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North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: T3 Latency
Also sprach Charles Scott > Have been testing from our 7204 router and from various linux boxes. >No matter how small the packet size, we always see the 20 ms. Yes, the >total ping time to that other system is a minumum of 42 ms. Not running >ATM and have not seen any times when the latency drops below 20ms. > This may be the key. More of an effect of the way they're bringing me >in. I guess I need to ask them some specific questions. I've been watching this thread with some interest...from reading it all, my gut instinct is that some circuit provider has your circuit routed all over creation, or there's some other sub-optimal aspect of your circuit (well...I guess that's pretty obvious). The question then really becomes...how important is the latency *to you*. Clearly, 20ms latency on a 300-400 mile (as the crow flies) T3 is sub-optimal somehow. You might very well have customers and potential customers question that, because it *does* affect performance, however slightly, and it might be an indicator of other, more in depth problems. Also, if you're looking at several thousand fiber miles on a 300 mile line of sight run...that gives more opportunity for backhoe fade and other problems. Honestly, if I were in your situation, I would give some very serious thought to refusing the circuit. I would be very likely to demand that they get the circuit down to 10ms, and might even consider a demand of around 7ms before I would accept it. That, of course, is my thinking, and I don't know all the details of your situation. I believe you posted looking for input and what others thought on it though, so, FWIW, there's my $.02. Another possibility is to look into what the provider gives as far as SLA's are concerned. (I know some on the list have heard about this before...forgive me for sharing an old, though still ongoing, story again) I have a T3 between Louisville, KY and Indianapolis, IN (around 3ms latency, unloaded) that is carried by 6 different telco's. It took 7 months from time of order to get that circuit turned up. When it has gone down, it has taken no less than 18 hours to get it fixed, and the conference calls involved have typically been to the point of outright hilarity (depending on your perspective I guess). The circuit was ordered by UU.Net, and when we found out how the circuit was routed, we were sure to sign up for their SLA agreements. We have had very good luck getting SLA credits when the circuit goes down...and with the circuit typically being down for 24-30 hours...we typically gets a free month of service when it dies. I'm dumbfounded that UU.Net hasn't kicked WCOM's butt into getting this circuit groomed onto WCOM facilities in order to cut down the number of carriers to 2, but they haven't done it yet, and we keep collecting the SLA credits when it goes down, so I can deal with that...I'd rather it stay up and get fixed quicker, but a day of credit per hour of outage does tend to take the sting out of having the circuit down. Anyway...my point in that story...if the provider has SLA's that include latency provisions, it might be worthwhile to try to get it fixed by pounding on the SLA issue until they realize that its in *their* best interest to get the circuit fixed. :) -- Jeff McAdams Email: [email protected] Head Network Administrator Voice: (502) 966-3848 IgLou Internet Services (800) 436-4456
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