Server Fault is a question and answer site for system and network administrators. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

We are in a semi-rural area, so our internet connection options are pretty limited. We currently pay about $500/month for a dedicated T1 line at 1.5/1.5 Mbps from the local ISP. In comparison, Comcast is offering a 16/2 Mbps "business" internet connection for $90/month.

Other than raw speed and their SLAs, what metrics should I be comparing the two services on? I've heard people say that cable is not as secure as a dedicated T1 in the past, but never seen any evidence to back that up. Is there any reason to stick with a slower line at over 5x the price?

share|improve this question
up vote 9 down vote accepted

We have both where I work. The T1 is used for our outward facing services. FTP, WWW, VPN, etc. The Comcast connection is used for all the out going requests. So people in the office web browsing etc. In the case the Comcast connection goes down this traffic falls back to the T1 as low priority traffic.

So both links are monitored and the cable connection does go down more often but this is normally in the middle of the night for a few minutes max. I'm assuming this is probably a maintenance window of some sort that Comcast uses to update things.

Bandwidth wise the main difference is the T1 is guaranteed where the Cable connection may be slow during peak times. In reality I haven't seen our Comcast connection slow down much and consistently see 16Mbit download speeds. The other difference you'll likely find is in the case of a disruption in service. The T1 provider will have more pressure on them to resolve the situation quickly due to the SLA. We had an ice storm here in the north east last year. The office was without power for 1 week but we were running on generators. The T1 surprisingly never went down. But it took about 3 days for Comcast to get their networks back up.

Security wise neither are secure and if you need security you should be using VPN's or encryption period. Anyone can sit on a telephone pole and clip a couple of wires to your circuit and capture all the data flowing on it.

share|improve this answer
I should add that we were also paying $500 a month for our T1 until recently. Our old contract was up and we renegotiated a lower price that was in line with the current market price for our area. Cable will still be cheaper than a T1 but I would get a couple of quotes to get current pricing before making any decisions. – 3dinfluence Oct 14 '09 at 16:54
I have Cablevision's business cable (Optimum Business). It's acceptably fast, though the upload is routinely below 50% of advertised. Biggest issue - it really IS repackaged consumer service. There's no SLA, problems don't get fixed any faster than residential customers. About the only difference is a different support line with shorter wait times. – Jason Antman Oct 14 '09 at 17:05
Also - IMPORTANT - the helpdesk guys for most of the business cable don't know any more than the ones who help residential customers. If you're having problems with your cable modem and start telling them what the modem is reporting for SNR, transmit power, microreflections, etc. they'll get confused to no end. – Jason Antman Oct 14 '09 at 17:06
My experience with Comcast Business support has been very good. Almost no hold times and very knowledgeable helpdesk staff. So I guess your milage may vary. – 3dinfluence Oct 14 '09 at 17:30

More consistent upstream bandwidth (the number reported for the T1 is actual available rather than theoretical max), dedicated line (less stress from "sharing" your connection with others going to the same local office), better stability, better service level agreement/support.

share|improve this answer

The main things are symmetric bandwidth, and less bog down at peak hours.

share|improve this answer
What is the benefit of symmetric bandwidth when it is less (in both directions) as the asymmetric bandwidth of cable? – Sysadminicus Oct 14 '09 at 16:24
cable is not symmetric, its 16 down and 2 up, and that is also dependent on other users on you segment of cable, while t1 is going to be 1.5 both ways near all the time – Jimsmithkka Oct 15 '09 at 3:35

T1 is dedicated bandwidth. It generally doesn't slow down.

@3dinfluence. We also lost power for a few days. Our telco provider had a generator up and running before the battery backup on the switch ran down.

Comcast is shared. You will slow down at peak times. I've seen upload speeds as low as 128k. This didn't last long, but it happened.

Shared means something else too. Your traffic CAN be seen by everyone on your branch. Branches are generally limited to your immediate neighbourhood. This would involve putting the cable modem in promiscuous mode, which I believe there are safeguards against, but the data is out there if you can get to it. You don't even need to leave your house to do it.

Take a look at Uverse or fios if you can get it. Not shared. Nothing on the same wire as everyone else.

share|improve this answer

Depending on your SLA and requirements, I've been under the impression that the T1(E1)/T3(E3) lines are yours to do with what you want, so you can take the CSU/DSU and split into your own branches for phone service and run data side-by-side with your voice service. I wouldn't think that you're interested from the OP, but it might be relevant for people considering a new service setup or working on their home scenarios. My wife's mentor has a T1 to his house since it was cheaper than other options considering his location.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.