Comcast NOC - Bad IPv6 Routing

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1

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.

2

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).

3

IPv4 looks like I would expect traversing Charlottesville, VA then to Ashburn, VA. This is what I am used to seeing.

Tracing route to 73.214.xxx.xxx
over a maximum of 30 hops:

1 <1 ms <1 ms <1 ms 192.168.1.1
2 7 ms 11 ms 9 ms 96.120.80.37
3 7 ms 9 ms 7 ms 69.139.186.137
4 18 ms 16 ms 17 ms ae-45-ar02.charlvilleco.va.richmond.comcast.net [69.139.206.9]
5 20 ms 18 ms 20 ms be-21508-cr02.ashburn.va.ibone.comcast.net [68.86.91.53]
6 24 ms 24 ms 25 ms be-7922-ar01.mckeesport.pa.pitt.comcast.net [68.86.91.26]
7 31 ms 29 ms 29 ms 162.151.64.58
8 30 ms 30 ms 30 ms te-5-1-1-cbr01.taylor.wv.pitt.comcast.net [96.108.132.94]
9 36 ms 36 ms 40 ms c-73-214-26-90.hsd1.wv.comcast.net [73.214.xxx.xxx]

IPv6 routing still horrible this morning.