nanog mailing list archives

Re: Comcast NOC - Bad IPv6 Routing


From: Ross Tajvar <ross () tajvar io>
Date: Sat, 15 Feb 2020 23:45:16 -0500

Interesting - does a v4 traceroute follow the same path? I.e. Richmond CRAN
-> ibone Atlanta -> ibone Ashburn -> Pitt CRAN

Not having detailed knowledge of Comcast's network, I'd expect the Richmond
CRAN has a link to the ibone in Ashburn since it's fairly close (though
there may be a closer ibone location).

On Sat, Feb 15, 2020, 11:11 PM Robert Webb <rwfireguru () gmail com> wrote:

Could someone from Comcast NOC contact me off list.

Looks like IPv6 routing from Richmond, VA to Grafton, WV has issues. IPSEC
tunnel between gets less than 5Mbps over IPv6, switching endpoints to IPv4,
I get the full 25Mbps down capability of the WV connection.

Traceroute looks like below:

Tracing route to 2001:558:6035:3c:79bb:f773:ab2:6bcd over a maximum of 30
hops

  1    <1 ms    <1 ms    <1 ms  2601:5ca:c301:4c90::1
  2    11 ms    11 ms    10 ms  2001:558:4053:b::1
  3     7 ms     7 ms     8 ms  2001:558:182:112::1
  4    20 ms     9 ms     9 ms
ae-45-ar02.staplesmllrd.va.richmond.comcast.net [2001:558:180:2005::1]
  5    26 ms    30 ms    24 ms
be-21508-cr02.56marietta.ga.ibone.comcast.net [2001:558:0:f787::1]
  6    22 ms     *       23 ms
be-1202-cs02.56marietta.ga.ibone.comcast.net [2001:558:3:12::1]
  7     *       28 ms     *
be-1211-cr11.56marietta.ga.ibone.comcast.net [2001:558:3:2::2]
  8     *        *        *     Request timed out.
  9     *        *        *     Request timed out.
 10    36 ms     *        *     be-1402-cr02.ashburn.va.ibone.comcast.net
[2001:558:3:2d::2]
 11     *        *        *     Request timed out.
 12    39 ms    43 ms    42 ms  2001:558:380:29c::2
 13    42 ms    45 ms    50 ms  te-5-1-0-cbr01.taylor.wv.pitt.comcast.net
[2001:558:382:fe58::2]
 14     *        *        *     Request timed out.
 15     *        *        *     Request timed out.
 16     *        *        *     Request timed out.




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