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How to Test Your T1?
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!"
Maybe you could use a packet sniffer and see if you are getting other stuff on your line. If you are, then it's not a true T1.
If you're getting T1 service, it should be possible to borrow a CSU/DSU, put it in remote-loopback, and make sure you have a full T1 of bandwidth. Or, if you own the router, you can just look at the statistics...
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.
An ISP that I know fairly well (*cough* work for *cough*) oversells bandwidth. They use mrtg (as has been suggested elsewhere) and any time a network segment reaches 80% utilization at any point in the day, three days in a row, that segment is upgraded.
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.
None of those methods will work. Ping flood point-to-point will always max out the pipe. It doesn't test the effective bandwidth that you have to the public internet or other backbone providers. The same goes for FTP'ing a file from their POP. The true way to test is to download 100 files from 100 different machines on the internet and tally up the total bytes/sec. If you don't come up to 192k/s during peak hours, you're getting screwed.
That's it. I'm no longer part of Team Sanity.
If no site can get consistently good bandwidth, then I'd be more likely to blame it on my ISP oversubscribing.
Free Software: Like love, it grows best when given away.
The point of testing an FTP download to the T1 providers POP is to test the LINE, not the other guys lines as you suggested by going to 100 other servers. What the person is interested in is the bandwidth provided on his "T1".
Moderators, please read the parent post and consider modding him up. It's the only response I can see that actually answers the guy's question. THIS is the number the guy in the article is looking for.
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.)
Random and weird software I've written.
... why do you really care? If you're getting the service you need, why bother? If you're satisfied with the current bandwidth and ping times through your T1, why buy something more expensive even if it is faster/less congested/has blinkity blinky florbs?
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.