Redistribution of iBGP and eBGP

[luqman_khalid]

NW Diagramfrom PC i can ping ISP on loop back 8.8.8.8 via site A, but when i

Shutdown F0/1 of SITE-A , i cannot ping ISP from PCs.

Actually i want to switch traffic to SITE-B , if SITE-A's link is down.

PCs can ping SITE-B ip Address 192.168.1.2 but cannot ping f0/0 of SITE-B.

ISP and SITE-B can learn routes of PCs but cannot ping them,

I think problem is redistribution of ibgp and ebgp.

AS of ISP = 17557

AS of Site-A and B = 65468.

Please help

#bgp

#ibgp

#ebgp

[balaji.bandi]

Can you post ISP, A and B router config

or refer below document for reference to fix the issue :

https://www.cisco.com/c/en/us/support/docs/ip/border-gateway-protocol-bgp/13762-40.html

https://networklessons.com/cisco/ccie-routing-switching-written/bgp-multipath-load-sharing-ibgp-and-ebgp

[Georg Pauwen]

Hello,

you posted this problem earlier this morning and then removed the discussion. Your switch LAB-SW was used as a layer 3 switch, is it participating in BGP as well ?

I remember noticing that you missed the below in your iBGP neighbor configuration, try and add this and check if the failover works then:

SITE-A

neighbor 192.168.1.2 next-hop-self

SITE-B

neighbor 192.168.1.1 next-hop-self

In any case, repost the full configs of all four devices (the three routers and the switch.

[luqman_khalid]

no BGP is not enabled on L3 switch. next-hop-self didnot work , i have already tried.

[luqman_khalid]

not working with next-hop-self 

[paul driver]

Hello

Using the weight PA wont take any affect when you have ibgp peering also deactivate synchronization, append the following and test again

ISP
router bgp 17557
network 8.8.8.8 mask 255.255.255.255
network 58.181.114.168 mask 255.255.255.252
network 221.120.214.176 mask 255.255.255.252
no redistribute static <-- not required
no neighbor 221.120.214.178 allowas-in <-- not required

Site A
router bgp 65468
neighbor 192.168.1.2 next-hop self
address-family ipv4
no neighbor 192.168.1.2 soft-reconfiguration inbound <-- not required
no neighbor 221.120.214.177 soft-reconfiguration inbound <-- not required
no synchronization
network 192.168.1.0
bgp default local-preference 500
redistribute static
exit

clear ip bgp soft *

Site B
router bgp 65468
neighbor 192.168.1.1 next-hop self
address-family ipv4
no neighbor 58.181.114.77 weight 90  <-- not required
no neighbor 192.168.1.2 soft-reconfiguration inbound <-- not required
no neighbor 221.120.214.177 soft-reconfiguration inbound <-- not required
no synchronization
network 192.168.1.0

clear ip bgp soft *

[luqman_khalid]

no working with this also

[Georg Pauwen]

Hello,

I could not even get to 8.8.8.8 from anywhere with announcing the network in BGP on the ISP router, not sure if that was the problem. Either way, my working configs are below:

ISP

router bgp 17557
bgp log-neighbor-changes
neighbor 58.181.114.78 remote-as 65468
neighbor 221.120.214.178 remote-as 65468
!
address-family ipv4
network 8.8.8.8 mask 255.255.255.255
redistribute static
neighbor 58.181.114.78 activate
neighbor 58.181.114.78 weight 100
neighbor 58.181.114.78 soft-reconfiguration inbound
neighbor 221.120.214.178 activate
neighbor 221.120.214.178 weight 200
neighbor 221.120.214.178 allowas-in
neighbor 221.120.214.178 soft-reconfiguration inbound
exit-address-family

SITE-A

router bgp 65468
bgp log-neighbor-changes
neighbor 192.168.1.2 remote-as 65468
neighbor 221.120.214.177 remote-as 17557
!
address-family ipv4
network 221.120.24.192 mask 255.255.255.252
network 221.120.24.196 mask 255.255.255.252
network 221.120.212.64 mask 255.255.255.252
neighbor 192.168.1.2 activate
neighbor 192.168.1.2 next-hop-self
neighbor 192.168.1.2 soft-reconfiguration inbound
neighbor 221.120.214.177 activate
neighbor 221.120.214.177 soft-reconfiguration inbound
exit-address-family

SITE-B

router bgp 65468
bgp log-neighbor-changes
neighbor 58.181.114.77 remote-as 17557
neighbor 192.168.1.1 remote-as 65468
!
address-family ipv4
neighbor 58.181.114.77 activate
neighbor 192.168.1.1 activate
neighbor 192.168.1.1 next-hop-self
neighbor 192.168.1.1 soft-reconfiguration inbound
exit-address-family

[paul driver]

---

@luqman_khalid wrote:
no working with this also

---

The config i posted above should work, Probably decrease the BGP timers and test again

all rtrs
router bgp xxx
timers bgp 3 10
exit

clear ip bgp *