Seems like very few people in the real world have any concept of open standards etc.

Re:Success of Skype

[NineNine]

Seems like very few people in the real world have any concept of open standards etc.

Are you kidding me? Are you just now realizing this? What would make you think that people in the real world even know what open standards are, in the first place?

Re:Success of Skype

[chrisbeatty]

Consumers have always been like that, if a brand name is pushed early in a new technologies lifespan. Think of all the people who go to their local electrical store & ask for a "Hoover" rather than a vacuum cleaner.

Wandering round some superstores recently here in the UK I spotted Skype branded USB phones for broadband users, so here begins the mainstream usage of Skype instead of VoIP.

Re:Success of Skype

[squiggleslash]

It works the other way around too. I see people who hear the term "VoIP" and think this means "Skype" or, at a stretch, "Vonage". Oddest case is the confusion over a service called UMA, a technology that lets you use an 802.11 WAP with an Internet connection as a GSM tower. Because it's "VoIP", otherwise bright people will start asking why anyone would use this in favour of Vonage, or say they're looking forward to it because it means they can use Skype from their mobile phone handset.

Brandname and technology confusion is one big mess.

Re:Success of Skype

[mackyrae]

I only heard about Skype really recently. There was a technology fair at my school where they had Skype people there. They said it doesn't work on Linux and I told them Ekiga Softphone was just fine with me then. I've had Vonage in my house for a bit over a year though. It only took about a month for someone to tell me it's VoIP. That's how I always describe it someone first. Hopefully by saying it's "VoIP" or the full wording "Voice over IP" and then "it's for phone calls through the internet or voice or video chatting" they get the distinction.

the very idea

[thrillseeker]

of my PC having its resources tied up for someone else's phone call is frankly maddening to me

... but I have no problem with tying up someone else's resources when it's for my convenience ... ?

Re:the very idea

[Have Blue]

He'd prefer that the supernode feature be removed entirely and Skype calls only ever consume the resources of the consenting parties directly involved in it.

Re:the very idea

[gEvil (beta)]

Didn't you get the memo? It's okay as long as they don't know you're using their resources...

Re:the very idea

[Shadowmist]

Wired ran an article on Skype. The reason that Skype can run as it does with the majority of users not going beyond the free service is that the supermode makes it possible to run a bittorrent style phone system (my choice of words). Remove it and Skype effectively ceases to exist as a commercial venture. The free solutions simply can't provide the services that Skype or anotehr commercial provider does.

As an aside, I believe Nikotel uses SIP. The software I have from them as settings for SIP servers.

Re:the very idea

[jacksonj04]

I was wondering if the author ever uses BitTorrent. Because there's obviously a huge difference between someone using your resources to exchange data over the internet, and someone using your resources to... uh... exchange... umm...

Re:the very idea

[stuuf]

Actually, the difference is that BT lets you throttle or even disconnect torrents on an individual basis, while Skype is all-or-nothing. With Skype, you have no control over when you'll be forwarding some random person's phone call, but you can only send data to BitTorrent peers if that specific torrent is running, and you can always control how much bandwidth you allow them to use.

Re:the very idea

[tfinniga]

He'd prefer that the supernode feature be removed entirely and Skype calls only ever consume the resources of the consenting parties directly involved in it.

.. which implies that Skype would no longer work through the majority of Firewalls. Skype's success is in part because the business folks can download it, install it, and get it working without having to ask the network guy at the company to please poke a hole in the firewall for port x to my laptop. Or the network guy actually doing it. Or the business guy even being able to formulate the question, instead of saying 'geez, that didn't work. Oh well'.

So that means...

[Anonymous Coward]

the very idea of my PC having its resources tied up for someone else's phone call is frankly maddening to me."

So that means you don't use bittorrent either?

Supernodes "maddening?"

[cbreaker]

"the very idea of my PC having its resources tied up for someone else's phone call is frankly maddening to me."

Well, boo hoo. It's the way the system works. I seriously doubt any significant system resources would be used up for other people's calls. When you make your calls, it happens to other people. It's a give-pull situation where everyone has to share resources in order for the system to scale with the number of subscribers. Would you rather have nothing?

Re:Supernodes "maddening?"

[EVil Lawyer]

"It's the way the system works."

But it doesn't have to work that way. Gizmo Chat functions perfectly well (I think the voice quality if actually much better than Skype), without requiring users to traffic others' data.

Re:Supernodes "maddening?"

[tyldis]

It ate enough to drain my 2mbit home SHDSL. It's banned on sight, I block it at work (250 employees and 400 pupils), and I remove it from any family machine that is 'slow'. I concluded that Skype sucks. Use one of the IM networks instead, many of them supports voice chat too.

FUCK YOU FREELOADER

[Anonymous Coward]

If you don't want to run as a supernode, don't make voip. Scumbags like you don't deserve to use any community service. Good luck downloading from a filesharing service, you'd be banned by everyone you tried.

LEECHER

Re:FUCK YOU FREELOADER

[hahiss]

Yeah, totally! That'd be like participating in an online forum as an anonymous coward!

Re:FUCK YOU FREELOADER

[Anonymous Coward]

Yea....a name like 'hahiss' commands MUCH more respect than anonymous coward....

Re:FUCK YOU FREELOADER

[thrillseeker]

Yea....a name like 'hahiss' commands MUCH more respect than anonymous coward....

Infinitely more.

Doesn't play well with others

[Rob T Firefly]

"One tidbit of information that most people are not likely aware of is that when you install the Skype client, it will drain system resources by running as a supernode from time to time. Granted, this is not always the case; however, the very idea of my PC having its resources tied up for someone else's phone call is frankly maddening to me."

Erm.. that's kind of the point of decentralized P2P, you leech.

Re:Doesn't play well with others

[svanstrom]

Yeah, but Skype isn't advertized as decentralized P2P, so most people won't know that that's how it works when they install it; and most people using Skype doesn't even understand what decentralized P2P is.

IM-programs have for years _NOT_ been decentralized P2P-based, and Skype is largely competing with other IM-solutions; so it's not like people expect it to be P2P in the sense that their computers are used for other peoples filetransfers etc.

Re:Doesn't play well with others

[svanstrom]

That didn't come out exactly as I meant to write it, so please, read what I meant to write, not what I actually wrote.

But, hey, that just proves that average people don't get a chance to actually learn how e-stuff's working, as people like me write confusing stuff in forums like /. =)

Re:Doesn't play well with others

[Rob T Firefly]

You made your point well enough that I could understand it, which might be cause for worry actually. Get thee to a therapist!

But seriously, as much as I appreciate the fact that Average Joe Sixpack can't really be bothered learning anything about what the magic bleeps, sweeps, and creeps inside his computer box are really doing, I can't have much sympathy for him when he starts complaining about stuff he chose to use working as designed. Computers are nearly as ubiquitous as cars nowadays, and people who own a car are expected to know enough of the basics to not fill their petroleum tanks from the diesel pump. You don't need to be a licensed mechanic or chemical engineer to point and laugh at the person who does, and then wonders why their car stops going.

What a bunch of crap...

[rthille]

Sure, I prefer open solutions, but to say that Skype will drain your system's resources is just crap. A simple consumer firewall between your skype-running PC and the internet will prevent Skype from using your PC as a 'supernode'.

Re:What a bunch of crap...

[Plutonite]

That is a hack, not a clean solution. SIP is standard and you can write your own clients and SIP servers/PBX boxes, so why go to these unhealthy measures?

Re:What a bunch of crap...

[Jaseoldboss]

That has been my experience too, I'm behind a NAT router and I've never had any problems with bandwidth / resource hogging.

I wish Skype was open source too but I use it because it runs on my PocketPC easily whereas not many other VoIP clients do.

Re:What a bunch of crap...

[Anonymous Coward]

that's just not true poncho - skype can traverse nat and re-route packets, defeating most consumer firewalls. adios now.

Re:What a bunch of crap...

[spinkham]

Yes, skype can traverse NAT, but cannot be a supernode for others when it is behind NAT. That is what your parent post was saying.

Re:What a bunch of crap...

[Anonymous Coward]

Which doesn't work at places like Universities where you need a real IP connection and not a faked IP number to do your work.

Re:What a bunch of crap...

[Technician]

A simple consumer firewall between your skype-running PC and the internet will prevent Skype from using your PC as a 'supernode'.

And the traffic gets re-routed to some other sucker. We had a problem with a surge in traffic on the corporate LAN. It initialy got flagged as a worm or virus attack due to the large number of packets. The packets were traced to individual PC's (tracking the jabbering bandwidth hogs as possible botnet nodes) and found the drain on the system was the new version of Skype which was just released. A company wide memo went out detailing the issue with instructions to not run the new version of Skype until the bandwidth issues were resolved.

The system will not work without supernodes and supernodes are system bandwidth hogs.

As more business protect their bandwidth, the number of supernode possibilities dwindle placing an even higher demand on the few remaining. Supernodes will bo away or become hard to find just like open mail relays. The few remaining ones will be buried in bandwidth consumption.

So, now the shoe is on the other foot?

[Hektor_Troy]

So - it's cool if others donate their time (and other resources) to give you something for free (SIP - both the protocol, but also a LOT of the programs for it), but if YOU have to give something of your resources (like bandwidth) for free - well, that's something COMPLETELY different.

Somehow I don't see how that works.

Sure, Skype is proprietary - but I've never paid anything for it (except bandwith), and it works just fine for me, so - to me at least - it's free (monetary, not libre). SIP - well, never tried anything that worked just as well as Skype, so it's libre, but it's not free to me (costs me and others resources like their and my time to get it working).

I don't really see the difference (but I'm not a fanatic proponent of Libre software).

Re:So, now the shoe is on the other foot?

[Lussarn]

Skype is a black hole. Sure I could open it up in my firewall but why would I? As I understand it skype could easily use a couple of gigs of bandwidth every month with no way to control it or even measure the usage. I could probably set up a couple of QOS rule to tame it down but that would take time, and the only benifit I would get is letting an unknown protocol connect to my home computer through a closed source app.

I'm also sick and tired of installing all these proprietary apps, each with it's own protocol and from the looks of it every couple of years there is the next big thing you need to install. Not because it's actully better but because someone you need to write/talk to has it. No thanks, we need something open and documented. Then every company could make their own client, brand it, sell it and popup commercials all day long as they wish. And I could use something smaller OSS that suits my needs.

And I would gladly contribute both bandwidth and cpu usage. But never for skype as it stands now.

Re:So, now the shoe is on the other foot?

[Infernal Device]

because someone you need to write/talk to has it.

Well, when everyone magically switches over to free and open, you can join in. Until then, I guess we'll have to do without ya.

Re:So, now the shoe is on the other foot?

[arose]

Sure I could open it up in my firewall but why would I?

The problem isn't opening your firewall for Skype, the problem is closing it.

Re:So, now the shoe is on the other foot?

[Lussarn]

I don't know where you got the free from as I didn't mention it. Maybe you like making things up to make your nonsense argumentation hold water.

Re:So, now the shoe is on the other foot?

[harmic]

Yes, this is the main point!

The problem is that unless & until every single person is using the same proprietary system, you need to have an account on each and every one in order to be able to reach them. To say nothing of all the clients you need to download and install.

Contrast this to (for example) the normal phone system where you can get a service with one provide and be sure to call another subscriber from any other. It all works because they all adhere to open standards.

Do we really want Skype to be one and only Telco left standing when it's all gone IP? That's the way it is heading, and they owe it all to being the first to get off the ground with a reliable easy to use Voip solution, combined with the lock-in they have been able to achieve.

Having said that, almost every one of my friends and co-workers use Skype almost exclusivley. So maybe it's too late and the battle is already won. Most of them are not even interested in the alternatives. And I work in the Telecoms Industry!

IAX?

[zotz]

"If you were to make the choice between SIP and Skype for Linux, which one would you go for?"

IAX I guess...

if all of that stuff was legal down here. That is not so clear.

all the best,

drew
http://www.ourmedia.org/user/17145

Re:IAX?

[ncw]

Yes!

Sip plays merry hell with firewalls. Don't even think about it unless you've got a VPN back to your sip server! If you have then it works great. The new Nokia E70 phone connects to our office Asterisk server via SIP and works very well ( http://europe.nokia.com/phones/e70 ).

IAX2 goes through NATed firewalled links just fine. It is much easier to configure if you are on the move (or your users are).

I wouldn't touch Skype with the proverbial barge pole given its closed nature.

Re:IAX?

[RGRistroph]

I agree that IAX2 is the way to go, because of SIP's firewall and NAT problems.

I have even had trouble with SIP over some VPNs.

However, there are not as many IAX2 softphones available, as there are for SIP.

Re:IAX?

[element-o.p.]

How many do you need?

There may not be as many IAX softphones as SIP softphones, but they are available, whether your choice is Linux, Mac or Windows. If you are looking for a good IAX softphone, I'd recommend either idefisk http://www.asteriskguru.com/idefisk/, kiax http://sourceforge.net/project/showfiles.php?group _id=131960 or iaxcomm iaxclient.sourceforge.net/iaxcomm/. I have used all three, and all of them work well, but idefisk is probably the most feature-rich, the best documented and has, IMHO, the best looking UI. Kiax isn't bad, but isn't as pretty. While iaxcomm works well too, but it's not as well documented as the other two.

Re:IAX?

[HuskyDog]

A few months ago I tried to attach my Mother-in-law (who lives overseas) to my Asterisk server. I bought a SIP analogue telephone adapter and went to visit. I spent at least 2 hours a day for 8 days trying to get it to work. I fiddled with every setting on the ATA and (via an SSH tunnel) loads of settings on my router and I never got the ATA or any SIP softphones to work. Finally, I tried an IAX2 softphone and it worked first time.

So, when I returned to the UK I bought an IAX2 phone for the same price as the ATA and sent it to Estonia. My Mother-in-law plugged it in and it worked first time. Now she and my wife chat for hours without it costing me a penny.

Conclusion: SIP works fine on a LAN (where I now use the above ATA), but if you have any NAT anywhere in the link then the pain of making SIP work isn't worth it when you can get IAX2 kit for the same price and it "Just Works".

Re:IAX?

[docfaraday]

I like to think of it as nats/firewalls play merry hell with SIP. ;) However, this is a problem that the IETF recognizes, and is solving, both in the SIP sense (draft-outbound), and the general sense(STUN, TURN, and ICE). We will (hopefully) be getting our first big interop test of these protocol extensions in a couple of weeks.

Okay,

[Anonymous Coward]

but it's fine if you tie up someone else's resources for your own phone call?

Suppressed Information + Fear

[DingerX]

Article translation:
SKYPE: OMG! A supernode! you gotta be kidding me! You mean if I turn it on, it might use more bandwidth than I imagined? And if you use it to make phone calls, and lose your password, you probably won't get your money back.
Gizmo: Well, at least it uses SIP.
Full Open Source SIP stuff: Now this is the way to go. Too bad there's not much out there anybody else uses.

Okay, it's Mad Penguin, but who exactly are we preaching to?

Supernodes. Yeah, skype does that, and it can be a pita. If skype is running more than 4 contacts, you've been elected. If you don't like it, shut it down. If you can't monitor your network activity, and are running Linux, what kinda geek are you?

Terrible news if you lose your skype password, you might lose up to 25 bucks! If you were using an open-source alternative, you wouldn't have this problem, because you wouldn't be making or receiving PSTN calls.

The #1 reason why I use Skype over SIP: It's encrypted. At least that's what they tell me. Give me a solution that's F/OSS and uses point-to-point encryption, and I will switch to the superior product. #1 reason why others use Skype: it just works: those supernodes do their job and it blows through most obstacles those idiots in IT try to put in the way. Turn it on, it connects and it works.

Another interesting Skype weakness: A second client can be connected to skype under the same account, and will receive a copy of all correspondence without the other client knowing about it.

Re:Suppressed Information + Fear

[Isao]

The #1 reason why I use Skype over SIP: It's encrypted. At least that's what they tell me.

And what they tell you is true. No one has access to the keys except you and the party you're Skyping. Oh, and Skype.

Hmmmmm.

Re:Suppressed Information + Fear

[beyondkaoru]

here's some encryption for ya

http://www.philzimmermann.com/zfoneproject/index.h tml

also, skype's encryption and how they do it is not viewable to me. thus, there are blatant issues with me talking over skype and hoping that their encryption is 1) strong enough, 2) they won't divulge my key, 3) they will establish the keys well, 4) there aren't hidden back doors. i personally can't really tell what's going on with skype. i use it when i talk to the unenlightened, but i don't talk about anything that requires encryption to them, and really don't use voip much anyway. i tell them that if they want to be able to talk to me about such things via voip, that it'll be through something that shows me some source.

as a bit of a crypto buff, encryption means a lot to me--but the fact that you're trusting skype means that it probably doesn't mean much to you.

( um, sorry if that came off a bit harsh... )

Re:Suppressed Information + Fear

[Anonymous Coward]

RTFRFC. (3261, sec. 26.2.1 onward).
SIP signaling is designed (and in some cases, recommended) to work over TLS.

And at least with SIP over TLS, *you* control who has the certificates, their key-length, and which CAs you decide to trust.

Of course, SIP purely concerns itself with signaling - the RFC doesn't describe anything about encrypting media. Though there's nothing to stop a SIP implementation using encrypted media too (if you could find a system where the CPU could handle it in a timely manner, that is...).

Re:Suppressed Information + Fear

[Anonymous Coward]

If you are using the Gizmo soft client (http://www.gizmoproject.com) and calling someone who is also using the Gizmo soft client your call will be encrypted (SRTP i believe).

Re:Suppressed Information + Fear

[DingerX]

Actually, that was my point. Now that Ebay owns skype, and the FCC apparently mandates VoIP backdoors, who knows what's going on with Skype encryption? In any case, with skype, the weak point doesn't even have to be the encryption; the user password delivers "the keys to the kingdom" with no oversight. Skype delivers the private key based on a relatively unsecure password, and there's no way to tell how many clients are connected under the same username, or even if someone tried a brute-force attack on a password. So even if they establish the keys well (which, seeing the obvious security holes, is questionable), and even if they haven't divulged to DHS's unquestionably impenetrable servers, and even if there are no backdoors, it's still not hard to get.

Thanks for the info about zfone, that is useful and good news, and to me, far more interesting than TFA.

Re:Suppressed Information + Fear

[Anonymous Coward]

ooo "i tell them that if they want to be able to talk to me about such things via voip, that it'll be through something that shows me some source."

what a crock going for mod points.

So you do not drive a car without a full schematic to said car? give me a break. Is every single part of modern cars available for inspection? (well if one takes the car apart down to the last screw and bolt maybe) but other wise no. Your dealer is "authorized" to have the plans. On a new model car they are even behind (Read: without the plans) for a while. Does that mean you would not drive that car?

And who is to say that Skipe didn't actually create some new language (a hell of a lot of masters CS majors have written their own compiler and/or programming language). They could have used a language that is totally new and by not saying "Hey Skype is written in skyp-type version 1.3" they slow people from going out and hacking it.

Not everything is 'open source' for a reason. If all applications were totally open source, software companies (and jobs) would be a dime a dozen and just about worthless. No company could keep how it does something from everyone else. Company A creates a great new spead sheet program with great features in open source. Company B looks at the source create the same thing and sells it for $10 less then company A. Company A drops the price to match. Yes consumers win with better prices. But Company A is losing money since it had to develope the spreadsheet program while Company B just looked at the source and copied it.

no incentive to create new products. build a better mouse trap and give it away? Great if you already have enough to live/support you family on/ and retire. but it will not work for the rest of working class folk.

Re:Suppressed Information + Fear

[Anonymous Coward]

And who is to say that Skipe didn't actually create some new language (a hell of a lot of masters CS majors have written their own compiler and/or programming language). They could have used a language that is totally new and by not saying "Hey Skype is written in skyp-type version 1.3" they slow people from going out and hacking it.
This point is completely off the wall, and has nothing to do with anything.

1.) Language it is in doesn't add or subtract securicty, as it's all machine code after it's compiled.
You can write the same program in different langauges and get it to compile to logically equivelent machine code
(+- some overhead)
A.) If the encryption method is good is independent of the language.
B.) If it has a underlying protocol or software bug is independent of the language

2.) It can be decompiled and read through, but decompalation is messy and would violate the EULA.
A.) It can't be more secure simply from being written in a different language, it's still machine code when it runs...
B.) It's flaws cand and are still found by those who want to do ill by looking at the network traffic.

3.) They are crying for an open protcol, not neededly an open client (though that would be even better). The two are different, read on.

Not everything is 'open source' for a reason. If all applications were totally open source, software companies (and jobs) would be a dime a dozen and just about worthless.

Because no one can make money in opensource? See: Suse, Novel, Red Hat, et. al.

No company could keep how it does something from everyone else.

Why should it? Not that they don't have a right to, but you are proposing that opening everything up would put everyone out of bussiness...
1.) Open doesn't mean they don't charge for it.

2.) Just because I know how to make a hamburger doesn't mean I don't go to Burger King or Mc.D's every now and then.

3.) That's not what they are asking for, they don't want the code to Skype, so much as it's protocol....
(Though there are those who demand both before using any software...)

Company A creates a great new spead sheet program with great features in open source. Company B looks at the source create the same thing and sells it for $10 less then company A.

Both are still more expensive than OpenOffice. Get OpenOffice, it's free and open... :) And we're not saying everything must be made open source by law. In this case, all they are asking for is some assurances that their calls aren't being listened to, that they are encrypted properly and that they can better see what traffic Skype is putting on their switches, routers and *scowls* hubs.

Company A drops the price to match. Yes consumers win with better prices. But Company A is losing money

1.) Losing money? They chose to open source it...

2.) Just because they release the source doesn't mean their EULA and licenses allow for copying...

no incentive to create new products.

You haven't searched source forge in while have you? Pick a random type of application that you've wanted and search for it. You'll find a trove of applications that suit your needs, each with a different code base, each open and free, each with different innovations. Look at Linux and the gigantic collection of different apps that have been Open Sourced, and then tell me they have "no new products."

build a better mouse trap and give it away? Great if you already have enough to live/support you family on/ and retire. but it will not work for the rest of working class folk.

A lot of FOSS movment was average joe's supporting families and working a regular 9 to 5, and writting code fo

gtalk

[hey]

Its worth considering Google Talk (Jingle protocol).
It uses XMPP (Jabber) then kicks up to Jingle for voice.
Nice.

Re:gtalk

[hanssprudel]

Are there any linux implementation of XMPP + Jingle? Google seem to say otherwise...

What Skype provides very nicely is something that a) I can use in Linux b) My friends can easily install and use in Windows. The a) part is true of various SIP implementations, but I have never seen one that was one-click-and-run in Windows, while the b) part seems untrue regarding all the other IM-with-voice applications (including gtalk).

Re:gtalk

[msh104]

jabbin 2.0beta ( http://www.jabbin.com/ ) allows you to talk to jabbin users.
I also heared that kopete has experimental jingle support, but that not very usable yet..

Re:gtalk

[msh104]

"allows you to talk to jabbin users." has to be "allows you to talk to google talk users."...

Re:gtalk

[arose]

Are there any linux implementation of XMPP + Jingle?

There was some talk about Gaim 2.0 having such functionality, no idea what became of that.

[..] I have never seen one that was one-click-and-run in Windows [..]

Gizmo might be what you are looking for.

Re:gtalk

[kripkenstein]

Are there any linux implementation of XMPP + Jingle? Google seem to say otherwise...

You can use Tapioca on Linux. Get your Windows friends to use Google Talk instead of Skype, and you are good to go with VoIP.

Re:gtalk

[JayAEU]

I'm glad somebody finally mentioned Gizmoproject! It works really well (even on my Nokia770!) and allows for free calls to landlines if your contacts put them into their profiles.

Best of all, you can connect direcly to an Asterisk PBX using IAX with it, if you want to.

Re:gtalk

[dovf]

There is a branch of psi which supports jingle at http://psi-im.org/wiki/Jingle_branch. I've tested it with gtalk once or twice and it works, but I don't really know anyone who uses gtalk...

Opensource

[kernel_pat]

"With Skype, I bog down my PC, and still have to look myself in the mirror as many of my friends shake their heads with disgust." - surely running as a super node for 5 minutes a month isn't that bad.

Re:Opensource

[Simon80]

I don't understand why this is even a serious debate here, the answer is a no brainer. Skype is a closed protocol, closed source app, you can only call other Skype users, and only using a softphone. SIP is an open standard that lets you use a variety of different services to provide an address for the calls, depending on the service you can usually call people with a SIP address at any other service, not just people at your own, and you can use whatever client you want to make the call. This can be a softphone, a physical IP phone that resembles regular PSTN phones, or you can use a regular phone to dial into an adapter that will connect the call over SIP, and some of these can fallback to the PSTN when applicable as well. So, in my humble opinion, Skype is a joke, and this is like comparing go-karts to automobiles. There's no contest here.

Landline

[Gamefreak99]

Until the competition let me call a landline through their product for free, as Skype does at the moment, I won't be switching.

Re:Landline

[Malc]

How long do you think that's going to last? And BTW, that's only N. America.

I just switched my home line to Vonage. I can now call the UK from Canada for no additional cost. Skype doesn't let me do that. Not everybody I know that I need to call has a computer, or wants to be tied to it for calls. I could probably make Skype work out cheaper, but it doesn't have all of the features of Vonage, so right it can't be my primary method of telephony.

Re:Landline

[Anonymous Coward]

Well, you get that for the US and all of Europe, using Wengo:
www.wengo.org. And it uses SIP. And the client program is Free
Software (GPL). And it is multi-platform.

Anything else you need ? :-)

Stephane

Re:Landline

[Firehed]

Fair point. But what about if/when someone creates a thin-client Skype box (in effect, a Skype-equivalent of a Vonage "modem")? I spent $6 on a microphone and have replaced a good number of otherwise-expensive cell calls with free Skype calls (by the way, the free SkypeOut lasts until the end of the year). While I certainly can't speak for you, all of the functionality I really require from my phone carrier is being able to call people, and Skype gives me that.

Re:Landline

[Malc]

In fact I can get this for my home phone system. It still requires a computer running and the management of that.

I've also seen some 802.11 Skype handsets, which is cool. Although I don't want anymore phone systems (work line in home office, home phone system and mobile phone are already too much).

I will consider what you suggest when Skype is as reliable, feature complete (including 911 service) and easy to use (plug in and go with existing phones, no hassles with credits like they have, and not require a computer) as Vonage.

Right now it's a good tool, but no replacement for what I have. If I was on a tight budget, then I might consider it for exclusive usage, but I'm not/

Re:Landline

[Knuckles]

Anything else you need ? :-)

Encryption :)
Oh, and it's wengo.com, wengo.org is the private site of some dude.

Re:Landline

[rhnk17]

Well, I know it sucks to be french, but my beloved ISP provides me with SIP, free international phone calls, including to mobiles in the US. Not that I use it so much (since I cannot get the line-in to work on my laptop), but it is nice in principle :)

Re:Landline

[teknopagan]

You mean like Gizmo? Skype lets you call US and Canadian landlines for free, at least through the end of this year. Gizmo lets you call landlines and mobiles in 60 countries for free, forever, as long as you both are Gizmo users and use the software a few times a week.

Re:Landline

[generic-man]

12/31/06. It's a marketing promo and was clearly stated as such.

Re:Landline

[Tony Hoyle]

Until the competition let me call a landline through their product for free, as Skype does at the moment, I won't be switching.

I take it you've never actually used SIP then?

Skype is *far* more expensive than 99% of SIP providers (and due to the nature of SIP you can have more than one configured at a time - I have about 5 at the moment). I can call nearly anywhere in the US and europe for just the connection charge.

Control freak...

[Vellmont]

the very idea of my PC having its resources tied up for someone else's phone call is frankly maddening to me

This strikes me as an attitude of someone who can't stand the idea that he's not in control of everything (which you never are). The real question is, does it use any significant resources that effect what you're trying to do at the time? Frankly I don't really care about 20-50 megabytes of memory, or 5% of my processor usage, or even 100% of my idle processor usage. Those numbers are all low enough that you'd more than likely never notice or miss those resources. I would be concerned if the app started taking up hundreds of megabytes of memory, or 30-40% of my processor time, or locked up system resources that interfere with other apps I'm running. So which is it? The author didn't provide us with any of that information, only the extremist position that ANY useage of his computers resources that wasn't for him was unacceptable. What a useless article.

Re:Control freak...

[Ptur]

What about 100% of your uplink bandwidth? Happened to me, won't happen again!

Re:Control freak...

[silas_moeckel]

Funny I have a fairly smart firewall meaning PC's at my home and be used as supernodes leave skype turned on for any ammount of time and I can watch my uplink bandwith max out to what QOS allows for unknown traffic. I run SIP with ENUM and strangley anybody else with SIP and ENUM can call be for free without any other service provider involved in the call past ENUM. Sure you can tap the phone call but you can tap land lines and Skype for that matter.

Re:Control freak...

[Trogre]

Frankly I don't really care about 20-50 megabytes of memory, or 5% of my processor usage, or even 100% of my idle processor usage. ... until you receive your next power bill.

Re:Control freak...

[Technician]

Frankly I don't really care about 20-50 megabytes of memory, or 5% of my processor usage, or even 100% of my idle processor usage. Those numbers are all low enough that you'd more than likely never notice or miss those resources.

I do care however when my home network gateway traffic is consumed and I want to load a web page or something. The remaining bandwidth is a kick back into dial up speeds for the family.

Having a spare PC to donate idle CPU time with is not the problem. The problem is I don't have an extra broadband connection I would like to donate to the cause. I use my bandwidth. My internet gateway is my bandwidth choke point. I would like more bandwidth, not less.

jabbin

[msh104]

I recently discoffered jabbin.
http://www.jabbin.com/int/ it's free as in speech, and has voip support.
perhaps he should give it a try. there are windows, linux and mac releases.

Re:jabbin

[lixee]

I've been using Wengo for a while now; Give it a try! http://www.wengo.com/

What about the advantages of being a supernode?

[demallien2]

Of course, this wonderfully balanced, well-researched and well-written article did overlook one rather important point: The whole supernode concept lets Skype get through nearly ANY router configuration imagineable. I beat my head against a brick wall for three months trying to convince my father's ADSL modem to let through voice comms for a SIP client. No go. The only way to get a VoIP solution through was to install Skype.

Correct, but bad reason.

[Mathiasdm]

The guys's right about SIP being better, but his reason is wrong.

SIP is better, because it allows more interoperability (open standard, duh!).

Run away, run away .........

[slightlyspacey]

I love Skype, I really do. The program is slick and works well. But they have SERIOUS problems handing purchases for Skype-Out (their PC-to-landline service). The complaints are numerous ... so numerous in fact that Skype has had to set up a separate forum to handle them all. Here's a rundown of my personal nightmare with them. You really, and I mean REALLY, need to look at the problems that Skype is having before you go with them.

Re:Run away, run away .........

[Malc]

Sound quality Skype-to-Skype is better than anything else I've used, except when the call is breaking up. I have more problems with that than Vonage... if something else is using my CPU, or the other person's, or some random internet thing and we can't talk very well and the better audio quality is moot.

I've had problems with credit cards too. I run two Skype accounts (personal & work) because they won't support anything in the client that will allow me to operate that way. Buying SkypeOut credits for two accounts requires two credit cards *sigh*.

BTW, you can trick Skype in to running multiple instances under Windows (and thus login with multiple accounts concurrently) by using Run-as and having one of the processes running as another user on the system.

Re:Run away, run away .........

[Anonymous Coward]

Oh, I'm with you on this one. There are all sorts of crazy limits on SkypeOut purchases.... $30 on Paypal for the first month, $20 on one credit card, etc. It just makes the whole process feel very unprofessional. And yeah, Skype is a free product, but it is run by EBay and should be expected to be run in a professional manner.

Cringely on Skype

[richg74]

Back in July, Bob Cringely at PBS had a column in which he talked about Skype and its use of super-nodes.

Gotta love this...

[QCompson]

OK great, so how does this help me when calling my friends on Windows? Why, the beta release of Ekiga for Windows, of course!

What's that? Oh you want to talk with me via VOIP? Nah, don't use that program you use with all your other friends and family, install this nifty beta program just so you can talk with me!

Re:Gotta love this...

[Sarkoon]

The whole point of a standards protocol like SIP is that regardless of what client you or your friends are using, you can all still talk to eachother! Imagine if you had to use the same email client that everyone else uses - we would all be using Outlook Express! With Skype, you're locked into the proprietary Skype client using their proprietary protocol and don't have the freedom of chosing the *best* client for your requirements.

Re:Gotta love this...

[Ash-Fox]

With Skype, you're locked into the proprietary Skype client using their proprietary protocol and don't have the freedom of chosing the *best* client for your requirements.

Well, perhaps you can help me. My requirements are zero configuration beyond which sound card to use and login credentials.

This means I don't want to mess with port forwards, tunnelling on restricted networks where the only outgoing port permitted is 80 through a transparent proxy [doesn't allow proxy connections over HTTP], not even HTTPS being available [unless you use that HTTPS proxy on the network -- which doesn't allow proxy connections over HTTPS] or even figuring out how to get my connections encrypted. Something this easy which family, friends and I could run on Linux and Windows (a MacOSX version is not needed).

I look forward to your reply.

I'm surprised to hear people still talk...

[xxxJonBoyxxx]

Frankly, I'm surprised to hear that people, especially Slashdotters, still talk to each other. I'm guessing this "voice" thing is some kind of emergency backup in case your email and instant messaging clients go down.

Why I initially chose Skype...

[emag]

One word: laziness

Longer reason:

I really didn't want to have to learn the intricacies of a protocol in order to get everything up and running. I'd been seeing various things that at least *implied* that I'd have to start mucking about with firewall rules in order to get SIP running. This was something I had zero interest in doing at the time. I also wanted something that would be cross-platform in an easy manner (I was looking at this so my manager & I could keep in touch while we both worked from home, without using cell minutes or LD charges....him Windows, me Linux).

Then I needed to be able to call out to POTS lines. Enter SkypeOut. No monthly charges, just a relatively low per-minute charge (which was OK, I still, after 16 months, haven't used the initial 10 Euros I put in). Then I needed people from work to be able to contact me, and I didn't want to give them my cell or house lines. Enter SkypeIn. $38 for a full year, with voicemail. Usable anywhere. That was a big draw. So long as I had a network connection, I could head off to a family member's place for a long weekend out-of-state, and still be reachable. No problemo spending 8 hours with sun and surf in the background and me being several hundred miles away...

And then things soured... I tried to renew my SkypeIn number. Failed. Again and again and again. Skype's purchase process is rather....opaque. They use a variety of 3rd party payment processors, and all Skype can tell you is "success" or "failure" until you start bitching about being unable to pay. Though don't expect an immediate response, as it will take up to 4 days. And then, if you're like me, you'll be told that your NATed laptop running Linux on a static IP with no proxies is "an anonymous proxy", and be told to check you IE settings to ensure you're not using a proxy (yes, IE settings in Linux...). You'll be told to, get this, try a different ISP. And even though you'll have already tried multiple credit cards, and multiple browsers with them, you'll be told to try another credit card, or another browser. Or worse (IMNSHO), another payment method that until just recently announced, had practically NO consumer protections (way to pay, pal!).

Ultimately, I ended up with access to work's terminal server, and after one too many complaints from the muckety-mucks who'd already been given my cell number (remember I didn't want to do that?) because I couldn't renew my SkypeIn, I decided that I could make a business case for using company resources for attempting to renew. And....it worked. NFC why, but it did.

So, now I have about another year to come up with another solution that'll work for me on random networks, doesn't require special hardware (other than a headset or speakers+microphone), and doesn't have recurring monthly fees, as I don't actually make calls every day, or even once a week. SIP still gives me a headache just trying to wrap my head around. Trying to figure out WHICH providers offer WHAT parts of what Skype offers as an all-in-one package is something I tend to just grow bored trying to research. Some of the more promising-looking clients seem to be geared towards specific providers, while others leave you trying to guess who to go with. Ick. I really don't want to stick with Skype having experienced the bad side of things, but I'm afraid momentum an just how unfocused SIP solutions are for what I want will force me to stay.

(Let's not even get into the whole Skype's Linux client lagging way behind their Windows client, with the Mac client having leapfrogged Linux at some point. There HAVE been a few betas that have finally brought support for ALSA, and some UI improvements. Still miles behind Windows & Mac, which is frustrating, but there's been at least some progress now almost a year after their last major Linux release)

Re:Why I initially chose Skype...

[Malc]

No problem for me with SIP. I think my SpeedTouch 546 ADSL modem was already configured for IPQoS for voice communications. I plugged in my Vonage router behind it and had no call problems, even when swamping my line downloading stuff. Skype OTOH hand seems to trip up as soon as anything hits the CPU or bandwidth.

Re:Why I initially chose Skype...

[mnmn]

Wow thats a long reason.

Given my laziness, can you give us an intermediate-sized reason?

Re:Why I initially chose Skype...

[emag]

Ok, so if I have specific network hardware on a specific network, with specific additional hardware from a specific provider that charges monthly fees, SIP will be rock solid? Care to address my original points of:

* random networks
* no special hardware
* no monthly fees

I could add to that the implied points of:

* Not having control of the network or hardware
* Not having control of the firewalls

though those could reasonably be assumed to be part of the "random networks" requirement.

Re:Why I initially chose Skype...

[quintesse]

Boy you must find it difficult to make decisions in life ;-)

Or they make it easy for you and offer a client to go with their service or you got options which means you can make your own choice. And even then you don't know what to do?

It seems you just accepted Skype without looking at the alternatives because as far as I can see most SIP providers offer complete packages with call in and call out etc. I'm actually "subscribed" to 3 of them with "subscribed" meaning that I've got call out credits or something similar. The reason I have more than one is because of the difference in rates, I need to be able to call to several countries in different parts of the world and there is not one provider offering the lowest price for all of them. And I can tell you Skype definitely isn't one of the cheapest.

In the end SIP is all about freedom of choice, _I_ decide which provider to use which makes it possible to find one (or in my case several) that suits my needs. I also decide which client to use. Because even though Skype might work pretty well it is far to "heavy" for my taste, I like my programs simple, cleanly designed and "light". Having an open protocol also means you might find it integrated into several of your favorite apps, in my case MythTV (a TiVo-like application for Linux).

All of that makes it a no-brainer for me: SIP.

Re:Why I initially chose Skype...

[liloldme]

which was OK, I still, after 16 months, haven't used the initial 10 Euros I put in

Did you know that your 10 euros will expire (probably fairly soon). I put 20 euros in, only have used 2 euros so far (some life changes that didn't require me to make that many international calls anymore plus Skype quality for intercontinental calls is so abysmal I ended up using a more "traditional" voice over IP phone service [cheaper than Skype too!!] instead).

My left-over 18 euros is about to expire in 4 months. Better check your account to see when your 10 euros will be gone for good. Or start making phone calls soon!

Re:Why I initially chose Skype...

[emag]

I make one at least every 180 days, which is enough to keep it from expiring.

Re:Why I initially chose Skype...

[emag]

More like the initial was "what's simple enough for a management-type person running windows that's interoperable with linux".

Problems with SIP?

[EmptyHead]

I travel quite a bit and I've had problems with SIP hardware solutions when I'm in countries where the ISP's use satellite for their uplinks. Ping response time runs from 600-800 ms and the SIP devices get very choppy, remember Max Headroom? http://www.maxheadroom.com/

Skype's software works surprisingly well in these environments compares to software from other providers. I have not tried any of Skypes HW based options.

An engineer from one provider whose hardware solution I was testing and who was actually trying to be helpful said that my problem was with SIP's Jitter Buffer not being able to handle the ghastly latencies that I've been experiencing during my journies. If I hadn't already had problems with 2-3 other providers, I'd have thought that he was blowing smoke...

Re:Problems with SIP?

[CharlieHedlin]

It isn't the latency, but the jitter (the variation of latency). a 600-610ms or 900-940ms latency isn't a problem, but 600-800 is. Most decent sip clients can be tuned to support that, but the providers lock the settings down too far for you to do anything.

Re:Problems with SIP?

[EmptyHead]

I wonder if anyone can recommend some HW based (provides analog phone connection attached to a broadband connection) solutions that work well under such conditions where the latency is huge and highly variable.

I gave up a while back and started using Skype on my PC, but they aren't the cheapest option and have some strange payment options when travelling about. Sometimes they simply won't allow you to make a payment based on your location. This anti-fraud stuff annoys me, sometimes. They seem to forget that it's my money and there should be a mechanism in place for me to spend it.

Firewalls?

[Anonymous Coward]

I'm not sure but I don't think GnomeMeeting/Ekiga is clever enough to automatically punch through firewalls like Skype/Gizmo. Therefore users (ie grandma!) will be expected to alter their broadband router settings to open a port. Frankly, that's asking too much. It's also insecure.

waiting for wengophone2

[Anonymous Coward]

don't like skype because of closed source, p2p and not open?
keep your eyes on wengophone then: free, open source, supports msn, jabber, yahoo and other protocols, uses sip, can send sms, video calls, can handle conference (just up to 3 users for now), and it even costs a bit less than skype on skypeout. it only lacks the skype-in function and crypted traffic, but both will be integrated in near future. for windows, linux & mac for now, they're developing even a firefox extension and one for pda with wince.

Skype

[jevring]

Wow, that has GOT the be the LAMEST excuse ever for choosing sip over skype.
He gets crybaby points from me...

What about Openwengo?

[Juan Rey]

It's SIP, It's GPLed, multiplataform and soon multiprovider. Has anybody given it a try ?

Hmm... SIP of course

[guruevi]

Skype is a closed-source resource-eating protocol. SIP is an open, standardized protocol which projects like Asterisk use. I think telephony should be a PPP (Point-to-Point Protocol) and not a Kazaa-like P2P (Peer-to-Peer protocol). First of all: what information passes the supernodes? Can anyone see or analyze who you're calling, when and where? Second: what is the bandwidth usage? I can call SIP through 56k, can I call Skype as SuperNode on 56k?

So that's where my 10 GB cap went...

[spxZA]

I was wondering how I reached it so quickly, while downloading nothing [but the occasional update]. Yes, we in .za have 10GB caps!

Re:So that's where my 10 GB cap went...

[Malc]

I somehow doubt it. I work from home, run two Skype clients concurrently and often copy 1 GB video files to and from the office. I still have months where I use less than 10GB (accourding to my ISP).

Re:So that's where my 10 GB cap went...

[deroby]

BS. I'm running two skype accounts about 8 hours a day, every single day. And there are months where my total usage doesn't reach the 1Gb mark. I'm not saying that you are (actively) using up all the bandwidth, but if I where you I'd spent a little time to find out who is then (think spy-ware, ad-ware, virus, zombie-ware, etc) because it surely isn't Skype.

As for my little private opinion : maybe Skype doesn't really advertise as P2P and fully explains the 'potential overhead', but they don't hide it either. You just have to look for it and be sufficiently technical to understand how it works (see : http://www.skype.com/products/explained.html as a starter, I'm sure they have some kind of 'protocol-breakdown for dummies' too somewhere, too lazy to look it up right now but I'm sure I've read it in the past).

Personally I consider it a VERY small price to pay for the service that is being offered here, it works straight out of the box, is easy to use, and you surely can't call it a resource hog!

(disclaimer : I have no experience with the SkypeIN/OUT options, but some colleagues use it and seem to be quite happy about it.)

The only two things that might 'annoy' me occasionally is that the Skype homepage tends to address me in French whenever I log on to them (DUHUH, only 40% of Belgium speaks French as their motherlanguage), and (but that's hardly "their" fault I suppose) that about every week or so a 27-year old, aerobicizing girl is trying to become my buddy... As I have put my picture on my profile, I'm pretty sure they are bots and not real girls =)

(I have the privacy option that only people on my contact-list may contact me turned on, so "they" have to revert to this in order to be able to send me spam... First time I accepted such an invitation the conversation went something like this (I was sooo naive =)

Me> Hi there

Me> No offence, but am I supposed to know you ?

She> Hi, my name is Carla

Me> Hi Carla... [in the meanwhile checking her profile... NO YOU PERV, HER SKYPE PROFILE !]

She> yes, I'm from Brazil

She> You should meet me at my homepage, it's http: //www.hornysluts.ru /534538743/carla.html

Me> oh, that kind of homepage

She> Hi, I'm Carla

Me> Did you know the moon is made from cheese ?

She> yes, I'm from Brazil

Me> well, well, who would have guessed ?

[Add Carla to ignore-list]

FYI : Belgian ISP's have a 10 (sometimes 15) GB volume limit too, so welcome to the club =P

SIP = ! Video

[Anonymous Coward]

Skype has video, which is surprisingly usable. SIP does not.

Avoid becoming a supernode by blocking the inbound port, or by closing Skype.

Audience

[Splinton]

Skype is the only proprietary bit of software that I use, but I am reluctant to use another simply because the rest of the known world (known to me, anyway) are using Skype. So if I want to communicate with them, I have no choice BUT to use it.

I would desperately love to use an OSS version, but I can't do so without severely limiting my contact with my friends/relatives.

One Important thing....

[Toreo asesino]

I actually use Skype solely for it's paid-for services (SkypeOut, SMS, etc) as I live abroad, and don't want to pay extortionate rates for international calling.
This isn't covered in any SIP clients that I'm aware of, thus making this debate irrelevant for me at least. My only gripe with Skype for Linux is that they haven't ported over the SMS functionality yet - it, for me is a reason on it's own to use Skype.

Re:One Important thing....

[amorsen]

I actually use Skype solely for it's paid-for services (SkypeOut, SMS, etc) as I live abroad, and don't want to pay extortionate rates for international calling.
This isn't covered in any SIP clients that I'm aware of

It's certainly not convered in the client, but there are lots and lots of providers, and they'll work with any client. With Skype you're stuck with one provider. Can you even bring your old phone number to Skype?

Re:One Important thing....

[Toreo asesino]

Well, my point is that with Skype can call any land-line in any country at local rates, all natively supported by client, protocol, and provider seamlessly. I don't doubt it would be possible to do something involving SIP, but why bother when it's been handed to me on a plate?

I'm open-minded; if there's a package/client which allows me to call & text international numbers at local rates, and that just-so-happens to be running on SIP, then fine - I may switch over if it's any good. Otherwise Skype works just fine for what I need it for.

If I was doing Computer > Computer calls only, then we wouldn't be having this discussion of course.

Re:One Important thing....

[The_DoubleU]

Have you tried Gizmo?
It is a SIP client, supports Linux, Mac and Windows and you can buy credit to call landlines/mobiles and send SMS.
The SMS function works on the Mac but I presume it also works on Linux.

Re:One Important thing....

[amorsen]

Well, my point is that with Skype can call any land-line in any country at local rates, all natively supported by client, protocol, and provider seamlessly. I don't doubt it would be possible to do something involving SIP, but why bother when it's been handed to me on a plate?

What is so hard about typing in a server name, a user name, and a password?

Re:One Important thing....

[Micah]

I live abroad too, and have used both Skype and Ekiga on Linux.

Actually Ekiga with the diamondcard.us service is cheaper -- 1.7 cents a minute to the States vs. 2.3 cents with Skype. So you certainly have a choice.

Having said that, I still usually use Skype. I've had some sporadic trouble with Ekiga, and my GF uses Skype, and isn't really computer literate so I don't want to talk her through setting up a SIP client ...

Ekiga port for Windows?

[TheSync]

If someone would port Ekiga (http://www.ekiga.org/ formerly GnomeMeeting) to Windows, there might be some hope for SIP!

The key to Skype and SightSpeed (www.sightspeed.com) is that they are cross-platform and have solution to the NAT problem. But they are both non-standard. And they both work really well :)

Ekiga has a solution to the NAT problem using STUN servers, but until someone writes a Windows port for it, there will not be massive usage of Ekiga.

Re:Ekiga port for Windows?

[Anonymous Coward]

What's the point of pointing Ekiga to Windows? Just so that everyone you know can use the same client, just like with Skype? What's wrong with simply using the same *protocol*? Like, download one of the many free or shareware SIP phones for Windows, and use that to connect to Ekiga. Some of then (like SJPhone (the only one I played with on Windows)) support STUN too.

You guys are kidding, right?

[glomph]

Skype is a closed secretive disaster. The community RANTED when MSN/AIM/Yahoo messenger played games to cut out client choice (Gaim, Trillian, et al.). If you want simple, use Gizmo ( http://www.gizmoproject.com/ ) which has a very economical and functional interface to the regular phone system (POTS). Even cheaper, try http://www.voipstunt.com/ or http://www.freecall.com/
All of these are street-legal SIP, and you can use any SIP-capable device you like, or use your computer if you want to.

And of course you can use Asterisk ( http://www.asterisk.org/ ) which is best of all!

Skype belongs in the shitbin of history. Closed systems suck.

Re:You guys are kidding, right?

[Dantu]

Skype is a closed secretive disaster..... If you want simple, use Gizmo ( http://www.gizmoproject.com/ [gizmoproject.com] ) which has a very economical and functional interface to the regular phone system (POTS).

Tried that, the POTS interface was totally useless (at least to the locale I was calling, in a rural part of Canada). I was lucky to catch two-thirds of what the other party said to to buffering/latency issues. Skype can be a little choppy at times, but is generally quite usable.

Oh, that's nice.

[Moofie]

"the very idea of my PC having its resources tied up for someone else's phone call is frankly maddening to me."

But having somebody else provide the same service for you is no more than your due, right, Your Majesty?

A good SIP phone is hard to find...

[sco_robinso]

My business of approx. 40 people recent moved from a fancy, very expensive centrex phone system to a Asterisk based IP phone system. Overall, our results have been very positive. Part of our plans, however, were to have approx. half of our users use Softphones. We have tried probably about 2 dozen IAX, SIP, and proprietary softphones, and to this day we had not found a single one that worked very well, exactly how we wanted it to. Our requirements were fairly simple:

1. Had to be able to connect to outside phone numbers, not just other clients on the network.
2. Had to work with our IP-PBX (Asterisk). This ruled out alot of the good, proprietary clients like Gizmo, Skype.
3. Since alot of our users travel ALOT, the phone had to work flawlessly through firewalls. Although we can configure the firewall on our end, when our users are at hotels, etc, they couldn't connect. This pretty much ruled out SIP altogether in favor of firewall-friendly IAX..
4. Voice quality had to be excellent. Too many users would be using it as a primary phone.
5. Cost wasn't an issue, if the phone was good.
6. The phone would be used by ID10T's. It had to be simple and intuitive.

All I want to say is that although there are a ton of them out there, finding a good softphone is harder than you think. There's lots that fit indivdual users needs very well (I use skype with skype-out and it works great). The best we had found overall was idefisk (asteriskguru.com). Although, it leaved alot to be desired as far as voice quality goes. Still, we're searching for a good softphone for our mobile users.

Re:A good SIP phone is hard to find...

[Anonymous Coward]

for goodness sake get hardphones they are always going to be much better

u will always have quality issues with remote softphones cause u normally don't have influence over the network they are connecting across. (softphone via wifi in an airport with probably 100 other users moving about google maps is never going to cut it)
if u have to.... http://www.xten.com/ is a personal favourite... but buy polycoms for the office

Re:A good SIP phone is hard to find...

[sco_robinso]

Yes, over the past year I have very quickly come to learn this. We do use hardphones whenever possible. Given our particular office setup, it was preferable to have some of our users on softphones. But most of them didn't even like the whole concept anyways, and we got such a backlash, that we bought a few extra hardphones.

And yes, I've tried xten/eyebeam. It was our favorite amongst the SIP softphones, but the issue of SIP not being very firewall-friendly stopped us from adopting it for mainstream use.

Re:A good SIP phone is hard to find...

[mdudzik]

...."Had to work with our IP-PBX (Asterisk). This ruled out alot of the good, proprietary clients like Gizmo, Skype."

Gizmo 2.0 for Mac and Windows does work with Asterisk. http://support.gizmoproject.com/FAQs/asterisk.php

OMG SHARED RESOURCES!

[Blakey Rat]

Granted, this is not always the case; however, the very idea of my PC having its resources tied up for someone else's phone call is frankly maddening to me.

This same guy probably runs BitTorrent and the Blizzard Downloader for WOW with no complaints.

What it comes down to is that Skype plain has better sound quality. It sounds better and with less latency than all the competitors I've tried. Period.

Warning: Gizmo Installs Spyware

[Anonymous Coward]

The Windows XP version of Gizmo silently installs some crapware called Bonjour. This pos will spawn yet another background process which then tries to communicate with external servers. Gizmo project hacks: "Are you listening?". This is a very, very, very bad practice! The crapware can be disabled, and you can find out how by searching the Gizmo project forum.

apples vs oranges

[Anonymous Coward]

I think that comparing Skype vs SIP is like comparing apples vs oranges.

SIP is just a session protocol, so it has nothing to do with audio quality (compare codecs then: ilbc,speex,g723,g729), free calls (compare services skype,vonage,people call,..) or applications cpu usage.

Thanks for the differences; there are even more

[postbigbang]

Thanks for pointing out the obvious thing that people forget. Let me go further and say:

1) Skype is closed and a single metamodel that's been implemented nicely and virally (not that it matters)

2) SIP (and ENUM) are perilously prone, not because they're protocols, but how the protocols are implemented, to shenanigans. SIP is natively text, and ENUM is a DNS method that's prone to spoofing and other problems. For now, Skype wins only because few people know how it works at its deepest levels.

3) Skype isn't as extensible as the SIP/ENUM combination, and it makes one dependent on a single (if diverse and highly peered) network.

4) SIP and ENUM don't care about the service and are largely service neutral (some coming problems, here, though, as it doesn't do nice things like embue codec choices, encryption/authentication means, and other security niceties).

5) Skype is one closed vendor, very few business partners, while SIP is a technological infrastructure that invites whomever to do whatever.

Lend a helping hand.

[suparjerk]

Upset about it tying up your system's resources?... ehh. I don't have hard evidence to support this claim, but I'm pretty sure the average desktop CPU doesn't operate at 100% most of the time. Neither does their "comfortable" network bandwidth (i.e. more could be being done without noticeably adversely affecting anything). If you can skim a little off the top to help someone else out without actually interfering with what you need to do with your computer, I don't see that as too much of a problem.

Think of it as going into a building and holding the door open for someone following a little bit behind you.

If you're really that concerned that your computer should never be used to help anyone but yourself, I'm sure you could figure out some way around it. If you're like most other people, I bet you could get away with simply lowering the priority of the process...

Whatever you select

[Z00L00K]

will cause some drawbacks. The SIP protocol is unfortunately not very firewall-friendly and may not work well without some firewall hacking. The firewall problems are mostly due to the fact that it's relying on multiple UDP ports for the voice transmission. Skype on the other hand seems to be bypassing firewalls with ease.

A few downsides with Skype are that it may act as an intermediate for other callers and it is relatively CPU-hungry.

A better protocol than SIP is actually the IAX2 protocol (Inter-Asterisk protocol v2). At least it's better from the firewall point of view, but has the drawback of not being very widely supported outside of the Asterisk domain.

Better reasons

[VincenzoRomano]

Maybe there is some other reason to choose SIP. It's openness (as in OPEN).
You can choose you favouite service provider (even more than one) and your favourite software (even more than one).
Yet, if you dare enough, you can run your own service or write your own SIP client.
Nothing of this can be done with Skype (and similar initiatives).
Some more interesting considerations about Skype can be found at here, written some time ago by Bob Cringely.
And if you find these latter things interesting, you'd give a look to this project.

Skype doesn't use resources if it's not running

[Matt Perry]

One tidbit of information that most people are not likely aware of is that when you install the Skype client, it will drain system resources by running as a supernode from time to time.

Cry me a river. Shut down Skype when you aren't using it if you don't want to share your bandwidth. The system works because of tradeoffs and people acting as supernodes.

SIP providers and Skype

[tttonyyy]

Well, the problem with SIP and Skype is NAT. The phone/computer doesn't know it's WAN IP to establish connections with other phones, and there aren't necessarily inbound UDP ports open to route UDP traffic to the phone.

NAT routers temporarily accept inbound UDP packets on a port when there has been an outbound UDP packet on that port (aka UDP pinholes). So you get a working UDP "connection" (well, stateless ;) ) both ways once you've estabilished an outbound connection. For VoIP with both users behind NAT, however, this is unlikely to work.

Skype gets around this by using computers that aren't behind NAT to route traffic between two phones that are behind NAT. So if everyone was to block this behaviour, Skype just wouldn't work for NAT users. It requires some community spirit (even if this is unintentional on the part of the user).

SIP systems often employ STUN servers that allow a phone/computer to query the server to find out what its WAN IP and NAT type are (and use the query itself to open up temporary UDP inbound ports on the router - something that works with all NAT types except symmetric).

There's a description and some pretty pictures of how STUN works here: http://www.newport-networks.com/whitepapers/nat-tr aversal3.html

In addition, SIP is also an open protocol, so there is nice free open-source software available (Asterix) to allow you to set up your own home switchboard (calls from different outside lines can be routed to different phones - IE, whenever your daughter's boyfriend calls, it can be routed to ring her VoIP phone). Skype is proprietry so you won't get any customisable features like this.

So really, SIP is the way to go if you're a supporter of open standards, and Skype if you want to follow the headless masses. :)

Re:SIP providers and Skype

[Anonymous Coward]

Actually, Skype uses STUN, too. It's just that STUN very often doesn't work, especially if there's an aggressively UDP-blocking firewall in the way, or the NAT isn't full-cone. Only in that case are supernodes used.

http://saikat.guha.cc/pub/iptps06-skype/

Remember that one of the big advantages of Skype is that it's freakin' hard to block or filter, something you most certainly can't say of SIP. I've seen Skype clients worm their way through some of the most baroquely-routed and firewalled networks I've encountered. That's a great thing if your ISP has it's head up it's *ss and specifically tries to block or impair VOIP traffic (yes, Verizon, I'm looking at you). Of course if it's your job to enforce a network security policy that doesn't include unlimited office Skype use, then its much less than great.

Re:SIP providers and Skype

[BenFranske]

Or you could use IAX which has many of the benefits of SIP without the NAT headaches...

Re:SIP providers and Skype

[3.5 stripes]

If you do symetric udp connectivity, you can be behind a NAT without to many issues, all that needs to happen is the software needs to use the same udp port for both outgoing and incoming calls.

Been looking into it, as I'm setting up an Openser server for VOIP connectivity.

Gripe With Skype

[RAMMS EIN]

My only real gripe with Skype is that the protocol is secret. This means that no alternative implementations can easily (or even legally, depending on jurisdiction) be created. Want to create a client that doesn't need a GUI, implement one in hardware, make one for OpenVMS, or create one that is verifiably free of malware? You can't without the blessing of Skype, Inc.

I refuse to use secret protocols or file formats wherever feasible, and it's definitely feasible in this case.

Re:Quality

[jeffstar]

I tried several different VOIP programs some of which were based on SIP and set up fwd accounts and the like but in the end we chose skype for one reason only: the call quality was superior. Most of our calls are placed over 802.11 networks in remote areas that have no cell phone coverage and use satellite for the internet connection.

Some calls have to make it through seven access points and then out over 800ms of latency and skype calls actually still are very usable and even sound good. I don't know how they pull that off. I'm willing to put up with being a supernode for that.

Why skype?

[dlichterman]

Because ID10T's can install it. Its cross platform and easy to use. We use it to talk to my Cousin in Thailand or Korea. My Aunt and Uncle have it in Oregon. It is also able to punch through firewalls and NAT problems extremely well BECAUSE THEY USE SUPERNODES to connect the call.

Also here is a good "Whitepaper" on the skype protocall
http://arxiv.org/ftp/cs/papers/0412/0412017.pdf

Overlay Network

[RAMMS EIN]

About the only advantage Skype has over the competition is that it Just Works in a variety of firewall and NAT scenarios. About the only trick it uses that no open protocol system uses (to my knowledge) is a peer-to-peer proxying network that is used if direct communication between peers is not possible. It seems to me that such a network can easily be implemented in a generalized (i.e. protocol independent) fashion.

I've been thinking in the direction of a TUN device connected to a proxy node with a globally accessible IP address, where any port being opened on the TUN device is also opened on the proxy node, and all traffic sent to the proxy node is forwarded to the TUN device (effectively creating the illusion that the TUN device is a network device of the proxy node). This system can be largely transparent to applications, except that they have to use the globally reachable IP address instead of whatever other IP addresses the machine may have (e.g. the same problems that always occur when a machine has multiple network interfaces).

This scheme could be extended with little effort to include hiding of the real source of data and encryption, thus providing a degree of anonymity and confidentiality, all transparent to applications.

So far, it's a nice dream. I started mucking around with TUN/TAP, but I couldn't see any of the packets I sent to the virtual device, and I couldn't find good documentation to tell me what I was doing wrong and what I should have been doing instead.

There's lots of bogus anti-Skype FUD

[billstewart]

I've never been sure of why there's a lot of anti-Skype FUD out there, but there is, just as there was a lot of FUD about the Scary Security Risks of USB flash-drive dongles. I think it's mostly columnists copying each other's memes so they've got something Serious to write about.

Skype doesn't use a lot of bandwidth, so even if you're running in supernode mode it's not going to make a big difference, except maybe if you're on a home DSL with 128kbps upstream bottleneck, and the FUD's targeted at businesses and universities that have much larger connections (i.e. places that make decent supernodes.) It's good to hear that Skype's doing some consulting and proxy-server work to help manage that kind of business.

Skype does have the problem that they're a rabidly closed-source company with rabidly closed-source protocols, so it's partly their own fault. In contrast, BitTorrent is wide open - so if you want to do things to reduce its bandwidth consumption, you can, though it's also designed to get around firewalls whenever it needs to.

Re:There's lots of bogus anti-Skype FUD

[GreyPoopon]

Skype doesn't use a lot of bandwidth, so even if you're running in supernode mode it's not going to make a big difference, except maybe if you're on a home DSL with 128kbps upstream bottleneck, and the FUD's targeted at businesses and universities that have much larger connections (i.e. places that make decent supernodes.)

Uh, if the supernode mode is enough to cause performance problems with a single user over a 128kbps upstream connection, it's likely to cause some noticeable problems at a business with thousands of users running Skype -- even if the connection to the internet that they share is a very large one.

Use Asterisk plus SIP endpoint of your choice!

[Chembal]

Just so you know, I started with Skype, and it works just dandy. If it drains away my resources, I haven't noticed it. But, I've recently had the pleasure of installing asterisk at home, and it is the way to go! If you install and use Asterisk, you have the widest choice of phones (including soft phones) and VoIP endpoint providers, and you have the flexibility of changing your mind about any one of those choices at any time without disturbing the rest of the system. In my recent conversion, I converted the whole house to use Asterisk without changing any of our phones. My wife doesn't notice the difference - she just calls normally and it works. But, behind the scenes, I can selectively route different calls to different networks - hard wired or VoIP - to take advantage of whatever route I decide is the best. If any one of those routes starts to irritate me, I can change it without affecting the rest of the system. Try that with Skype.

Now, a common argument you might get against this approach is that it's unneccesarily complicated and requires a dedicated machine. Well, it may be partially true, in that it's more complicated than installing a single SIP or Skype phone or softphone, and the best (IMHO) approach for an install takes a surplus box; however, the TrixBox distribution gets you up and running awfully fast, and can be installed onto a crap machine (I'm using a celeron 500). Follow the How-To here. The flexibility is worth it. And, if you have a decent net connection and VoIP provider, the call quality even for VoIP is outstanding.

Other advantages are flexibility in call routing. I currently have a digium TDM400P card hooked up in my install, with one module hooked up to the phone line, and the other module hooked up to all my analog phones in the house. (I'll eventually replace some of the analog phones with some nice IP phones when I have the cash.) I could just as easily add SIP softphones connected to Asterisk, if I wanted, but normal phones seem more natural to me, and it's cheap to do with the TDM400P card. I have three inbound and outbound trunks set up, one using the land line, one using VoipJet for long distance over VoIP, and one for calls in from and out to the Free World Dialup SIP network. I have my dial plan set up as follows:

Any calls coming in from either my old PSTN landline or my Free World Dialup account are routed to my dialplan, which during the day (6AM to 11PM) rings the analog phones. If the caller is blocking caller id, it forces them to enter their phone number first before ringing the phones. At night, (currently defined as 11PM to 6AM) callers are sent to a VRU, which asks them to hang up if they're a phone solicitation, press 1 to actually call us, or 2 to send the call straight to voicemail without waking us up. In either case when it rings the phones, it will go to voicemail if we don't answer. That voicemail can be retrieved either by the phone, by secure web interface, or currently I also have it email me the wav file of the message.

For outgoing calls, I have it set like this: If you dial a seven digit number, a toll free number, 911, or use a 9 prefix before a long distance call (in case my network connection is down), it dials out through the land line. If you dial a long distance number normally (using just 1 + area code + number, or 011 + country code + international number), it routes it through the IAX2 trunk to VoipJet and saves us tons of money. If you dial a 8 or 393 prefix before the number, it assumes you want to call a FWD number, and routes it out the IAX2 trunk to FWD, which would be a direct SIP to SIP call for free.

In summary, it works awesome, and I had the whole thing working in a basic way (PSTN + analog phone + VoipJet trunk) in one Saturday morning. I had rerouted the whole house's phone system and revam

Considerations

[VincenzoRomano]

Maybe there is some other reason to choose SIP. It's openness (as in OPEN).
You can choose you favouite service provider (even more than one) and your favourite software (even more than one).
Yet, if you dare enough, you can run your own service or write your own SIP client.
Nothing of this can be done with Skype (and similar initiatives).
Some more interesting considerations about Skype can be found at here, written some time ago by Bob Cringely.
And if you find these latter things interesting, you'd give a look to this project.

Re:Considerations

[CharlieHedlin]

Having written a sipXtapi application and the SipxTapiDotNet wrappers you better be quite daring. If you are it can be very rewarding.

Quick security point

[Anonymous Coward]

I don't think this has been brought up yet - SIP has NO standard authenticity to its caller-ID unlike Skype. I can just go online, and pretend to be your Mom, best friend or your employer, just by asserting the FROM address, just as one can with e-mail. E-mail has an excuse - it was invented in a fairly closed internet where there was a lot of mutual trust. There's no such forgiveness for SIP.

Re:Quick security point

[Anonymous Coward]

Thats not a SIP problem, thats a fundamental flaw in the design of your SIP agent. I work on a commercial switching product that has SIP subscriber support. The system authenticates your user name and password and sets the Caller ID based on the subscriber name and number entry in the subscriber database, not based on what is in the SIP headers.

Re:Quick security point

[Anonymous Coward]

Fine, but that only works in one network. I'm at sipprovider-alpha, and I receive a call from user@sipprovider-beta.org , a completely separate organisation to mine - how do I trust that that call is from a sipprovider-beta user? It really is as sloppy as e-mail, and there is no excuse. Jingle/Jabber is where it's at for secure IM and VoIP.

Skype works well, SIP works badly. End of story.

[porttikivi]

I have called a couple of people today with SkypeOut for international calls. I have chatted with individuals and on the company grpup chat. I am behind a firewall in a private address and so are all my buddies. All this is encrypted, except the POTS part of calls. I can immediately call 7 million of online Skype users. I have SkypeOut, SkypeIn (my GSM phone is in another country currently, I have transferred my calls to SkypeIn), I have Skype voice mail, I can send voice messages to any Skype users, I can send/receive SMS, and whatnot...

I also have Gizmo and X-lite and some other SIP clients installed, and Gizmo even allows free calls to many POTS phones. But for me these are worth testing only. I have trouble finding people's SIP addresses, if they have any, and then trouble making the clients call each other. I have trouble with firewalls and private addresses. There is no encryption. There is only a limited basic service. SIP sucks big time, and needs to be forgotten, before a million engineers waste their career on it. Come up with something better instead, if you want to have an open source competitor for Skype. Jabber, Jing, whatever, maybe they can have a try.

Sip? No. Skype? No. Jingle? OK.

[Baloo Ursidae]

Why go with SIP or Skype when Jingle integrates more sanely into existing infrastructure?

Nice troll

[metamatic]

You might get a few people who don't know that Bonjour is simply multicast DNS used to provide chat on your local network.

1 reason why Skype sucks

[Anonymous Coward]

The one reason why Skype sucks is this:

Poor user control over Internet usage.
I have two internet connections and I would like to use Skype on
just one of them while keeping the other one as my default route.

Even when I configure Skype to use a proxy, which should direct it's
traffic to just one ISP, I still get Skype traffic all over my other
ISP link (the default) which is really bad because that link is
reserved for other traffic.
The proxy setting simply works as if the setting was "a recommendation".

To my query to Skype their support has not
even bothered to reply for months and months now.

This is so arrogant of Skype I'm taking now every opportunity
to tell people what they are really installing when they get Skype.

But hey.. what do you want.. the same people who wrote Kazaa, write
skype - I guess it's normal practice for them to "know better than
the user"...

SIP is not a well designed protocol

[Anonymous Coward]

SIP is not a well designed protocol - it's a head-on collision of techniques from SMTP and HTTP, often with several equivalent ways of expressing the same thing. And the protocol authors put very few size limits on things. SIP has "buffer overflow attack" written on it in large red letters.

I use several Asterisk systems in my VOIP net, I use IAX, not SIP, to hook 'em together and punch through firewalls and NATs.

As for voice quality - SIP is a call setup protocol. The voice or video is carried on an entirely different protocol, RTP (and, its often unimplemented partner, RTCP, which has nothing to do with TCP)

No matter what protocol is used to carry the voice, delay (and jitter) will cause there to be a delay. Skype has no magic bean to evade the march of time. The software in the receiving phone has to put things back together into an audible stream. Some receiving software is not even worthy of the word "crap". Some receiving software is very good, receiving engines even have good algorithms for paching over the gaps left by missing packets.

There are reasons to use closed SKype

[sideswipe76]

To the utter disdain of companies like Comcast and many telecom people in China, no one has truly figured out how to discern that there is actually skype traffic on their network much less block it -- this goes for everyone from a nosey IT admin, the govt, or an unfriendly ISP. On the otherhand, Comcast has put the kabosh on SIP from Vonage because it is easy to identify. Skype should continue to improve on the efficiency and stealth of their protocol and improve the features of their client. Sadly, I think with eBay now owning Skype they may have lost that innovative spark.

Have your cake and eat it too

[DumbSwede]

Install Skype but delete if from the startup list. I use AdAware's TeaTimer app which forces the apps to ask permission to alter system settings, so I just had to say no. Skype installs, but will only be grabbing resources after I actually use it, and then only if I don't kill the app after I'm done. Actually not using Skype at the moment, using Google Talk and Gizmo. Learning to realy love my Nokia-770

Re:Have your cake and eat it too

[mieses]

Tapioca, Gtalk, and Gizmo do not support true SIP connections on the Nokia 770, even though they are "based on SIP"?

minisip is trying to update their client for maemo 2.0 (nokia 770):
http://lists.minisip.org/pipermail/minisip-users/2 006-July/thread.html#1175

i plan replace my office phone with a nokia 770 once a SIP client is available.

Typical.

[SanityInAnarchy]

Happens with entirely too many things. Google is about the only one that I like. iPod, MySpace, PowerPoint, Tivo...

So yes, people sell "Skype headsets" or "gTalk headsets", and we don't notice when there start being "Xbox Live headsets" which actually use a different plug. "PowerPoint" remotes. "iPod" cables. MySpace as a noun -- not "My MySpace page", but "MySpace: <url>".

Language these days is really getting abused. I don't know how recent it is, but it certainly feels Orwellian. Keep oldspeak alive!

Open and working

[Anonymous Coward]

XMPP and GoogleTalk

min info, no SN knows enough to analyze, low BW

[cbhacking]

Supernodes are simply used to establish a connection between two computers so they can open a conversation. At a guess, this involves the IP addresses, Skype ports, and possibly usernames. None of that is particularly private info, though if you REALLY don't want people to randomly develop the ability to know what users 'you' (your username) called, you may be SOL. (If this really bothers you, why are you on the Internet at all? It's not exactly private...) The encryption is end-to-end; FWIK supernodes cannot compromise the encryption and listen in. Since supernodes change all the time, it's highly doubtful that any given SN can obtain enough info on you and those you call to make very much of it. I don't know about you, but if I Skype 10x in a week, that's a lot.

Bandwidth usage is extremely low. I've read that Skype's codec will work with as little as 8kbps/channel, though the quality loss is noticable then. I have personally used it on a shared (multiple computers all in use) 56k line with no problems, quality comparable to a decent cell phone. You might not be able to run as a supernode with 56k - I don't know what the bandwidth needs for that are - but it desn't matter, because there are literally millions of other Skype users, and plenty of them are supernodes. The client works FINE if you are never a supernode, which is good... people behind firewall, perhaps anybody behind NAT, cannot be supernodes.

My experience with Skype and Gizmo

[bdwoolman]

I was a fairly early adopter of Skype. I downloaded 1.0 and loved it. This was about two years ago. I'm from the United States, but currently live in Europe and like to call home. I have a very good broadband account and Skype worked a treat... I really liked it for Skype Out, since I could call my 90-year-old mother on the landline and let her talk away. Skype worked great for a while. But after an upgrade I began to have terrible technical problems with it. I upgraded my soundcard driver, as Skype technical support instructed. Indeed, there was a complex list of tweaks and file replacements that came from Skype customer service. Clean installs, driver upgrades, registry edits. It was a nightmare -- even for somebody who usually takes mild pleasure in working through a computer glitch. All to no avail.

I hit their forum with some well-crafted questions and one kind soul finally had mercy (and the decency) to tell me that the North American Gateway was having difficulties and was giving Skype Out (the paid PC to phone service) a bad case of hiccups. I had but to wait and my service would work. (Had the company been honest with me I would have been spared hours of pointless geeking around.) I waited a couple of weeks, meanwhile paying the Norwegian telephone monopoly their pound of flesh for the few calls I needed to make, and tried again. Still the same old interference. I was not happy with the Norwegian telephone monopoly's long-distance rate card, so I downloaded Gizmo Project. It installed very easily and configured itself. The sound quality is a hair lower than Skype's at its best. But really they are on a par. But I find that Gizmo is extremely reliable. I would get dropped calls with Skype. Not so with gizmo. Note: I tried Skype out a few months later and still had the same screeching interference. It was worse for my recipients. But I could hear it.

In all of my reading about Skype --- I was all over their documentation trying to solve my problem --- I never tumbled to the fact that they were using my system in a distributed way. Not that I particularly mind that sort of thing if I am made aware of it. I am happy to share bandwidth as part of a peer-to-peer community. I mean, I'm as happy to seed a Linux distribution as anyone. I am sure that somewhere Skype lets it be known that it uses your resources. And perhaps they are right up front about it and I just missed it.

Okay, this has been noted, but it's worth saying again. Even torrent client software lets you choose your level of participation. If you want to be a dirty leech (and you can live with yourself) then you can configure the software accordingly and be a dirty leech. But Skype not only doesn't tell you, they also don't give you control.

But here's the kicker. Recently I downloaded a new version of Skype at the behest of an old friend who had installed it on his Mac in California and ordered a headset. We hadn't talked in years, although we had been in e-mail communication, but I was able to have a palaver with him Skype to Skype. There were no technical problems and the sound quality was excellent. Now, as I said, I learn on Slashdot that Skype is sucking bandwidth and performance. I was considering trying again with Skype Out since their service worked Skype to Skype so well. But now I think I'll stick with Gizmo Project.

Skype has been running as a TSR since I installed it. And I have noticed some performance degradation recently. I suspected it might have to do with Skype -- especially since I get a "Range error" message that is apparently due to my dual monitor setup. I generally don't like TSRs. Now I know that Skype is Skyping me as well as the telcos and it's buggy. It would have been polite to tell me. I HATE rude software. Time to hit MS config and remove the booger from the starting lineup. You're on the bench Skype. I will call you up when I need you. (FYI I went around the block with the "range error" message. Some guy in Japan with a kludgey patch. His site was down.

Ask Phil Zimmermann....

[Kernel Kurtz]

...what he prefers to support in his Zfone VOIP encryption project and he says (from the FAQ);

"Q: Does Zfone work with Skype?

A: No. Skype uses a closed proprietary protocol, which they do not publish. That makes it hard to make Zfone work with it. Skype does not interoperate with the rest of the VoIP industry, which is built on open standards. I decided to follow the industry standards."

Given the likelihood of government eavesdropping (without a warrant of course) on VOIP calls, this is worth considering.

The trouble is that SIP is a crap protocol.

[kholburn]

I would prefer an open standards solution but the trouble is that SIP and H323 are really crap protocols.

1) You have to open hundreds of special ports. Which makes forwarding this stuff a nightmare and means you have to open all this crap in your firwall.

2) Each company uses different ports. Ports don't seem to be a part of the standard.

3) The source and destination address are in the data not in the headers (how hard is it to use standard IP source and destination addresses?) Which makes any system with NAT a real pain when it should just be transparent, it should just work.

At least skype works with almost any firewall and if you have a firewall, almost any firewall skype will never make your system a supernode. That wasn't that hard was it?

Some group should create an open standards base protocol for sound and video that works properly.

Some of the issues about skype payments are going to be a problem with any company say gizom or wengo.

Re:The trouble is that SIP is a crap protocol.

[laptop006]

1) You have to open hundreds of special ports. Which makes forwarding this stuff a nightmare and means you have to open all this crap in your firwall.
No. You have to open two. The control port & the data port. The fact that RTP (the data port) is usually set to use any port in a large range is irrelevent.

2) Each company uses different ports. Ports don't seem to be a part of the standard.

No they don't, SIP and H.323 have a standard port, RTP is dealt with a-la the Sun RPC portmapper.

3) The source and destination address are in the data not in the headers (how hard is it to use standard IP source and destination addresses?) Which makes any system with NAT a real pain when it should just be transparent, it should just work.

This is becuase the two connections (data & control) may be to two totally different machines. eg a PBX that doesn't handle media would result in two phones with the data connection between each other and a control connection to the PBX.

Re:The trouble is that SIP is a crap protocol.

[kholburn]

1) You have to open hundreds of special ports. Which makes forwarding this stuff a nightmare and means you have to open all this crap in your firwall.

No. You have to open two. The control port & the data port. The fact that RTP (the data port) is usually set to use any port in a large range is irrelevent.

Not true. I was talking about external firewalls not personal software firewalls. All those ports have to be opened on external firewalls unless you do complex client configurations. If you are running a layer 4 firewall with SIP tracking it might do this, the trouble is that some parts of SIP ahs H323 are not easily exposed at the router firewall because of the IP addresses in the data.

2) Each company uses different ports. Ports don't seem to be a part of the standard.

No they don't, SIP and H.323 have a standard port, RTP is dealt with a-la the Sun RPC portmapper.

And not all companies use the same port.

3) The source and destination address are in the data not in the headers (how hard is it to use standard IP source and destination addresses?) Which makes any system with NAT a real pain when it should just be transparent, it should just work.

This is becuase the two connections (data & control) may be to two totally different machines. eg a PBX that doesn't handle media would result in two phones with the data connection between each other and a control connection to the PBX.

How hard is it to put the correct addresses in the headers to the machines you want to send the data to?

Skype is a viral network/numbers dont lie

[Anonymous Coward]

Reading this thread, I thought I'd post some very pointed numbers, which are real, relevant and probably unknown to some of you.
Skype TCP

Where our client are using Skype and are "clients" of conversations - 2.9k of bandwidth is consumed.
1.1 incoming/2.8 outgoing, total of 32 connections

Where our client are "servers" of conversations
10 active users, 39.7k incoming/63.9k outgoing. Total of 705 connections.

Without going into boring "gory" details, we see an average of 750 active connections per user using Skype-p2p udp. This is less than 160k overall in/out from a traffic perspective. We can sit there and watch the active connections zip to several thousand connections per user (not as a Skype hub-to-hub, or supernode).

Skype is JUST like is predecessor, viral in nature, aggressive in its connections. It would be preferable if Skype would limit the number of active connections to tone down its aggressiveness lest they go the way of Kazaa. As an ISP, we are considering banning hub-to-hub (we can do this centrally) and limiting the bandwidth and connections of users for Skype, as we get tired of answering their support calls only to see their problem is their PC can't handle some awful number of connections and surf the Internet too. Before we start out on this, we need to think it through from a procedural standpoint, because we know some folks "pay" for the service. In my mind it's OK to limit to "viral" effect to a reasonable limit, as it does wreak havoc on individual connections, and does hamper the ISP's ability to deliver a functional connection to the end user.

Skype reverse engineered (March 2006)

[SaberTaylor]

fun read:
http://www.blackhat.com/presentations/bh-europe-06 /bh-eu-06-biondi/bh-eu-06-biondi-up.pdf

SIP already better than Skype

[Jump]

SIP, in my opinion, is already better than Skype. First it is free in the sense that any company can start offering SIP. Large companies can even
offer it two its own empolyees. Second, because of Skype, prices dropped a lot during the last year. Now I can have a free landline number and free registration. The phone calls are either free for a monthly flat rate fee, or as cheap as skype. Since I moved to SIP from (www.sipate.de), I saved a lot of money. Enough to pay for the new equipment and more. I now think about buying a wifi phone, because we get free wifi in town.

This is great, because there will be no difference between mobile and landline phones anymore. And calls are basically free already today.
So why should I use Skype? With Skype I pay for the number and calls are only free for US citizens (or skype to skype). With SIP I have free calls
in 15 european countries and of course sip to sip. And I can use multiple SIP providers on a single phone, so I'm not locked in by one particular
SIP company, although I like sipgate so far (they still seem like a startup company to me, not like the big telecoms).

So, if you have internet over cable or can have nacked DSL, go for SIP!

Re:SIP already better than Skype

[kholburn]

And can you have more than one SIP phone behind a firewall with NAT?