nanog mailing list archives

Large RTT or Why doesn't my ping traffic get discarded?


From: Jason Iannone <jason.iannone () gmail com>
Date: Wed, 21 Dec 2022 11:10:13 -0600

Here's a question I haven't bothered to ask until now. Can someone please
help me understand why I receive a ping reply after almost 5 seconds? As I
understand it, buffers in SP gear are generally 100ms. According to my math
this round trip should have been discarded around the 1 second mark, even
in a long path. Maybe I should buy a lottery ticket. I don't get it. What
is happening here?

Jason

64 bytes from 4.2.2.2: icmp_seq=392 ttl=54 time=4834.737 ms
64 bytes from 4.2.2.2: icmp_seq=393 ttl=54 time=4301.243 ms
64 bytes from 4.2.2.2: icmp_seq=394 ttl=54 time=3300.328 ms
64 bytes from 4.2.2.2: icmp_seq=396 ttl=54 time=1289.723 ms
Request timeout for icmp_seq 400
Request timeout for icmp_seq 401
64 bytes from 4.2.2.2: icmp_seq=398 ttl=54 time=4915.096 ms
64 bytes from 4.2.2.2: icmp_seq=399 ttl=54 time=4310.575 ms
64 bytes from 4.2.2.2: icmp_seq=400 ttl=54 time=4196.075 ms
64 bytes from 4.2.2.2: icmp_seq=401 ttl=54 time=4287.048 ms
64 bytes from 4.2.2.2: icmp_seq=403 ttl=54 time=2280.466 ms
64 bytes from 4.2.2.2: icmp_seq=404 ttl=54 time=1279.348 ms
64 bytes from 4.2.2.2: icmp_seq=405 ttl=54 time=276.669 ms

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