[j-nsp] PE-CE BGP announcements

[Jason Lixfeld]

Hello,

I’m trying to work through solving why a BGP prefix 126.126.126.0/24 announced to pe2 in vrf foo isn’t announced to EBGP neighbour 10.108.35.254 on pe1 that is also in vrf foo.

jlixfeld at pe1# run show route protocol bgp table foo.inet.0 126.126.126.0/24

foo.inet.0: 41 destinations, 51 routes (35 active, 0 holddown, 9 hidden)
+ = Active Route, - = Last Active, * = Both

126.126.126.0/24   *[BGP/170] 03:18:28, MED 0, localpref 990, from 10.15.48.253
                      AS path: 12345 I, validation-state: unverified
                    > to 10.15.51.248 via xe-0/1/5.0, Push 91
                      to 10.15.49.83 via xe-0/1/0.0, Push 91, Push 18(top)
                    [BGP/170] 03:18:28, MED 0, localpref 990, from 10.15.48.254
                      AS path: 12345 I, validation-state: unverified
                    > to 10.15.51.248 via xe-0/1/5.0, Push 91
                      to 10.15.49.83 via xe-0/1/0.0, Push 91, Push 18(top)

[edit]
jlixfeld at pe1#

126.126.126.0/24 is received from as12345 on pe2.  pe2 announces the prefix to RRs 10.15.48.253 and 10.15.48.254, and the RRs announce the prefix to pe1.  From here, I’m trying to announce it to EBGP neighbour 10.108.35.254, which I can’t seem to make work:

jlixfeld at pe1# run show route advertising-protocol bgp 10.108.35.254

foo.inet.0: 41 destinations, 51 routes (35 active, 0 holddown, 9 hidden)
  Prefix		  Nexthop	       MED     Lclpref    AS path
* 10.137.128.0/21         Self                                    I
* 10.137.136.0/21         Self                                    I
* 10.137.144.0/21         Self                                    I
* 10.137.152.0/21         Self                                    I
* 10.207.192.0/19         Self                                    I
* 10.15.48.0/22           Self                                    I
* 10.15.52.0/22           Self                                    I
* 10.15.56.0/22           Self                                    I
* 10.15.60.0/22           Self                                    I
* 10.98.192.0/20          Self                                    I
* 10.9.192.0/19           Self                                    I
* 10.45.192.0/20          Self                                    I
* 10.192.44.0/22          Self                                    I
* 10.59.160.0/20          Self                                    I
* 10.249.160.0/22         Self                                    I
* 10.68.120.0/21          Self                                    I
* 10.167.152.0/21         Self                                    I
* 10.175.212.0/22         Self                                    I
* 10.223.160.0/19         Self                                    I
* 10.253.136.0/21         Self                                    I

[edit]
jlixfeld at pe1#

(FWIW, the prefixes that are being announced are anchored on pe1 as static routes)

My understanding is that since this is a BGP prefix, it’s default export policy is to advertise all active BGP routes to all BGP speakers.  But, to try and work through whether it was an export policy issue anyway, I deactivated the export policy on the session to 10.108.35.254, which was ineffective.

Maybe there are additional default behaviours that are different than what I’m more familiar with in IOS/XR?

Maybe it is actually a policy issue, and I’m just not aware of what’s necessary for the prefix get announced.  I was hoping that there was an equivalent to show route receive-protocol bgp <neighbor> hidden table <..> detail that would show why a prefix may not be getting announced to an EBGP neighbor.  IE: this command would show the reasons why a received route is hidden, ie: "Hidden reason: rejected by import policy”.

Would someone be able to point me in the direction of where I might need to look to clear up what I’m missing?

Thanks!