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Cable vs. DSL, Explained
Alan Shutko writes "Simson Garfinkel has a great article on Salon which explains the relative merits and disadvantages of cable modems and DSL. This should quiet the cable/DSL wars seen occasionally. " Very good overview of the difference between cable and DSL, cutting through the hype of the various companies.
Presumably you meant "Bell Atlantic DSL"; Garfinkel lives in Massachusetts, where Bell Atlantic is the local phone company. One reader of his wrote in from the Bay Area, but mainly spoke of bandwidth problems with cable modems out here (although, from what I can see, the biggest bandwidth problem with cable modems out here is that they have no bandwidth whatsoever to most of the Bay Area - TCI/@Home are only offering it in some areas so far).
So far, Pac Bell's service seems to have worked well for me; they're not my ISP (because, when I asked them about DSL, they gave me some line about being too far from the central office and about them lacking the facilities to provide it, and said it'd be available some time next year; when I called Flashcom, they somehow managed to get Pac Bell to get me a DSL pipe, which Pacific Bell Internet was unable to do), so I can't speak for that part of their service, but the pipe seems to stay up and to give me a pipe that's varied between 200Kbits/s and 1.5Mbits/s, with, I think, typically something between 300Kbits/s and 600Kbits/s, from their "384Kbits/s to 1.5Mbits/s in, 128Kbits/s out" service.
But, yes, Your Mileage May Vary depending on who your ISP is and who your cable company/DSL service provider (local exchange carrier, whatever) is. Garfinkel did mention that, in his article, saying, for example, about security:
on the last page (and saying similar things about DSL providers), and saying, although perhaps less directly, the same thing about speed on the previous page:I'm not sure if anyone else noticed this -- but he seemed to only quote the experiences he has had with a limited range of companies. While he admits this it still seems like he's caught up on the experiences he's had with only a few companies. Currently, I run a small network off of a 1.5/384 DSL. I pay $60/month and that includes a block of IP's (8,6 usable). The premiere cable service around here is @Home which seems very lacking. I've had people tell me that during peak hours they're bandwidth cuts down to only twice that of a dialup modem, and they pay twice as much as a standard dialup account (~$40-$50). I don't use PBi (Pacific Bell Internet) because they're government regulated and also extremely lacking in the technical department, but I do use their lines. The routing is done through a Southern CA company called Orconet. I have never had any downtime while using Orconet, ever. My latency times are typically 15ms. I have no microfilters on my phone, and I don't ever hear any static on my lines. I'm not saying DSL is better than cable -- but this article seemed slightly lobsided because this guy got stuck with a poor DSL carrier. If anybody is still debating whether to go with cable or DSL -- don't listen to much this article has to say. Most of it is so isolated to the region that unless you are in Boston it's not much good. $0.02 deposited.
-= Making the world a better place =-
Dacels Jewelers can't be trusted.
I agree with the thrust of this post, but I don't see why "price" and "quality of service" are relegated to the realm of the mundane.
These might not be as technically challenging, but there certainly are a lot of logistics that go into making these things attractive.
With price, there are a lot of tradeoffs which obviously have to take place. How quickly will the company recoup its investment? Will they charge tending toward metered or unmetered? (Most things are somewhere in the middle, viewed broadly) Will they charge for service and separately for needed hardware, or lump them all into a monthly cost? Etc -- lots of variables, and no single package of them will satisfy everyone.
And with quality of service, same thing. Do you hire lots of tech-support people and charge a commensurate amount extra on the bill? Or charge less, and offer less service? (Etc, etc.)
As mochaone points out, "The companies that build relationships with their customers will retain them." Look at the (even dysfunctional) relationship approach that AOL has with people
Cheers,
timothy
jrnl: http://tinyurl.com/c2l8yr / foes: http://tinyurl.com/ckjno5
Hmm. So where exactly does Covad, say - who provide service to Flashcom, as per this item on Flashcom's site, which says
fit into this picture?
The impression I had was that my phone signal was split into voice and DSL portions at the CO, with the DSL portion going into Pac Bell's ATM network, running over that network to Flashcom, as per the comment
at the end of this Pac Bell page. Flashcom then routes my packets to sites elsewhere on the Internet and routes packets from those sites to me.
Pac Bell has provided Internet service (which I view as "routing packets to and from sites on the Internet, and possibly providing other services such as DNS lookup, mail service, netnews service, and the like"), and some amount of support for DSL for other ISPs, for several months now. They also , as far as I know, allow CLECs such as Covad into their COs as well.
Just for informational purposes im quickly going to run thru the major methods of getting a DSL connection. I imagine the same applies for cable.
:)
:P)
When you power up your DSL modem the first thing that happens after the power on test is it attempts to sync with a line card in the captive office. Depending on what kind of system you are on this could be at anywhere from 100kbps to 9Mbps and down. Typically up tends to be significantly less then down (usually in the 320kbps to 1.5Mbit range) but it does not have to be.
There are several encapsulation methods used to get packets over the DSL wire all of them revolving around ATM.
The end to end connection typically looks something like this:
PC --Ethernet-> Modem --DSL-> LineCard --ATM-> ATM Switch/Router --Whatever-> Internet
From there it your data can bounce around the net
being re-encapsulated until it eventually becomes ethernet again.
Typical encapsulation methods over DSL are:
RFC 1483 Ethernet over ATM (most common)
RFC 1577 Classical IP over ATM
RFC 2364 PPP over ATM
1483 encapsulation involves setting up a bridge group on your router. A bridge group is essentially a software hub that sucks in packets from multiple connections and forwards them along to wherever they need to go.
If you have a setup like this, when you look in your arp cache you should only ever see the (fictional) MAC address of your bridge group.
(and your modems MAC assuming its not a dumb bridge either)
1577 isnt used much in the real world as it requires more effort to setup and maintain.
2364 is becoming more prevalant, especially a nasty variant called PPP over Ethernet which is like a combo of PPP over ATM and 1483 bridging.
Just so you can see all the work thats going on
here are the quick protocol stacks for the data encapsulation methods before the data ever hits the phone wire. (pretty complicated
1483: TCP/IP->802.3->RFC 1483->AAL5/ATM->ADSL
1577: TCP/IP->AAL5/ATM->ADSL
2364: TCP/IP->PPP->RFC 2364->AAL5/ATM->ADSL
PPP over Ethernet: TCP/IP->PPPOE->802.3->RFC 1483->AAL5/ATM->ADSL
Anyhow, hope this was useful.
Oh yes, one last note about speeds. While most DSL available today sits in the 1Mbit range or so
within a year or so high speed DSL will start to roll out offering equal or better bandwidth compared to cable (i.e up to full 10Mbit down and 1.5Mbit+ up)
Enjoy the competition, its good for you the end user.
-N
Correct (although in my case, they're using the ILEC, Pac Bell, rather than any CLEC).
As far as I know, they're not just reselling Covad's services, though; I don't think Covad is doing the routing for them, I have the impression Covad just moves data from some ILEC's CO to Flashcom's routers.
They're referring, as far as I know, to the pipe they provide between a subscriber and their ATM net, and to the ATM services they're providing to ISPs including but not limited to Pacific Bell Internet. See, for example, this diagram on Pac Bell's site, which shows the line to the CO, the DSLAM in the CO, and the ATM network - they run a PVC over that network to the ISP, or to a corporate LAN if the DSL circuit is being used for telecommuting to work rather than connecting to an ISP.
For CLECs, the picture is probably the same, except that the DSLAM belongs to the CLEC and is in the cage they rent from the ILEC, and, presumably, so does the ATM network - this page on Rhythms' Web site seems to imply that they have their own ATM network, independent of any ILEC's network.
Yes, there's a splitter at my demarcation point, which sends stuff up to 4KHz, presumably, along one wire, into which my Plain Old Telephones plug, and stuff above 4KHz along another wire, into which my DSL box plugs. There's also a device at the CO that does the same; that's presumably the "Mux" in the aforementioned diagram on Pac Bell's Web site.
Pac Bell puts a USD 39.95 item on my phone bill for DSL, so it's presumably their DSLAM. (I presume Flashcom will send me a USD 10.00 bill one of these days; they may offer "first month free", but it's been more than a month - I should call them to find out what the story is, as I don't want to have my Internet service cut off for non-payment of a bill that I never got in the first place....)
The author of the artice is right when he says that the better technology won't win. It also really depends where you live - where I am you can get 1Mbps ADSL and cable modems for $40/month.
What I am more concerned about is security. With dial-up connections at least you were a moving target - the IP changed and you weren't connected for a long period of time.
Now you have a static IP or a dynamic (DHCP) one that stays the same for long periods of time. All of a sudden you have thousands of computers sitting there wide open and vulnerable to attack.
Watch for it - as more people get high-speed access, this will become a much bigger issue. Windows and even the default installs on most Linux distros are not ready to be connected full-time to the internet.
Do you even know anything about perl? -- AC Replying to Tom Christiansen post.
Whether or not you can set up servers on a cable modem connection depends on your particular cable company's policies more than anything else. I know that Time Warner in the Central NY region (I *think*) has "servers" forbidden (but not ever DEFINED) in their user agreement. Also, to the best of my knowledge, they block inbound port 25. A friend of mine has had lots of problems trying to get them to open this port, even on a case-by-case basis. In a lot of cases, they just don't care about the customers; as long as they get their money, they are happy.
Mind you, this is not always the case. The San Jose Road Runner service from Time Warner (sorry if I am wrong about the area, I last heard about this a while ago) will open port 25 on a case-by-case basis after determining that the user doesn't have an open relay. This is a sensible procedure to prevent problems with spamming abuse, and should be a stand that more providers take.
Basically, make sure you check out policies before you do something like running any type of server; you might get screwed out of your connection and payment if they decide to shut you down.
---
Tim Wilde
Gimme 42 daemons!
I have a graph up online that'll show you what I mean. If you have any questions, e-mail me and I can give you the raw data, and some other statistics. I live up in Minnesota.. and some of my friends have also expressed dissapointment in the QoS that mediaone offers up here. I'm paying $40/mo to get substandard service during prime time - my plain old analog modem (USR 56k) to a conventional ISP is actually better after about 18:00.
I've been wanting to put together a report for the Public Utilities Commissioner (PUC) for awhile, but after contacting their office they didn't even seem to understand what I was complaining about. :( I'm out of options up here for high speed access - xDSL is available in my area (US West - keep up the good work - nothing but rave reviews) but I'm too far away to get it.
Mediaone - are you listening? How about giving us some guaranteed QoS, or giving us more on-the-wire bandwidth?
--
Recently, USWEST decided to change all it's DSL customer accounts to a new PPP-DSL based connection. This means you would have to enter a username and password in your router (aka dsl-modem). There are certain disadvantages to this new services.
.. and all the fun).
:)
When your router is in PPP-DSL mode, the DHCP server assigns an IP directly to the router. From there you have to use NAT to pierce open ports for your own NIC. People most effected by this would be gamers and those who wish to use advanced forms of internet communcation (voice/video chat, file sharing and so on).
USWEST ISP web site claims that they are giving a full internet service. But this is not so. I have been able to open ports 22, 80 and 21 for my various serices. But, everytime they change your ip. You have to telnet into your router and change the NAT tables. This gets worse if you reboot your router (since the nat is deleted off). After 2 weeks of this, I changed over to startnet, here in Tucson, which didnt put restrictions such as this (but did firewall off lower ports).
So, if your getting DSL through USWEST, dont pick them as your ISP. Check the other ISP's in your area that offer DSL with USWEST as their backbone. And ask them if they are providing PPP-DSL or Bridged mode DSL. (in which case the IP is given directly to your NIC
Most users who get DSL are powerusers and demand more from their DSL service. I was alarmed by these restrictions that USWEST was putting for DSL users. Also it went to the point that I had to use a normal modem to play quake
--
It *appears* it depends upon the service provider. Some of the service providers apparently actively LOOK for people running web/other Internet servers, while others are more indifferent. My service provider said it was against the rules, but upon asking, they told me they don't actively look, but they will investigate any curious or excessive activity.
My web server has been on line for about a year now, without any complaints from the cable company, other than the time some (*censored*) cracked my system and set up a cracking shop, using my machine as a base to crack others. Got a nasty note from the cable company which I couldn't figured out until I realized the odd things happening on my Linux box were really odd things, not just ignorance on my part!
I do wish to point out my web server is STRICTLY for experimentation and occasionally getting stuff to friends. I do think using Cable Internet Access to do commercial or high-volume stuff is really tacky. We get high bandwidth at a low cost because it is assumed we will be rarely using most of the bandwidth.
I'm with the @Home service, but a friend who is waiting for Cable Internet Access who would also be getting @Home through a different cable company, sounds like he would be getting a totally different set of terms of service than I have.
Best I can say is anyone who says "This is how it is" is probably wrong SOMEWHERE. The rules are different everywhere. The rules are still being written...
Here, they recently put a cap on the "upstream" link (128kbps supposedly), which I am fine with...means I don't have to worry quite so much in case someone finds something interesting on my server...
Nick.
If the history of technology is any guide, however, it's unlikely that the battle between cable modems and DSL will be won on technical merits...Ultimately, this battle will be won and lost on mundane issues like price and quality of service.
Truer words have never been written.
Broadband is beginning to take off and speaking as someone who makes his living from using the resources on the internet, it's about time!
For most rational people the value of downloading Netscape in 5 or 10 minutes will be secondary to the relationship your broadband carrier establishes with you as a customer. How do they respond to problems? How flexible are they with with regard to how you use your broadband? Are they knowledgable about the product?
Most of these questions will be answered based on where you live and what your previous relationships are with these broadband carriers. Have you been satisfied with your current cable service? Is your telcomm responsive to your phone line problems.
I have had serious problems with my cable company (Cablevision). From their unresponsiveness to someone illegally billing their services to my account (had to get my my congressman on them) to their inability to offer a la carte programming (in process of going to satellite programming). As a result, I decided to go with DSL. I couldn't be happier with the service. I am paying $10 a month more than comparable cable service and haven't had one problem. I've found my provider (Bell Atlantic) to be very helpful and responsive.
This obviously isn't rocket science. The companies that build relationships with their customers will retain them. Even in the face of a supposedly superior product. While the article was topical and timely, I think the penultimate paragraph could have been fleshed out a bit to emphasize this more clearly.
Hates people who have stupid little sigs
All a cracker needs to do is to keep checking these IP addresses. As soon as it gets a response from one of them, you're toast.
99 little bugs in the code, 99 bugs in the code,
fix one bug, compile it again...
I'm a leaf on the wind. Watch how I soar.
I still think Scott Adams had it right in one of his Dilbert books:
Telephone companies and DSL will beat out Cable companies and cable modems for one simple reason: All of the people that were too incompenent for even the local telco work at the cable company.
(I will post the exact quote and book when I get home).
The relative merits of DSL vs. cable modem really all rests on whether or not the network built to hold those technologies can provide the type of service. He mentions that his DSL service goes through San Jose and Chicago and New York before getting back to Boston. That's just a crappy network for that person. It hurts performance and if the lines between any of those routers get cut or saturated, you're screwed. The same can be true of cable modem service. Luckily, most cable companies operate their systems locally, so your network infrastructure is going to be local. DSL, especially in the case of national providers, may not have their infrastructure local.
I had DSL in Austin through Texas.Net this summer. Texas.Net is a regional Texas provider with massive amounts of money invested in their network, their machines, and their connections. They're ahead of their bandwidth curve, which means they have the bandwidth to support the maximum throughput possible. Thus, with DSL in Austin, local sites were pulling in at a 100K (that's kilobytes, not bits) per second, and up near the theoretical limit (150K/sec) for sites local to Texas.Net's network. BTW, if you're in Texas and want to check out this service, residential DSL service (low-speed: 1.5Mbps) is $19.95/mo plus the Bell fees. Contrary to this, my friend at MIT, who was on a shared MediaOne cable line split among an entire housing unit, never got above 60K downloading things from MIT. Routing and infrastructure take their tolls.
The key to finding the best technology is research. Concentric was probably not the best choice for DSL for a Boston-area business. You've got to ask about the network, check what their routing is like, and find out about competitors. The best place to do this is on the newsgroups for the area. While the signal-to-noise ratio is pretty crappy, you can piece together a pretty accurate description of what is good by asking the question and then sifting through the ashes.
Personally, I think DSL is better as it is guaranteed bandwidth (provided the external 'Net connections can support it), but maybe not in your area. If you find many, many stories in your area like this article, you'll be ready to make an informed decision. But don't make it based just on thisarticle.
I work for an DSL provider in Wisconsin. I see these arguments all the time. I rarely try to argue anymore.
The reason for this is because when you see a cable vs DSL argument on the irc, in newsgroups, or even in person, the people arguing are almost always arguing about the cable modem service in THEIR AREA vs DSL service in THEIR AREA. It's never an argument about the technology, always about the providers. They always talk about bandwidth on adsl or sdsl being less, but this is probably a function of the provider throttling it down. Everyone talks about security on cable, but this is all relative as adsl or sdsl can be just as lax if not implemented properly. It's almost an apples and oranges argument.
This Salon article is no different. He is comparing PacBell dsl (which sucks) to MediaOne's cable service. This is not representative of the technologies involved and frankly makes me a little upset.
Hopefully someone (maybe me) can find a good link to post that compares technologies, not services.
Or maybe someone who really is involved with cable technology can write a article here on cable technology, and I or someone else would be happy to reply with a similar paper on DSL technologies.
-=Ex-manager of Wrestlers=-
I hate it when someone talks about choice creating customer confusion. Why does everyone say that? Show me one example where choice brings customer confusion? Is the customer confused when they have 4 dozen different types of cereal to choose from? Are they confused when they have a choice of 40 resteraunts to eat at?
Choice is *always* good. Choice creates innovation. It creates cheaper prices. It creates diversity in product. Customers are greatly benefitted by choice.
Customers won't be "confused" because each solution is good enough. The are benefits to using either one. So they'll be hyped both and then buy the one that looks the best to them. No problems...
-Brent--
The description why cable modems are cool (page 2) applies equally well to DSL. In fact, take the first few paragraphs, replace cable with DSL and you have a perfectly good and valid piece of writing.
To say that a DSL line is shared with the phone service is a lame excuse. The phone line bandwidth is so tiny compared to the total frequency range of the line DSL uses, that it's not even an issue, certainly nothing even close to the amount of sharing going on on cable lines.
In the same paragraph saying that cable is the king of bandwidth and that the writer gets 7 mb/s is the statement that the modem is limited to 600 kb/s. So which is it?
And then the dismissal of the issue of line sharing (page 3). If you get 600kb/s on a cable modem, and that's enough to satisy you, then DSL will do fine as well. I routinely get 600kb/s on DSL and I'm near the bottom of the serviceability scale for DSL.
Then you have the upload speeds. How can standard cable service even compete with the ul caps?
And prices for DSL are coming down fast these days, at least over here (Calgary, Canada). You can get a 768kb/s line for some $50/month (Canadian!, that's like 5 cents US), which almost matches cable service prices.
I will admit, that from reading warious posts around /. and other forums, DSL service (as in people service) sucks; this gives a lot of advantage to cable service. But the article is not a well balanced article on cable vs DSL; rather it's cable vs 'something I've never really tried just heard about and I hate it and I think cable is oh so cool' article.
So lets keep things in perspective; this article does cut through some of the hype about cable, but merely mentions DSL in passing as some other internet technology.
Ugh, it's too early for this...
"Hot lesbian witches! It's fucking genius!"
I just got Mediaone Roadrunner installed in a boston suburb, and the performance/reliability has been spectacular so far. My only complaint is the following conversation I had with a salesperson:
Him: Hello, sir. Will you be connecting mediaone from a windows machine
or a mac?
Me: Actually, I was planning on setting up a Linux server and using IP
masquerading.
Him: (pause). Umm, sir...we don't support anything except Windows and
Macintosh.
Me: I know. I'm going to set it up myself.
Him: Would you please hold?
Me: sure.
Him (4 minutes later): Sir, we only support Macintosh, Windows 95, 98, and
NT 4-point-O.
Me: I understand that. I won't be needing support. I'll do the software
installation myself. I'll just need you to wire it up to the modem.
Him: Our technician needs to install the software on a computer while he's
there, though.
Me: Why?
Him: Because that's mediaone policy.
Me: Why?
Him: Sir, please hold again.
Me: ok.
Him (3 minutes this time): Sir, we need to send a technician out there to
wire the system, and provision your computer.
Me: What do you mean "provision the computer"?
Him: The technician needs to do that.
Me: you just told me that...what does it mean?
Him: I don't know. I'm not a technician.
Me (with HEAVY sarcasm): Really? You don't say? Ok...answer me this
question: Why does a technician need to come out, and do an installation
that I'm going to wipe out as soon as he leaves?
Him: because he needs to get the emac address.
Me: What's that?
Him: The address of your computer.
Me: Then it's a hardware thing. You can get it in Linux.
Him: Our technicians don't support Linux.
Me: I know that. I'm going to do the networking.
Him:Sir, the installation, with the fiber optics, is alot more involved
than you think.
Me (giving up): Fine. The machine will be windows 98.
Him: How much RAM do you have?
Me: 64 megs.
Him: Ok, and what's the processor speed?
Me (thinking i'll just put windows on the machine that will eventually be
the Linux server): 90
Him (another pause): uhhh...excuse me? It needs to be a pentium system.
Me: I know that. It's a pentium 90.
Him: We need at least 166 Mhz.
Me: No you don't. I read the system requirements, and it says it
requires a pentium, and a 166 is recommended.
Him: Sir, we can't send anyone out if you have less than a 166.
Me: Fine. It will be an AMD K6-2 400.
Him: It needs to be a pentium, sir.
Me: Don't worry about it, it's the same thing.
Him: Is it a pentium-class processor, sir?
Me: yes
Him: and do you have an ethernet card, sir?
Me: seeing as i am networking the systems myself once the technician
leaves, yes I have the cards.
Him: thank you very much sir. We'll have someone there to do the survey
on Wednesday.
When the guy came to install it, I started the same conversation with him. His response was basically "Do whatever you want, once I'm gone." I said "ok", and got my linux box going. If there are people out there who need help with Roadrunner for Linux, I'd recommend http://www.vortech.net/rrlinux.
Juiced? Or Not?
Although this was an interesting article, it was replete with factual errors:
DSL service is inherently more secure than using a cable modem because DSL provides a dedicated connection over your existing telephone line. A cable modem is more susceptible to hackers since it operates on a shared system, much like an old-fashioned party line
He used this in a context which was somewhat ambiguous. This was presented as an example of "noisy ammunition for their PR battle", but he never explicity stated whether he felt this was true or not. I would argue that the security problems one is likely to face from one's neighbors pale in comparison to those one faces from the world at large. Either way leaving one's computer connected to the Internet without a firewall is begging for trouble.
I can download Netscape Communicator 4.5-- which resides on a server in San Jose -- in less than 4 minutes.
I wonder if he checked the IP address he was downloading from... If Netscape's "tdns" system was working properly, the IP he got was for the East Coast Netscape colocation facility in Pennsauken, N.J. rather than Mountain View.
The company is fundamentally a West Coast ISP with delusions of grandeur. Specifically, Concentric doesn't actually have any employees in Boston. Instead, it contracts with a company called Covad to do all the grunt work.
I'm not certain, but I believe that Concentric uses Covad "to do all the grunt work" even on the West Coast.
The sleek "RISC" microprocessors from companies like Sun Microsystems and MIPS lost out to Intel's technologically inferior Pentium chips. Ultimately, this battle will be won and lost on mundane issues like price and quality of service.
I guess he missed the whole evolution of Merced from HP's PA-RISC chip.
Despite these problems, it was definately a thought-provoking article. I'm looking forward to the discussion here on Slashdot-- I bet that it provides better information than the original article!