[outages] Level 3 issues
Jeremy Chadwick
jdc at koitsu.org
Tue Jan 22 15:45:14 EST 2013
1. Usually Level 3-owned routers use ICMP prioritisation; routing
(forwarding) has priority over this.
2. Many traceroute implementations use UDP for their probe packets (in
attempt to solicit ICMP TTL exceeded messages to learn the network
topology); please make sure you're using pure ICMP all the way through
if possible.
3. Your below traces indicate a destination IP of 64.208.27.65, which is
not sufficient (ICMP prioritisation will be used to explain what you're
seeing, even if there is a real issue). Please pick a destination IP of
an actual host that's somewhere behind that router which will respond to
ICMP packets reliably.
You need to see if the packet loss "trickles downward" past that hop to
every subsequent hop after that point (including the destination host),
or if high latency, if the latency "trickles downward" as well.
Here's an example of a bogus claim as a result of ICMP prio:
=== Mon Jan 21 01:39:00 PST 2013 (1358761140)
HOST: icarus.home.lan Loss% Snt Rcv Last Avg Best Wrst
1.|-- 192.168.1.1 0.0% 40 40 0.3 0.3 0.2 0.4
2.|-- 67.180.84.1 0.0% 40 40 21.8 23.0 11.2 35.4
3.|-- 68.85.191.249 0.0% 40 40 10.1 9.8 8.1 14.2
4.|-- 69.139.198.82 0.0% 40 40 21.0 17.2 9.9 22.8
5.|-- 68.86.90.93 0.0% 40 40 23.1 19.2 11.8 30.3
6.|-- 68.86.87.190 15.0% 40 34 22.3 25.9 19.9 122.6
7.|-- 75.149.231.238 37.5% 40 25 56.3 26.5 20.0 56.3
8.|-- 67.199.135.102 0.0% 40 40 21.1 25.8 20.9 49.0
9.|-- 206.125.172.42 0.0% 40 40 20.7 21.3 19.8 22.5
=== END
While here's a real issue:
=== Fri Jan 4 07:27:00 PST 2013 (1357313220)
HOST: icarus.home.lan Loss% Snt Rcv Last Avg Best Wrst
1.|-- 192.168.1.1 0.0% 40 40 0.2 0.3 0.2 0.4
2.|-- 67.180.84.1 92.5% 40 3 16.0 16.7 11.5 22.7
3.|-- 68.85.191.249 92.5% 40 3 9.4 9.3 8.7 9.7
4.|-- 69.139.198.82 90.0% 40 4 19.1 23.0 12.6 39.2
5.|-- 68.86.90.93 90.0% 40 4 12.4 14.8 12.4 17.5
6.|-- 68.86.87.190 90.0% 40 4 48.3 28.6 21.6 48.3
7.|-- 75.149.231.238 90.0% 40 4 32.7 23.9 20.4 32.7
8.|-- 67.199.135.102 90.0% 40 4 145.7 52.5 21.3 145.7
9.|-- 206.125.172.42 90.0% 40 4 20.8 21.3 19.9 22.4
=== END
All of this is covered here (read do not skim):
http://www.nanog.org/meetings/nanog47/presentations/Sunday/RAS_Traceroute_N47_Sun.pdf
--
| Jeremy Chadwick jdc at koitsu.org |
| UNIX Systems Administrator http://jdc.koitsu.org/ |
| Mountain View, CA, US |
| Making life hard for others since 1977. PGP 4BD6C0CB |
On Tue, Jan 22, 2013 at 11:40:39AM -0600, Jeremie Chism wrote:
> Seeing intermittent issues with level 3 router at 64.208.27.65
>
> Hop (ms) (ms) (ms) IP Address Host name
> 1 0 0 0 8.9.232.73 xe-5-3-0.edge3.dallas1.level3.net
> 2 0 0 0 4.69.145.141 ae-3-80.edge4.dallas3.level3.net
> 3 8 0 0 4.68.63.146 gblx-level3-40g.dallas3.level3.net
> 4 0 0 0 67.16.150.190 ae2-80g.csr1.dal2.gblx.net
> 5 0 0 0 64.208.27.65 te1-3-10g.ar3.dal2.gblx.net
>
> Hop (ms) (ms) (ms) IP Address Host name
> 1 1 0 0 8.9.232.73 xe-5-3-0.edge3.dallas1.level3.net
> 2 0 0 0 4.69.145.141 ae-3-80.edge4.dallas3.level3.net
> 3 0 0 0 4.68.63.146 gblx-level3-40g.dallas3.level3.net
> 4 0 0 0 67.16.150.190 ae2-80g.csr1.dal2.gblx.net
> 5 7 1 208 64.208.27.65 te1-3-10g.ar3.dal2.gblx.net
> Trace complete
>
> Ping times from 8ms to 330ms.
>
> --
> Jeremie Chism
> Triton Communications
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