RE: BGP routes can't learn from PE to CE

From: Huan Pham (Huan.Pham@peopletelecom.com.au)
Date: Tue Aug 05 2008 - 01:55:41 ART


Hi,

You'd better post full config, or additional show output, e.g.

Show ip bgp summ,
Show ip bgp
show ip bgp nei x.x.x.x receive-route

Assumming that BGP between CE-PE are OK, and CE1 got routes advertized
from PE1, but cannot install them in the routing table, then most likely
it's because CE do not have routes to the next hop (PE2 IP).

Try the following, and see how you go from there:

PE1#
router bgp 64512
 address-family ipv4 vrf one
 neighbor 172.16.1.2 remote-as 64513

! You need this
 neighbor 172.16.1.2 next-hop-self

! And maybe add the following on both PE1, PE2, if you use same AS 64513
on CE2
 neighbor 172.16.1.2 as-override

 

-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
CCIE GURU
Sent: Tuesday, 5 August 2008 2:14 PM
To: Cisco certification
Subject: BGP routes can't learn from PE to CE

Hello all gentelman!

Here is my topology.And I am trying to build MPLS VPN. I want to
advertise routes from both CEs to each other across MPLS backbone.

CE1------PE1-----Core1------Core2------PE2------CE2

PE & CE are eBGP neighbor.

Route from CE2 advertise to until PE1. But PE1 seems don't re-advertise
route from CE2 to CE1.

PE1#sh ip bgp vpnv4 all neighbors 172.16.1.2 advertised-routes BGP table
version is 10, local router ID is 1.1.1.3 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
Route Distinguisher: 64512:1 (default for vrf one)
*>i1.1.1.6/32 1.1.1.4 0 100 0 64513 ?
*>i172.16.2.0/30 1.1.1.4 0 100 0 64513 ?
Total number of prefixes 2

*Sh ip route on PE1*

PE1#sh ip route vrf one
Routing Table: one
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS
level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static
route
       o - ODR, P - periodic downloaded static route Gateway of last
resort is not set
     1.0.0.0/32 is subnetted, 2 subnets
B 1.1.1.5 [20/0] via 172.16.1.2, 00:22:14
B 1.1.1.6 [200/0] via 1.1.1.4, 00:22:14
     172.16.0.0/30 is subnetted, 2 subnets
C 172.16.1.0 is directly connected, FastEthernet1/0
B 172.16.2.0 [200/0] via 1.1.1.4, 00:22:14
PE1#

*Here is PE1 config*

PE1#sh run | b router bgp
router bgp 64512
 no bgp default ipv4-unicast
 bgp log-neighbor-changes
 neighbor 1.1.1.4 remote-as 64512
 neighbor 1.1.1.4 update-source Loopback0 !
 address-family ipv4
 neighbor 1.1.1.4 activate
 no auto-summary
 no synchronization
 exit-address-family
 !
 address-family vpnv4
 neighbor 1.1.1.4 activate
 neighbor 1.1.1.4 send-community extended exit-address-family !
 address-family ipv4 vrf one
 neighbor 172.16.1.2 remote-as 64513
 neighbor 172.16.1.2 activate
 no auto-summary
 no synchronization
 exit-address-family

*CE verify*
**
CE1#sh ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS
level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static
route
       o - ODR, P - periodic downloaded static route Gateway of last
resort is not set
     1.0.0.0/32 is subnetted, 1 subnets
C 1.1.1.5 is directly connected, Loopback0
     172.16.0.0/30 is subnetted, 1 subnets
C 172.16.1.0 is directly connected, FastEthernet0/0

Please adivce.
Regards

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