I got several replies,, and I investigated it more. We are using tiered T3 service from uu.net, and I suspect that uu.net use ATM QoS scheme between hop 4 and hop 5. (We are using 30 Mbps from uu.net) (But, I knew that the way of tiered bandwidth was using control of CSU -LARSCOM-.) Is it true that uu.net use ATM QoS scheme (i.e. rate control by leaky bucket algorithm) for shaping bandwidth ? When the link has avaible bandwidth, the response time of PING is much faster. But the RTT of PING is slow when the link goes to peak rate. --But there are no *packet loss*-- I think it is similar to *rate control*. Is there any comments ? ---Jaeho Yang. Harold Willison wrote:
At 03:49 PM 9/16/98 +0900, you wrote:
Hello,
I want to hear advices from gurus,,
Our network use transit service from UU.NET in PaloAlto IX.
## the result of traceroute from our network to www.sun.com traceroute to Sun.COM (192.9.49.33), 30 hops max, 40 byte packets --<snip>-- 4 INET-PA-GW.nuri.net (203.235.119.253) 147 ms 145 ms 143 ms 5 911.Hssi5-0.GW1.PAO1.ALTER.NET (157.130.192.145) 170 ms 169 ms 173 ms <-----@@@@ 6 119.ATM3-0.XR1.SCL1.ALTER.NET (146.188.144.78) 486 ms 434 ms 441 ms <-----@@@@ 7 146.188.145.157 (146.188.145.157) 432 ms 440 ms 443 ms 8 core7-hssi5-0.SanFrancisco.mci.net (206.157.77.73) 408 ms 457 ms 425 ms --<snip>--
I would suggest getting UUnet to do perform 2 traceroutes back to your originating address.
The problem could be that when your traffic hits hop 6 it has a different return route which has poorer performance. If UUnet performs the traceroutes from the hop 5 and hop 6 routers towards you you will see the path both takes. If they are both the same path then it would definately appear to be a problem on their link. If the route back from hop 5 is different than from hop 4 I would suggest checking for the problem spot in that traceroute.
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