Re: Juniper advertises ::/0 Cisco hears ::/3

[email protected] gwood83 at
Sat May 12 02:17:08 UTC 2012

Very interesting.  Do you know what platform and code the Juniper side on L3 is running?

Sent from my HTC on the Now Network from Sprint!

----- Reply message -----
From: "Ben Bartsch" <uwcableguy at>
Date: Fri, May 11, 2012 6:29 pm
Subject: Juniper advertises ::/0 Cisco hears ::/3
To: <nanog at>

This one is very strange...

Has anyone seen this behavior with BGP IPv6 between Juniper (owned by Level
3, advertising routes correctly, sending default ::/0) and Cisco (6509
running 12.2.58.SXI6 advipservices, receiving all routes fine except
default, hearing ::/3)?  I worked with Level 3 and they confirmed they are
sending ::/0 as default:

show route advertising-protocol bgp 2001:1900:2100::XXX

inet6.0: 11139 destinations, 43712 routes (11135 active, 0 holddown, 7

  Prefix                  Nexthop              MED     Lclpref    AS path

* ::/0                    Self                                    I

We see a ::/3:

XXXXXXX#sh ip bgp ipv6 uni neigh 2001:1900:2100::XXX received-r

BGP table version is 497237119, local router ID is XXX.XX.XX.XXXX

Status codes: s suppressed, d damped, h history, * valid, > best, i -

              r RIB-failure, S Stale

Origin codes: i - IGP, e - EGP, ? - incomplete

   Network          Next Hop            Metric LocPrf Weight Path

*> ::/3             2001:1900:2100::XXX

                                                           0 3356 i

I opened a TAC case and they had me run some IPv6 BGP detailed debugging
which confirmed we are receiving a ::/3

*May* *11* *18:01:07* *XXXXXXXXXXX* *67205:* *May* *11* *18:01:05.701* *CDT:
* *BGP*(*1*)*:* *process* *::/3*, *next* *hop* *2001:1900:2100::XXX* (*
FE80::XXXX:XXXX:XXXX:XXXX*), *metric* *0* *from* *2001:1900:2100::XXX*

Cisco's next step is for us to Wireshark the interface.  I have requested
Level 3 engage Juniper TAC, but am not expecting them to come up with
anything since they already confirmed they are sending ::/0.

We have a second connection to Level 3 that is Cisco - Cisco and it is
working fine.  My gut says this is one of those Juniper - Cisco
communications issues, but I need proof.

I am just curious if anyone has seen this type of behavior.  Have a great


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