Need help

adriansizemore

I am stuck. I had pe to ce ebgp configured yesterday, but my configs did save via gns3 for some reason. So, to day I reapplied everything and I cant get my ebgp session to come up. Below are the configs:


CE

router bgp 65102
no synchronization
bgp log-neighbor-changes
redistribute static
neighbor 172.16.1.6 remote-as 65400
neighbor 172.16.1.6 update-source Loopback0
no auto-summary
!
ip http server
no ip http secure-server
ip forward-protocol nd
ip route 0.0.0.0 0.0.0.0 FastEthernet0/1

cu1a(config-router)#do sh ip bgp ne
BGP neighbor is 172.16.1.6, remote AS 65400, external link
BGP version 4, remote router ID 0.0.0.0
BGP state = Active
Last read 00:17:21, last write 00:17:21, hold time is 180, keepalive interval is 60 seconds
Message statistics:
InQ depth is 0
OutQ depth is 0
Sent Rcvd
Opens: 0 0
Notifications: 0 0
Updates: 0 0
Keepalives: 0 0
Route Refresh: 0 0
Total: 0 0
Default minimum time between advertisement runs is 30 seconds

For address family: IPv4 Unicast
BGP table version 1, neighbor version 0/0
Output queue size : 0
Index 1, Offset 0, Mask 0x2
1 update-group member
Sent Rcvd
Prefix activity: ---- ----
Prefixes Current: 0 0
Prefixes Total: 0 0
Implicit Withdraw: 0 0
Explicit Withdraw: 0 0
Used as bestpath: n/a 0
Used as multipath: n/a 0

Outbound Inbound
Local Policy Denied Prefixes:

---

---

Total: 0 0
Number of NLRIs in the update sent: max 0, min 0

Connections established 0; dropped 0
Last reset never
No active TCP connection

cu1a(config-router)# do ping 172.16.1.6

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 172.16.1.6, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 4/10/24 ms
cu1a(config-router)#

cu1a#sh ip rout

Gateway of last resort is 0.0.0.0 to network 0.0.0.0

172.16.0.0/30 is subnetted, 1 subnets
C 172.16.1.4 is directly connected, FastEthernet0/1
12.0.0.0/32 is subnetted, 1 subnets
C 12.0.0.3 is directly connected, Loopback0
S* 0.0.0.0/0 is directly connected, FastEthernet0/1


PE


address-family ipv4 vrf cu1a
redistribute connected
neighbor 172.16.1.5 remote-as 65102
neighbor 172.16.1.5 update-source Loopback1
neighbor 172.16.1.5 activate
no synchronization
exit-address-family


p2# sh ip bgp v v cu1a nei
BGP neighbor is 172.16.1.5, vrf cu1a, remote AS 65102, external link
BGP version 4, remote router ID 0.0.0.0
BGP state = Active
Last read 00:04:31, last write 00:04:31, hold time is 180, keepalive interval is 60 seconds
Message statistics:
InQ depth is 0
OutQ depth is 0
Sent Rcvd
Opens: 0 0
Notifications: 0 0
Updates: 0 0
Keepalives: 0 0
Route Refresh: 0 0
Total: 0 0
Default minimum time between advertisement runs is 30 seconds

For address family: VPNv4 Unicast
Translates address family IPv4 Unicast for VRF cu1a
BGP table version 5, neighbor version 0/0
Output queue size : 0
Index 1, Offset 0, Mask 0x2
1 update-group member
Sent Rcvd
Prefix activity: ---- ----
Prefixes Current: 0 0
Prefixes Total: 0 0
Implicit Withdraw: 0 0
Explicit Withdraw: 0 0
Used as bestpath: n/a 0
Used as multipath: n/a 0

Outbound Inbound
Local Policy Denied Prefixes:

---

---

Total: 0 0
Number of NLRIs in the update sent: max 0, min 0

Connections established 0; dropped 0
Last reset never
No active TCP connection



p2#sho ip route vrf cu1a

Routing Table: cu1a


172.16.0.0/30 is subnetted, 1 subnets
C 172.16.1.4 is directly connected, FastEthernet1/0

---

I have not configured the m-ibgp sessions yet. I am waiting to get my pe to ce connections up first. Any thoughts?

networker050184

Can you post the entire BGP config fro the PE?

adriansizemore

router bgp 65400
bgp log-neighbor-changes
neighbor 13.0.0.1 remote-as 65400
neighbor 13.0.0.1 update-source Loopback0
!
address-family ipv4
neighbor 13.0.0.1 activate
no auto-summary
no synchronization
exit-address-family
!
address-family vpnv4
neighbor 13.0.0.1 activate
neighbor 13.0.0.1 send-community extended
exit-address-family
!
address-family ipv4 vrf cu1a
redistribute connected
neighbor 172.16.1.5 remote-as 65102
neighbor 172.16.1.5 update-source Loopback2
neighbor 172.16.1.5 activate
neighbor 172.16.1.5 send-community both
no synchronization
exit-address-family

networker050184

Add the neighbor under router bgp and not just the address family.

adriansizemore

the neighbor under the global bgp configuration is for the ibgp sessions across the cloud. since i have an interface configured with vrf forwarding, the neighbor statement in the address family should be for the ebgp session to the ce

networker050184

Ah, got you.

Do you have a route to the other routers loopback? You need a specific route also, not a default route.

adriansizemore

if i redistribute connected, doesnt that suffice for bgp?

networker050184

Well, it can't get the BGP route until the neighbor is up, so not in this situation.

Try using a static route or using the outgoing interface as the update source.

adriansizemore

p2(config-router-af)#do sh ip vrf int
Interface IP-Address VRF Protocol
Fa1/0 172.16.1.6 cu1a up
p2(config-router-af)#do sh run | b address-
address-family ipv4 vrf cu1a
redistribute connected
neighbor 172.16.1.5 remote-as 65102
neighbor 172.16.1.5 update-source Loopback2
neighbor 172.16.1.5 activate
no synchronization
exit-address-family

networker050184

Either get rid of update-source loopback2 or give a static route to the loopback on the other router. Usually with EBGP you would just use the exit interface anyway.

adriansizemore

so,

I would get rid of the update loop back and add a static route to the pe-ce interface? Trying it right now!

adriansizemore

I think i got what you are saying. takes me back to my bgp basics days. If we build the ebgp session to a loopback, then we update source loopback, otherwise, we build a static route to the pe-ce interface

adriansizemore

adriansizemore wrote: »

I think i got what you are saying. takes me back to my bgp basics days. If we build the ebgp session to a loopback, then we update source loopback, otherwise, we build a static route to the pe-ce interface

I am up. Thanks for the help

PE
p2#sho ip bgp v v cu1a summary
BGP router identifier 13.0.0.2, local AS number 65400
BGP table version is 7, main routing table version 7

Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
172.16.1.5 4 65102 4 14 7 0 0 00:00:57 0


CE
cu1a#show ip bgp summary
BGP router identifier 12.0.0.3, local AS number 65102
BGP table version is 1, main routing table version 1

Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
172.16.1.6 4 65400 4 4 1 0 0 00:00:45 0
cu1a#



Here is what I learned:

BGP basics still apply. They be configured slightly different, but work the same nevertheless.

networker050184

Another thing to remember if you use the loopbacks for the eBGP peering is that you have to use multihop as well.

adriansizemore

I dont think multihop is supported by multi-protocol bgp, "MPLS and VPN Architectures", Chapter 10, Page 211, Under Note