BGP -Urgent Help needed - BGP issues with secondary ISP going down if primary goes down

[shaank257]

I have 2 ISPS conect to one router. 

ISP1 = 100MB fiber link 

ISP2 = bonded pair of t1's

The issue is no matter what type of route i try to do, If I physically unplug ISP1, nothing is able to route out from anything behind the router. I am however to ping outside so im not sure why its not routing outbound traffic.. ISP2 is for multihoming purposes of BGP but to be there as a redundany link to everything where we would be able to support our clients who have VoIP through us. 

I am not sure what the issue is, unfortunately I do not have any support system for this. Basically the way it should work is that if are Fiber goes down (which is going to happen sometime tonight as they are performing maintenance) the Bonded T1's will take over.

The config is as follows, Thank you for the help.

edundancy
!
!
controller T1 0/0/0
 cablelength long 0db
 channel-group 0 timeslots 1-24
!
controller T1 0/0/1
 cablelength long 0db
 channel-group 0 timeslots 1-24
!
ip ssh version 2
!
!
!
!         
interface Multilink1
 description T1 Backup
 bandwidth inherit
 ip address xxx.xxx.xxx.xxx 255.255.255.252

 ppp multilink
 ppp multilink group 1
!
interface Embedded-Service-Engine0/0
 no ip address
 shutdown
!
interface GigabitEthernet0/0
 description Primary
 ip address yyy.yyy.yyy.yyy 255.255.255.252
 duplex full
 speed 1000
!
interface GigabitEthernet0/1
 description WAN Switch
 ip address xxx.xxx.xxx.xxx 255.255.255.192 secondary
 ip address xxx.xxx.xxx.xxx 255.255.255.128
 duplex full
 speed 1000

!
interface GigabitEthernet0/2
 ip address xxx.xxx.xxx.xxx 255.255.255.192
 duplex full
 speed auto
!
interface Serial0/0/0:0
 description T1-1
 bandwidth 1544
 no ip address
 encapsulation ppp
 ppp multilink
 ppp multilink group 1
!
interface Serial0/0/1:0
 description T1-2
 bandwidth 1544
 no ip address
 encapsulation ppp
 ppp multilink
 ppp multilink group 1
!
router bgp #####
 bgp log-neighbor-changes
 network XXX.XXX.XXX.XXX
 neighbor xxx.xxx.xxx.xxx remote-as 111111
 neighbor xxx.xxx.xxx.xxx description PRIMARY BGP
 neighbor xxx.xxx.xxx.xxx password 7 xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
 neighbor xxx.xxx.xxx.xxx soft-reconfiguration inbound
 neighbor xxx.xxx.xxx.xxx route-map Corp-BGP-Mid-in in
 neighbor xxx.xxx.xxx.xxx route-map Corp-BGP-Mid-out out
 neighbor xxx.xxx.xxx.xxx maximum-prefix 200
 neighbor yyy.yyy.yyy.yyy remote-as 222222
 neighbor yyy.yyy.yyy.yyy description BACKUP BGP
 neighbor yyy.yyy.yyy.yyy password 7 xxxxxxxxxxxxxxx
 neighbor yyy.yyy.yyy.yyy update-source Multilink1
 neighbor yyy.yyy.yyy.yyy soft-reconfiguration inbound
 neighbor yyy.yyy.yyy.yyy route-map Corp-BGP-ACDin in
 neighbor yyy.yyy.yyy.yyy route-map Corp-BGP-ACD-out out
 neighbor yyy.yyy.yyy.yyy maximum-prefix 200
!
ip forward-protocol nd
!
no ip http server
no ip http secure-server

!
no ip nat service sip udp port 5060

ip route xxx.xxx.xxx.xxx 255.255.255.0 ###.###.###  *(Fiber Gateway)* 
ip route xxx.xxx.xxx.xxx 255.255.255.0 ###.###.###  *Bonded t1's Gateway)* 
!
!
ip prefix-list Corp-BGP-ACD-in seq 10 deny XXX.XXX.XXX.XXX/24
ip prefix-list Corp-BGP-ACD-in seq 20 permit 0.0.0.0/0
ip prefix-list Corp-BGP-ACD-in seq 30 permit 0.0.0.0/0 le 32
!
ip prefix-list Corp-BGP-ACD-out seq 10 permit XXX.XXX.XXX.XXX/24
!
ip prefix-list Corp-BGP-MidMI-in seq 10 deny XXX.XXX.XXX.XXX/24
ip prefix-list Corp-BGP-MidMI-in seq 20 permit 0.0.0.0/0
ip prefix-list Corp-BGP-MidMI-in seq 30 permit 0.0.0.0/0 le 32
!
ip prefix-list KWCorp-BGP-MidMI-out seq 10 permit XXX.XXX.XXX.XXX/24
!
route-map Corp-BGP-MidMI-in permit 10
 match ip address prefix-list Corp-BGP-MidMI-in
 set local-preference 110
!
route-map Corp-BGP-ACD-in permit 10
 match ip address prefix-list Corp-BGP-ACD-in
!
route-map Corp-BGP-MidMI-out permit 10
 match ip address prefix-list Corp-BGP-MidMI-out
!
route-map Corp-BGP-ACD-out permit 10
 match ip address prefix-list Corp-BGP-ACD-out
 set as-path prepend 111111 111111 111111
!
!
!
!

[paul driver]

Hello

At first glance looks like you have no IGP running so the BGP is using the static routes for reachability,

So even though you have disconnected the interconnect to ISP1 the static route is still pointing out towards ISP1 lan interface .so traffic is black holing.

Using a floating static route tide in with either tracking the interface or monitoring a remote route prefix so when ISP goes down or the prefix becomes unavailable its relating tracked default route will be removed from the rib and failover towards the ISP2 default route.

I would suggest try something like this:

track 10 interface GigabitEthernet0/0line-protocol

or

ip sla 10
icmp-echo y.y.y.y source-ip x.x.x.x
timeout 2000
frequency 5

ip sla schedule 10 life forever start-time now

track 10 rtr 10 reachability

ip route xxx.xxx.xxx.xxx 255.255.255.0 ###.###.### *(Fiber Gateway)* track 10

ip route xxx.xxx.xxx.xxx 255.255.255.0 ###.###.### *Bonded t1's Gateway)* 4 (admin distance)

res
Paul