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Sprint Moves Phone Network to IP
Ryan Barrett writes "Sprint announced that it has 'begun transforming its telephone network so voice calls are transmitted in packets.' AP article here. Combined with a recent /. story about Telus doing the same thing, this sets an interesting precedent. Many telcos already use packet-switching to handle a significant chunk of their calls. Is this the beginning of the end for circuit-switched networks?"
Hello, Sprint? This is Telus. You stole our idea you son-of-a-bit....
Reminds me of that old Dogbert Joke about having a Tilde in the phone number. I wonder how long it will be till them move to IPv6, won't that be a joy to dial.
Sorry about the writing. Robot fingers, you know? Cliff Steele in DOOM PATROL #23
The beginning of the end started when the equipment manufacturers started producing boxes that allowed VoIP calls to have the same quality as circuit-switched ones. We all probably make a lot more IP calls than we are aware of.
The quicker companies do this, the better it will be for their margins - this news from Sprint probably doesn't mean much for their users, but their shareholders should be happy. The cost of carrying VoIP is much lower, which is what allows those calling card companies to stay in business.
its going to cheaper in the long run for my telco service nah probly not they probly still charge the same amount and pocked the rest as always.
The article didn't state that Sprint was switching to an IP based network, just a packet switched network. Is this actually going to use IP? A quick google search brought up no mention of IP (but I'm also lazy, so I only read the first page of links).
"However," replied the universe, "The fact has not created in me A sense of obligation."
..will make it cheaper for Sprint to grow its network..
, unfortunately, monthly fees will rise with 25% due to the *better* services that'll be provided....;o)...
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Call me on 3ffe:0501:0008:0000:0260:97ff:fe40:efab, see you soon.
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so they will be laying new lines for this?
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It is nice to hear that Sprint will be moving long distance telephony into the next generation. It sounds like it will save them a bundle and help them manage growth. Still, I am languishing with an analog copper-pair connecton to my home phone. Will someone (anyone) drop a fiber into my backyard?
I really can't see an end to circuit switched networks any time soon. The switch to Packeted data is fine for most commercial traffic, but there are a few areas that will continue to require "locked in" circuits as opposed to packet buffering systems.
There is a lot of value in the use of packetized data. More "lines" over fewer trunks is just one of them, and for your average, everyday user, they will not notice the difference.
On the other hand, certain timing based encryption schemes will have to remain on locked in circuits to function. The latency caused through the use of packet buffering regardless of how slight, may be enough to cause a "handshake" failure, or just spew unintelligable garbage.
Of course, as encryption systems become more and more robust the need for "hard lines" will start to dissipate.
I for one welcome our new packetized telephone overlords...
krystal_blade
It will be easy to motivate our fellow man; there is hardly anything people treasure more than not being annihilated.
The network will still be switched at a local level, I suspect (even if the future telephone exchange, instead of switching analogue circuits, works more like an Ethernet switch). With so much copper going from the home/office to the exchange, it's likely to continue to be in use for the last mile for some time to come.
Trunk switching has been multiplexed for decades already. Previously, it might have been multiplexed by FDMA (frequency division), and now it looks like they are moving to IP based (or similar) to route calls through exchanges. The end user won't notice the difference. It's unlikely that the call routing will be done over the public Internet.
The trunk network can already run out of capacity - you do not now have dedicated bandwitdth and never had dedicated bandwidth over the trunk network (ever got the 'All circuits are busy' message?) A packet based trunk network is no less secure than the existing trunk networks. Packet switching != routing over the public internet.
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there is nothing new to this kind of thinking.
there is a paradigm shift going on through out the telecom voice/data industry
such a move is already being made in the "test-bed " countries like CHINA and INDIA where the telco network is newly gaining great importance in infrastructure.
already in INDIA the BhartiGroup and RELAINCE (2 main telco operators) have their backbones as IP based traffic.
it seems strange that such a move made in such "developing " contries is only being taken up in the US.
You can have QoS on a packet switched network to...
(Being able to dynamicly allocate bandwidth to users can be really handy compared to the fixed switched networks.)
And you can even have a private network.... making it just as secure as a switched network (even more secure as you can add encryption to prevent clandestine wire taps).
Add to this that a traditional switched network gets really noise after a few switches and digital networks will be able bounce your signal around the world without adding additional loss....
Jeroen
Secure messaging: http://quickmsg.vreeken.net/
... I still doubt I'll be able to make calls on my Sprint PCS phone between 9-10pm. Once 'nights' kicks in in this town the network is perpetually busy.
Won't this be a loss of Quality? Bandwidth is money is also true for telephone companies. I used some cheap numbers for inernational calls an always noticed a few lost packets. Thrifty compression algorithms will do the rest...
If they get rid of dedicated circuits then how am I going to get out of the Matrix anymore?
They will probably be switching to an isdn network over glassfiber as backbone. Most of the world did this years ago. (You will have a hard time to find an circuit switching telephone network in the Netherlands, although most actual connections are still analogue it gets digitized the moment you reach the central)
Jeroen
Secure messaging: http://quickmsg.vreeken.net/
It seems that technology moves in cycles...
"Serial is slow, let's move to parallel."
"Now parallel is slow, let's go to serial."
It all started with central, time-sharing systems, then switched to distributed computing when the technology permitted, and there now a trend torwards centralized administration again.
Batch processing was popular, then on-line processing replaced it, now many things are going back to batch processing because of the time/cost advantages it provides.
It seems that as technologies disappear, even newer technologies come along that remind everyone of the (still) very valid why they were using the older technologies in the first place.
Just wait, in 5-10 years, CRTs will be popular once again, and I suppose circuit switching will probably find a new foothold as well.
Slashdot gets worse every day... Pipedot: News for nerds, without the corporate slant
Assuming at some point in the future voice calls will be via "packets" from end to end, instead of just from the exchange to exchange, what kind/amount of bandwidth would/does reliable conversatinons require.
Anyone using this type of service already, how good is the quality on it? Also how does the phone connect to the providers server?
Looks very promising and should hopefully lead to at least a freeze in the cost of phone calls, and hopefully a steady decrease.
37 - what does it stand for really...
Will Sprint use the Evil Bit?
Well I made my first comment just to the point accross that just using a packet network to save cost's, may not be the best idea. Things have to be done right. I really don't have a problem if they develop new standards. Instead of just using voip. Whatever they want to do, we need a bunch of telco's developing a new standerd. Instead of just hacking onto tcp/ip (or whatever)Another thought: Things work more smoothly when we work on it together and let it mature.
Part of my major complaint in the 21century is the fact that modem technology has not really improved a whole hell of alot. Sure we have Cable and xDSL service if you are lucky enough to live near a place where they saw fit to actually upgrade.
When I see stuff like this, I get this warm happy feeling inside when it seems like it's actually a *good* idea to actually upgrade from our old vintage phone system to something that can do a hell of alot more useful things. Datapackets can be uniquely identified as "voice" "fax" or "data", which could in theory make a whole slew of things possible...
Though it makes me wonder, if the telcos are going for packet based voice communications, why the hell would I bother placing a long distance call through them when I can use VoIP software. Don't get me wrong, i'll all for the idea digital packet based phone service, if for nothing else but making all phones with that service high speed internet ready.
There is no sanctuary. There is no sanctuary. SHUT UP! There is no shut up. There is no shut up.
does it run linux?
Nice idea and all that but how will the consumer benefit from this ? will we get lower call charges or will the CEO just get another 5million on his paypacket ?
What happens if voice IP traffic gets mixed with, say, a few Quake deathmatch packets? What happens if a bot starts taking railgun shots at bits of your conversation with your Mother? Or if a L33T D00D pulls down the grid for an entire city with a strategically placed rocket? I want answers, damn it!
You seem to be labouring under the mistaken impression that digital == packet-switched and circuit-switched == analogue.
:-)
Circuit-switched is things like ATM and TDM (over E1s, etc): you establish a "circuit" to who you want to communicate with (an expensive operation), and then talk over that.
Packet-switched is when you cut the data up into packets, each of which can be routed independently - they have a target address in a header, and you don't need to set up a circuit to send them. On the flipside, guaranteeing bandwidth for a stream of packets from one node to another is harder.
I knew there was a use for that CompSci degree
Pretend that something especially witty is here. Thanks.
I would have to say A, thank you very much.
Somewhere out there, someone is building systems that _will_ have a significant impact on telephony. Find these guys - that will be news.
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Sprint Moves Phone Network to IP
Why, was property in the real world too expensive?
[rimshot]
Thanks, I'll be here all the week.
The theory of relativity doesn't work right in Arkansas.
You can have QoS on a packet switched network to...
If the physical/link layer supports it.
The telco-inspired technologies typically have heavy QoS support (ATM, HiperLAN2, etc), while it is more or less absent in LAN/Internet technologies (Ethernet, 802.11).
The Internet is best-effort, and the technology isn't really suited to do end-to-end guaranteed bandwidth/latency.
If J.K.R wrote Windows: Puteulanus fenestra mortalis!
You seem to be labouring under the mistaken impression that digital == packet-switched and circuit-switched == analogue.
Circuit-switched is things like ATM and TDM (over E1s, etc): you establish a "circuit" to who you want to communicate with (an expensive operation), and then talk over that.
Hmm. Doesn't ATM do "virtual circuits" over a packet switched medium? Not that different from a TCP session, except that an ATM VC can provide guaranteed bandwidth and latency.
In my book "circuit-switched" == dedicated line from end to end, doesn't matter whether the signal is analog or digital. With that definition, ATM is doing virtual circuit switching over a packet switched network.
If J.K.R wrote Windows: Puteulanus fenestra mortalis!
Part of what you are describing is called virtual circuit switching in which a 'circuit' is established over a packet switched network. In real circuit switching there is a dedicated electrical circuit between the two endpoints, which indeed can be both digital and analogue.
TDM is sort of a strange thing in that there is no real electrical circuit but you do get a dedicated time slot on the line. ATM definitly is packet switched.
Guaranteeing bandwith (QoS) is not hard at all, the routers simply need a table of active circuits.
Only packets for those circuits and in only a certain amount get through.
Jeroen
Secure messaging: http://quickmsg.vreeken.net/
I presume the insertion of "IP" in the title of this article was a mistake or assumption made by a naeive author? You don't use IP to carry telephone calls on a phone network. Ever. IP is no good for carrying voice data and there are many better protocols around which were designed for this purpose. I presume that they really mean ATM or some other voice protocol? You need a small packet, circuit based protocol to handle large numbers of voice calls efficiently. Although IP could be made to work, it would be pretty difficult and is essentially rather like trying to put a sealed bus in a sea to try and make a ferry - why not just use a boat?
Nick...
The really fun thing about this means that any router can be told to simply copy every packet in a particular conversation to law enforcement.
Add to this that a traditional switched network gets really noise after a few switches and digital networks will....
This kind of switching hasn't been done for years. Electronic phone exchanges have existed for decades, and digital phone exchanges (at least where I live) have made up the entire network for over 10 years.
The electromechanical exchanges did manage to hang on into the early 1990s in many places though. Good old Strowger. (An excellent site about the phone network in days gone by is Light Straw. If you are ever in a position to visit the London Science Museum, they have a good-sized portion of a Strowger phone exchange that you can play with - makes lovely clattering noises!)
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Although they will probably use IP to transport voice data between their switches, that does not mean that any of the data will travel over the public Internet or that the end users will use IP. All this does is change the design of the subnet used to transport voice data in between toll switches, not the interface between the toll switch and the end user.
Mea navis aericumbens anguillis abundat
British Telecom's main fibre optic backbone is a packet-switched network. It's only the "last mile" that's truly circuit switched these days. We have a fairly modern telephone system in the UK, only hampered by stupid area codes based on centres of population rather than numbers of people as in the US (so the big towns such as London, Bristol, Reading and Leicester ran out of numbers quickly and had to have their codes changed). To be fair, no-one anticipated fax machines and data connections when the coding system was decided.
When I am king, you will be first against the wall.
All very nice but what happens when one VoIP office needs to talk to another VoIP office over the packetized carrier. The analog voice data will be packetized in the first office to pass over there LAN converted to analog for the connection into the carrier who convert back to packetized data to cross this carrier, converting back to analog to interface with the second office who the re packetize to cross their LAN. With all the buffering required to do this what's the quality going to be like at the far end and will it sound like I'm calling from the moon?
I found it interesting that Telus, a Canadian telco, will use equipment from American companies Cisco Systems and Juniper Networks whereas Sprint, an American telco will use equipment from Canada's Nortel.
I have nothing particularly insightful to say right now. Talk amongst yourselves ;-)
Sprint with packet switching. So clear, you can hear a pin drop...twice.
One more crippling bombshell crushed the already beleaguered circuit-switching community when slashdot.com community didn't care that the use of circuit switches has dropped yet again. Coming on the heels of a recent Usenet survey which plainly states that circuit switches are boring, this news serves to reinforce what we've known all along. Circuit switch use is collapsing in complete disarray, as fittingly exemplified by falling dead last in the recent Cowboy Neal polls.
You don't need to be a Kreskin to predict circuit switching's future. The hand writing is on the wall: Circuit switching faces a bleak future. In fact there won't be any future at all for circuit switching because it is dying. Things are looking very bad for circuit switching. As many of us are already aware, the circuit switch continues to lose relevence. Red ink flows like a river of blood.
Fact: Nobody cares Timmy.
So when you use a dail-in account with a sprint-network, everything will be converted to packages first, then send to your provider over the internet, converted back to analog, converted to digital and then you have your connection on the internet?
Yup. All reasonably modern telcos today have digital exchanges. Telenor, the old telco monopoly in Norway, started the change in 1986 and the last analog exchange was replaced in 1997.
Modem - Analog line - Local telco exchange - digital through telco network(s) - Local telco exchange - Analog line - Modem
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Can you imagine a Beowulf cluster of these?
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The Sprint Press Release states that they are going to use ATM, not IP.
RFC1925
1. This is only going to help drive down cell phone prices, helping to make land lines obsolete once again. (This was likely to happen eventually anyway, right?) If the article is right and you can forward your conversations to any IP address (at an extra cost), the primary advantage cells have are mobility, such is the case now. Until, that is, when you think about wireless solutions and VoIP. Mmmmm...DHCP + VoIP :)
2. A brief search of the web suggests VoIP can be more secure than traditional telephony. To what extent will government fight this? Effectively having an SSH tunnel to the other caller wouldn't be appreciated by the gov't given the present modus operandi of the US.
3. VoIP is certainly a logical progression, and I don't see the big telcos going out of business soon. Where I live, there are just a few DSL providers but only one company (SBC) owns all the wires into the area. Their only real competitor is cable TV whom they are fighting tooth and nail to gain marketshare. I imagine access to wireless frequencies has very little competition (think: 802.11), but will there need to be legislation to keeping it open?
To-do List: Receive telemarketing call during a tornado warning. Check.
I have been installing VOIP, VOFR, and IP Telephony for years now for many businesses, I have lots of 99.999% uptime systems, no complaints in almost two years for quality of voice, I can't believe /.ers are amazed and puzzled by such simple things as a forty year old idea being used by a carrier. I guess /. isn't what it used to be.
Have you ever used a cell-phone on a modern cell network? It is 'packetized' Also, packet networks are slightly more secure as it is more difficult for even the cell company to bug you... They have to find and reassemble from the network all packets comming and going from your phone.
The French telephone network has been entirely packet switched since at least 1968. Oh, well, America gets there in the end...
I'm old enough to remember when discussions on Slashdot were well informed.
Enterprise-level synergies ... best-of-breed ...
[Puke]
Gee! Isn't it amazing that countries that don't have an infrastructure would be building one using current technology and a country that has a huge, solid, working one would be a little slower to convert to something new. Because the US was an "early addopter" of telephone technology, we're a little slower upgrading but we've been talking all over the country for a loooong time.
Profanity - The sign of a small mind trying to express itself.
All bandwidth is shared.
I wonder if this is related to the comercial I saw this morning with sprint now selling pcs laptop cards for wireless internet connectivity.
As x approaches total apathy I couldn't care less.
DSL shares bandwidth too, before it gets to the final switch and out to their house. Same effect, just different way of doing it.
Whoever stated that signature sizes should be limited to one hundred and twenty characters can just go ahead and kiss my
"Politics is a pendulum whose swings between anarchy and tyranny are fueled by perpetually rejuvenated illusions." -- Albert Einstein
My uncle is an old-timer, circuit-switch technician for at&t -- he keeps the things running and is the lead tech across several states. He tells me packet-switchin' ain't all that, and although at&t is "looking into" going packet-switch over circuit, for the volumes they do, it's just not ready to replace it yet. To back up that claim, he's taken me through "the node" he works at and the majority of it is housing the nortel, circuit-switch racks. Of course, no one has stated at&t is going packet-switched, but I found this story interesting based on the conversations I've had with him.
His blurb on the issue is that voice, unlike data, requires a dedicated connection, and packet-switched doesn't give ya that -- circuit-switching can/does (the packets can arrive out of sequence). Now, I'm prolly mutilating his take on this since this is me (who doesn't understand all of this) trying to regurgitate conversations in the past with him (and maybe my DIMMs have been polluted by searchnetworking.com and reading this forum too).
"All great things are simple & expressed in a single word: freedom, justice, honor, duty, mercy, hope." --Churchill
AT&T outright said that they won't be buying any more class 5 gateways - They said that 3 years ago, instead moving to packet switched networks.
Slashdot seems to think that this move is new. It's been going on for 3-4 years.
Can we put our friends and family on LAN-specific addresses? It would be nice to have:
MOM 192.168.0.10
GF 192.168.0.15
etc.
reading /. tends to make me think in this way :-b
I wonder if they will use any microsoft software. I would really hate for my telephone to blue-screen. My phone lacks the buttons.
when I try calling some one.
I am the Alpha and the Omega-3
Ah, its so nice to see major telcos moving to VoIP so they can save money, after they have worked so hard to prevent us from using VoIP inless they are the ones getting the savings.
booo.
Nowhere in this article does it say they're doing anything over IP. If I had to take a shot in the dark, I'd guess they were using something like ATM, which has all sorts of wonderful properties for real-time communication, and more closely resembles circuit switching (in the good ways) than any kind of IP connection. I've heard rumors to the effect that IPv6 allows for some of these properties, but no form of IP will ever do what ATM does, for lots of very good reasons.
I think Telus is nuts to use IP. I hope they succeed, but I still think they're nuts.
WARNING: there is a trojan on your
See Nortel UEMG9000 for info.
I used to work on this, and can say that its quite a robust system. Runs about 8000 POTS lines or 2000 xDSL, and also supports DS1 and TDM lines. Backbone is OC3 ATM with other options available. VOIP should be done now/soon but I don't believe Sprint went that route. The system has Echo Cancellation and all the other required perks to ensure good quality.
Used to.. Anyone need an embedded driver dev in RTP?
Do you have a link, by any chance?
AT&T and MCI have been doing this for years (using IP on their voice backbone) using "SoftSwitch" technology from 3com Commworks. It wasn't marketed to the general public since it gave the big boys a 'competitive advantage', saving them millions per month in tariffs.
Now that Commworks has been sold off, 3com still owns the technology and plans to market it. It has been in production over 5 years, and i'm hearing that it puts anything from Nortel or Cisco to shame. And it runs on Solaris, hehe..
>tracert 2001:630:1c0:1:201:2ff:fea9:9ae0
Tracing route to chaz.ws.ipv6.ne-worcs.ac.uk [2001:630:1c0:1:201:2ff:fea9:9ae0] over a maximum of 30 hops:
1 3 ms 2 ms 3 ms 3ffe:b80:1c5d:1:200:cff:fe3e:d15a
2 72 ms 137 ms 126 ms 3ffe:b80:3:5d89::1
3 97 ms 77 ms 66 ms tu-viagenie.ipv6.noris.de [2001:780::b]
4 157 ms 179 ms 197 ms 3ffe:b00:c18:1017::2
5 467 ms 465 ms 454 ms 3ffe:2100:1:9::c13f:5e06
6 * 529 ms 516 ms 2001:630:0:f006::2
7 463 ms 472 ms 464 ms int-ipv6-gw.ne-worcs.ac.uk [2001:630:1c0::3]
8 451 ms 456 ms 449 ms chaz.ws.ipv6.ne-worcs.ac.uk [2001:630:1c0:1:201:2ff:fea9:9ae0]
Trace complete.
Is suing Sprint for violation of its IP. ;)
Waiting for ad.doubleclick.net...
An IP phone network sounds disgusting!
I have an issue with IP based calls. Now granted, Sprint may not stop/reduce the number of packets sent when I'm not talking, or there is a pause in the conversation, but I HATE it when I can't hear the background noise -- the ambient noise that always occurs on the other end. Stuff like another person saying something. Analog? I can hear them. Digital/IP? Most times either I don't know the call is being IP packetized, or I hear absolute silence and then maybe it cuts in. It's like a friggin' speakerphone.
If Sprint goes IP (and maybe a lot of other providers already have too) I sure hope they don't do compression of the signal to the point where I hear nothing (not even ambient noise).
I still think analog is better -- audiophiles will agree.
TossableDigits.com: Temporary Phone Numb
In my office for the last few years I've had a Cisco VOIP phone - the only connections it has are power and network. It works pretty well, and that's an older phone.
Voice over IP is the way voice traffice will be handled in the future. The article talks about sending IP traffic over ATM, at least for now - it's more expensive that way but the cost of new switches is also quite high.
You might want to read more on the "Martini Draft" and MPLS to get a sense of how ATM will be replaced by IP technologies.
"There is more worth loving than we have strength to love." - Brian Jay Stanley
But that is packet based (IP like) traffic over ATM. They are just using ATM because it will take them a while to replace the ATM switches - elsewhere they say about 14 years until they have a "native" packet based network!
"There is more worth loving than we have strength to love." - Brian Jay Stanley
> Is this the beginning of the end for circuit-switched networks?
This shows a deep lack of understanding of the real nature of the internet (yeah, well, its slashdot, i know). Most core backbone IP networks are layered over circuit switched networks, thanks to high-speed ATM technology. In fact, there is some work by McKeown et. al, which i am too lazy to cite now, that shows the backbone core of the Internet is (underneath) primarily circuit-switched.
Cool... I suppose now we can slashdot the phone network!
:P
My sister have been trying that for years but still no effect
Boy, does this take me back. One of the better articles in Wired magazine's history, in my opinion, was the one on "Netheads vs. Bellheads" highlighting an internal battle at Sprint as a microcosm of a bigger battle of packet-switching vs. circuit-switching. It's long but entertaining and worth it, talking about philosophical differences and ATM and IP.
Packet-switched telephony is old hat. It hasn't had the kind of broad-based consumer support that it probably could have, but businesses have been using enterprise-scale packet-switched telephony for more than a decade. Businesses like Clarent, Sonus and Siemens have already carved out the space for current VOIP and packet-switched technologies. Some countries with developing communications infrastructures are skipping circuit-switched telephone systems entirely and moving straight to packet-switched backbones.
They tried to offer consumer VOIP over CATV a couple years ago here in the Denver area, but this was also back when Qwest was "riding the light". Consumers liked the idea of one bill, but didn't like having to depend on a single incoming cable, and a single company (AT&T) for everything. There also wasn't much savings. (It all smacked a little of the time before the Bell breakup.) Given that the local cable company has changed hands about every five years, consistency in service may have also been a concern.
Has anyone around here got/tried VOIP over cable? I'd be interested in knowing what the experience was.
Time Warner telecom made a handy bundle (and probably still does) on installing SONET rings for businesses to use for putting their phone calls on packet-switched networks -- all to cut the cost of long distance down to a fraction. As someone mentioned in another post, you can get the same 99.99 quality from packet-switched telephone systems as you get from circuits, and two stage dialing (not to mention billing metrics) is much easier to manage.
Clarent, the early leader in VOIP gateways (now under new ownership, btw), has got some great softswitch technologies (Class IV and V call managers) that do SS7, H323, and a bunch of other protocols. Having spent more than my share of time prodding 5ESS and Datakit, it's comforting to see softswitches taking more of the burden, and circuits being freed for other uses.
I like reading /. just as much as anyone, but this post wasn't terribly exciting and didn't say anything new. There's so much that really is exciting in telecom that I'm led to believe that this one must have snuck past the front line. Hopefully we won't see forthcoming stories about how "Graphite powder reportedly makes Abacus calculations faster" or "Fifty ways to soup up your slide rule".
-- ninjagin"640K ought to be enough for anybody" - Bill Gates
.. pa-ra-bo-la, pa-ra-bo-la, 2 pi R, 2 pi R, where's your latus rectum, where's your latus rectum, 2 pi R
So by then no one will use "old" phone networks like that. Everyone will have a cellphone, and all "land lines" will be just for net access. :P
FYI, ATM is about as close as you can get to circuit-switching and really is not a phenomenal leap forward (for the telcos maybe but in terms of network technology, not really). While ATM does virtualize the link to allow for packets, it still has the notion of virtual circuits/virtual paths. ATM very much follows the circuit-switched paradigm of yesteryear, just with a different flavor.
ATM was all the rage about 5-8 years ago, best of luck trying to do any cutting edge work with ATM right now.
dial 555-3175 ... Request timed out.. Ring..
555-3175 contacted, waiting for reply
Ring... Ring...
We're sorry, the customer you dialed connot be reached offline, would you like to connect or remain offline?
----
my question is if your phones crap out and you need to reinstall tcp/ip on it, how do you call tech support?
First the backbone goes to a digital packet switched network, with A/D conversion going on when the local telco tries to go outside. Then the local telco goes all digital, with the A/D going on when the copper meets the CO. Next we are going to see A/D happen right at the telephone (already happening with some systems).
The only logical progression is to pull analog out of the loop completely for the last 1/2" between the phone and the user, bypassing the soon to be obsolete analog audio output "mouth". The only technological hurdle for doing this is to figure out how to install the interface into the antiquated standard form-factor "skull" case most end users still lug around with them everywhere they go. Perhaps we should look into a new IEEE standard for that and start adopting it now.
The Internet is generally stupid
I don't see us going back to installing thousands of miles of copper in a city or installing TDM technology anywhere but to the doorstep.
What about putting up huge antenna towers and running TDM through those? Some digital mobile phones are based on time-domain multiplex technology. As far as I know, GSM is like this, carrying voice and data in burst signals. (Other digital cellphones use code-division multiple access, or CDMA.)
Will I retire or break 10K?
You can compress voice down below 20kbits and get a quality comparable with analogue phone lines.
Voice typically runs at 8000 samples per second. Compression of such a signal below about 24 kbps is typically based on a complicated linear-prediction model. Linear prediction, especially at GSM bitrates (13 kbps), has trouble with background noise.
Will I retire or break 10K?
Anyone remember Sprint's attempt at merged services, called ION? They installed a router in your house and all of your communication needs ran out of that box. The router connected to Sprint's network and ran voice and data over ATM. It was a very neat idea and might have worked if there were more early adopters (and if they could have resolved all of the installation issues... I worked on part of the software that brought together the connection allocation, tracking and billing systems, and it was extremely complex)
I didn't subscribe to the service because the cost was prohibitive for personal use, but it seemed pretty cost effective for business use (4 phone lines and a T1 downstream, 256kbit upstream for $200 a month [I think] and that included several hundred minutes of free long distance per month).
I don't believe the subscribers had to change their phones to allow that to work, they just had to have Sprint's router in their house that all of their phones tied in to.
Yes - it is going on elsewhere - try right in the good old US. I do some work for a rural phone company (30,000 lines) that has an entirely packet switched network. They did not make any big announcements, and I bet that 99.99% of their customers don't know or care. Because the telco can control the QoS, the quality is at least equal to the traditional infrastructure.
Many of the rural telcos adopt these types of technology more quickly than the baby bells. How? You and I are paying for it every time we pay our phone bill - Universal Service Fees have subsidized a tremendous improvement to rural telephone service.
And it should be.. why should they be forced to use ancient and expensive technologies on the back end?
This isn't even super high tech or anything.. it's just that phone companies have a level of service to provide, and making big changes takes big planning.
WE waste way too much bandwidth on voice.
Circuit switching will probably return under the guise of "guaranteed quality of service" over the unreliable packet switched network. In fact, ATM does virtual circuit switching already.
cpeterso
Er. It depends what you mean by circuit-switched. When you want to talk to someone via ATM, you need to establish a virtual circuit to them, a process that involves each ATM switch between you and the other VC endpoint. This sets up the path the ATM packets in that VC will take through the network (and ATM packets are *small* - 53 bytes).
Compare this with IP, etc - the routers don't (or at least shouldn't have to) care about anything beyond the destination header in the packet, something that shouldn't be modified en-route. TCP doesn't require the intervening routers to know about it.
Pretend that something especially witty is here. Thanks.
Thats a cool site about the phone system in days gone by, got any good sites about the curent phone system?
If I can send an email across town and across the world for the same price. A local phone call. Why is it a local call and a long distance call cost different?
:)
Voice over ip. Charge by bandwidth usage. A call across town should cost the same as a call across the world.
Anybody?
Bryan
Amazed and puzzled? I think not.
All I'm trying to point out is that they will no doubt discover some purpose in the future where switched-circuit systems are better suited than packet switching.
It's quite possible the more important systems will go back to being circuit switched because of the better reliablity... With no other devices sharing the line, there's no chance of resource exhaustion. Just ask Bank of America how well their VPN worked when SQL Slammer hit. I'm not sure that's the main advantage of circut switching, but I have no doubt technology will turn around, and make circuit switching in-vogue again.
Thanks, but I'll stick with my 100% uptime phone system for now. Not that VoIP is terribly useful for residential situations right now.
Slashdot gets worse every day... Pipedot: News for nerds, without the corporate slant
Your phone system is only 99.999% up. This equates to about 10 minutes unscheduled downtime per year, per line. Of course this is an agragate number for all phones on the network.
"Well, good luck finding a judge that doesn't run a bestiality site."
VOIP does not have require the same bandwidth for identical quality. The above statement is FLAT OUT WRONG. VAD (Voice Activity Detection) alone can dramatically drop bandwidth requirements for even a G.711 (no compression) codec. (Most of a phone call is silence, as speakers pause between words and phrases. If no data is transmitted after a tiny "silence start" packet, then bandwidth is immediatly saved).
Acceptable PSQM (PSQM, perceived voice quality, ITU standard testing) scores are attainable using 30 millisecond codecs, and even multiple voice frames per IP/UDP/RTP (RTP = Real Time Protocol).
So when you take say, 30 milliseconds of G.711 (uncompressed) data, tack 42 bytes of Ethernet/IP/UDP/RTP header, the header starts to diminish when compared to 40 bytes of uncompressed voice data per 10 millisecond period (120 bytes per 30 ms packet).
Still not terribly efficient, but PSQM scores with these codec configurations have IDENTICAL scores in well designed systems/networks to conventional PSTN telephony. Throw in even the simple VAD/DTX and bandwith is saved with a zero-compression codec. Add in some of the common "real" codecs that do compression, (G.729, G.726, G.723) and significant bandwidth is saved.
There are single chips that will do the conversion from traditional telephone networks to packet networks (either ATM or VOIP) and do hundreds of calls per chip. These devices are being used to build the gateways being used by the telco's in every majior country to build the next networks. In countries like China, they are building the infastructure from the start using VOIP networks.
Slashdot is not what it used to be...
One point to make here .
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As someone that worked in the Telco industry there
are -->> ** NO ** -- 100% uptime systems
At some point, the system will error, busy out,
or a fiber seeking backhoe will feed itself
The last major california earthquake showed them
that they needed a system with dynamic routing
capability on the fly
When the World Trade Center fell phone service was
in big trouble in that area for some time
This has been played out time and time again
not only nationwide, but worldwide
VoIp can change some of it, but not all of it
Nothing man can make is 100%
The US phone system is geared around its heaviest
call voume day, mother's day, That is their loose
benchmark
The reason he quotes 99.999% is that is the five 9's
reliability quotient set by the FCC
VoIp Dial offload is providing 5 cents a minute any
time night or day , 365 days a year , and you do not
even know you are using it most of the time
It is transparent to the end user if done correctly
Companies like Sonus and Genuity made millions off
their VoIp solutions, and so did many others
I worked at a now defunct Cisco Systems VoIp lab in
Herndon Virginia that used MGC , and it was steamrolled
by SIP internally , and other solutions externally
When the other solutions beat us out, Cisco nearly
closed the facility they laid off so many people
Over 50% of the office I worked at was let go, and a virginia law
came into effect for letting so large a number go
I learned alot there, and one thing for sure is that
there are no 100% uptimes
Only multiple redundancy can give you 100% uptime, and then
you are just building a 2nd parallel network
Peace,
Ex-MislTech
google "32 trillion offshore needs IRS attention"
Er. It depends what you mean by circuit-switched. When you want to talk to someone via ATM, you need to establish a virtual circuit to them, a process that involves each ATM switch between you and the other VC endpoint. This sets up the path the ATM packets in that VC will take through the network (and ATM packets are *small* - 53 bytes).
:-)
True. I guess we're just arguing semantics.
Anyway, in my book a virtual circuit running over a packet switched network is an emulated circuit over a packet network.
ATM cells are small, and ATM is specifically designed from the ground up to facilitate virtual circuits. No argument there. But it is still a packet switched network, imho.
Compare this with IP, etc - the routers don't (or at least shouldn't have to) care about anything beyond the destination header in the packet, something that shouldn't be modified en-route. TCP doesn't require the intervening routers to know about it.
IP is best-effort, TCP is a session protocol on top of IP. None of them have any comprehensive support for the kind of QoS you need for voice connections.
However, you can do pretty much the same thing for IP traffic by using MPLS, 802.1p and 802.1Q.
If J.K.R wrote Windows: Puteulanus fenestra mortalis!