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

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1

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
hidden)

  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 -
internal,

              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
weekend.

-Ben

2

Just stab in the dark.

Verify that you're not disagreeing on SAFI.

If JNPR is sending labeled SAFI and you are expecting to receiving
unlabeled unicast SAFI. Then '3' from JNPR as 'implict null' would to
you mean prefix lenght.

Obviously it should fail harder, but I've seen IOS<->IOS reporting
SAFI to be one, but coding NLRI as if SAFI was something else.

3

Hi,

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:

I have seen this exact problem between two Cisco routers (c7600 sending default route, c7200 receiving ::/3), so I am not sure it's related to the Juniper box... It happened after I changed the BGP timers on the 7200, and it disappeared after removing the timer settings *and rebooting the 7200*.

- Sander