plea for comcast/sprint handoff debug help
Randy Bush
randy at psg.com
Wed Oct 28 13:18:17 UTC 2020
tl;dr:
comcast: does your 50.242.151.5 westin router receive the announcement
of 147.28.0.0/20 from sprint's westin router 144.232.9.61?
details:
3130 in the westin announces
147.28.0.0/19 and
147.28.0.0/20
to sprint, ntt, and the six
and we want to remove the /19
when we stop announcing the /19, a traceroute to comcast through sprint
dies at the handoff from sprint to comcast.
r0.sea#traceroute 73.47.196.134 source 147.28.7.1
Type escape sequence to abort.
Tracing the route to c-73-47-196-134.hsd1.ma.comcast.net (73.47.196.134)
VRF info: (vrf in name/id, vrf out name/id)
1 r1.sea.rg.net (147.28.0.5) 0 msec 1 msec 0 msec
2 sl-mpe50-sea-ge-0-0-3-0.sprintlink.net (144.232.9.61) [AS 1239] 1 msec 1 msec 0 msec
3 * * *
4 * * *
5 * * *
6 * * *
this would 'normally' (i.e. when the /19 is announced) be
r0.sea#traceroute 73.47.196.134 source 147.28.7.1
Type escape sequence to abort.
Tracing the route to c-73-47-196-134.hsd1.ma.comcast.net (73.47.196.134)
VRF info: (vrf in name/id, vrf out name/id)
1 r1.sea.rg.net (147.28.0.5) 0 msec 1 msec 0 msec
2 sl-mpe50-sea-ge-0-0-3-0.sprintlink.net (144.232.9.61) [AS 1239] 1 msec 0 msec 1 msec
3 be-207-pe02.seattle.wa.ibone.comcast.net (50.242.151.5) [AS 7922] 1 msec 0 msec 0 msec
4 be-10847-cr01.seattle.wa.ibone.comcast.net (68.86.86.225) [AS 7922] 1 msec 1 msec 2 msec
etc
specifically, when 147.28.0.0/19 is announced, traceroute from
147.28.7.2 through sprint works to comcast. withdraw 147.28.0.0/19,
leaving only 147.28.0.0/20, and the traceroute enters sprint but fails
at the handoff to comcast. Bad next-hop? not propagated? covid?
magic?
which is why we wonder what comcast (50.242.151.5) hears from sprint at
that handoff
note that, at the minute, both the /19 and the /20 are being announced,
as we want things to work. so you will not be able to reproduce.
so, comcast, are you receiving the announcement of the /20 from sprint?
with a good next-hop?
randy
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