How to Test Your T1? 488
lawpoop asks: "We have a T1 line for our building with a local ISP. Right now, we're looking for competitive bids from different companies. The local guy is offering a good price, but the larger guys are saying he may be overselling the T1 service through a DS-3. He swears he's not. So, how do I tell? The sales guys say 'There's bandwidth meters on the web,' but they fail to mention exactly how I can tell if I have a true T1. I've tried a half-dozen bandwith meters on various websites, and the results are highly variable. We've gotten 300-900 Kbps. Each site has disclaimers as to internet traffic, time of day, etc. Furthermore, we split the T1 out over a hub with two other tenants in the building. I'm coming through from behind that hub. How can I tell for certain that I'm getting a full T1? A service tech with a line tester? Any dead-on bandwith meters? What would an oversold T1 read out to be as compared to a true T1? If the larger guys are trying to scare me to their service with stories of oversold T1s, I need to know that they aren't doing it also!"
Packet Sniffer? (Score:1, Insightful)
Getting a T1 or getting a "T1"? (Score:5, Insightful)
If you're talking about getting ISP service with "T1" equivalent bandwidth, that's a different story. You wouldn't be able to tell if the guy has "oversubscribed" you unless you find other buyers of the sevice and generate enough traffic to load down the DS-3.
To prevent getting burned, make sure your SLA clearly states the bandwidth you are expecting, and the means by which that is measured.
Over selling not inherently evil... (Score:4, Insightful)
Seems to work quite well to me, but maybe I'm biased. Try an get a conference with the techs (see if you can talk to their network monitoring team) and see if they employ a similar practice.
Re:A Full T1 is ... (Score:3, Insightful)
Re:dslreports.com (Score:5, Insightful)
Re:dslreports.com (Score:3, Insightful)
If no site can get consistently good bandwidth, then I'd be more likely to blame it on my ISP oversubscribing.
Re:A Full T1 is ... (Score:5, Insightful)
Re:A Full T1 is ... (Score:3, Insightful)
Downloading stuff from hundreds of hosts pretty much guarantees that it's not your link to any specific site. The aggregate download speeds should be enough to saturate the T1. The real key is doing it even at peak times. If it ever drops below 192k per second, then your ISP is overselling his upstream connection, which is something you shouldn't really tolerate when you're paying $3000/mo. (or however much T1s cost these days. It's still around there to the best of my knowledge, for full-rate non-bursted.)
If you have to ask... (Score:5, Insightful)
All reasonably priced providers will sell you shared capacity. And overselling is (usually) a question of what the other customers are doing and at what point your upwards link is going to get upgraded. You'll never get full bandwidth connectivity to the providers peering point for yourself unless you're willing to pay through the nose.
But do you really need that or are you satisfied? If you're satisfied, spending more is a waste of money, wether or not your current provider is using IP over avian carrier to connect you.