c1sc0m4n
asked on
BGP with ISDN Backup
I have a problem with BGP and ISDN backup. What I want to achive is:
1. When the main link fails (in this case Frame Relay) - the eBGP route dies and I have a floating static with AD 200 pointing to Dialer1.
2. I then want Dialer 1 to dial the Main HQ Router - which it does.
3. I want the main link to then come back up - and for the peering to est and for the route from centre to come accross Frame Relay main link to Remote (this router). Which it doesnt????
Does anyone know why. I have denied BGP on the BRI interface and Dialer with an ACL (so that BGP doesnt keep the ISDN link up - like a passive-interface command in EIGRP - which you cant have on BGP).
Can anyone help???
1. When the main link fails (in this case Frame Relay) - the eBGP route dies and I have a floating static with AD 200 pointing to Dialer1.
2. I then want Dialer 1 to dial the Main HQ Router - which it does.
3. I want the main link to then come back up - and for the peering to est and for the route from centre to come accross Frame Relay main link to Remote (this router). Which it doesnt????
Does anyone know why. I have denied BGP on the BRI interface and Dialer with an ACL (so that BGP doesnt keep the ISDN link up - like a passive-interface command in EIGRP - which you cant have on BGP).
Can anyone help???
ASKER
Yeh basically when main WAN link is restored (bareing in mind that I have continuous ping between two laptops) the ISDN just will not cancel call and re route traffic.
Yep main s0 int comes up fine
Im using IP unnumbered with loopback 0 - can ping fine
Route is still same: B x.x.x.x/24 [20/0] via 172.16.1.10, 00:19:26
Intresting - if i turn cont ping off - therefore no traffic over isdn - isdn shuts BRI/Dialer int down and traffic will then go over Serial 0 with no problems and without re-opening isdn call.
I too have had EIGRP working perfectly like this - i think its a weird BGP thing and maybe timers or something???
Configs are as follows:
Centre:
Current configuration : 2178 bytes
!
version 12.3
service timestamps debug uptime
service timestamps log uptime
service password-encryption
!
hostname Tipton
!
boot-start-marker
boot-end-marker
!
username France password 7 123456
no aaa new-model
ip subnet-zero
no ip domain lookup
!
frame-relay switching
isdn switch-type basic-net3
!
interface Loopback0
ip address 172.16.1.10 255.255.255.255
!
interface Loopback1
no ip address
!
interface Ethernet0
description Ethernet Interface to Paris LAN
ip address x.x.x.x 255.255.255.0
!
interface Serial0
no ip address
encapsulation frame-relay IETF
no fair-queue
frame-relay lmi-type ansi
frame-relay intf-type dce
!
interface Serial0.1 point-to-point
ip unnumbered Loopback0
no cdp enable
frame-relay interface-dlci 101
!
interface BRI0
description ISDN Backup to Tipton
ip unnumbered Loopback0
encapsulation ppp
dialer pool-member 1
isdn switch-type basic-net3
ppp authentication chap
ppp multilink
!
interface Dialer1
description Dialer to Tipton
ip unnumbered Loopback0
encapsulation ppp
dialer pool 1
dialer remote-name France
dialer idle-timeout 60
dialer string 532 (internal PBX)
dialer load-threshold 5 either
dialer-group 1
ppp multilink
!
router bgp 100
no synchronization
bgp log-neighbor-changes
network x.x.x.x
neighbor 172.16.1.40 remote-as 400
neighbor 172.16.1.40 ebgp-multihop 255
neighbor 172.16.1.40 update-source Loopback0
no auto-summary
!
ip route 0.0.0.0 0.0.0.0 1.1.1.1
ip route x.x.x.x 255.255.255.0 Dialer1 200
!
access-list 100 permit ip any any
access-list 101 deny tcp any any eq bgp
dialer-list 1 protocol ip list 100
!
!
access-list 100 permit ip any any
access-list 101 deny tcp any any eq bgp - not applied but has been and still the same :-(
access-list 101 permit ip any any
dialer-list 1 protocol ip list 100
Vice Versa for Remote.
Yep main s0 int comes up fine
Im using IP unnumbered with loopback 0 - can ping fine
Route is still same: B x.x.x.x/24 [20/0] via 172.16.1.10, 00:19:26
Intresting - if i turn cont ping off - therefore no traffic over isdn - isdn shuts BRI/Dialer int down and traffic will then go over Serial 0 with no problems and without re-opening isdn call.
I too have had EIGRP working perfectly like this - i think its a weird BGP thing and maybe timers or something???
Configs are as follows:
Centre:
Current configuration : 2178 bytes
!
version 12.3
service timestamps debug uptime
service timestamps log uptime
service password-encryption
!
hostname Tipton
!
boot-start-marker
boot-end-marker
!
username France password 7 123456
no aaa new-model
ip subnet-zero
no ip domain lookup
!
frame-relay switching
isdn switch-type basic-net3
!
interface Loopback0
ip address 172.16.1.10 255.255.255.255
!
interface Loopback1
no ip address
!
interface Ethernet0
description Ethernet Interface to Paris LAN
ip address x.x.x.x 255.255.255.0
!
interface Serial0
no ip address
encapsulation frame-relay IETF
no fair-queue
frame-relay lmi-type ansi
frame-relay intf-type dce
!
interface Serial0.1 point-to-point
ip unnumbered Loopback0
no cdp enable
frame-relay interface-dlci 101
!
interface BRI0
description ISDN Backup to Tipton
ip unnumbered Loopback0
encapsulation ppp
dialer pool-member 1
isdn switch-type basic-net3
ppp authentication chap
ppp multilink
!
interface Dialer1
description Dialer to Tipton
ip unnumbered Loopback0
encapsulation ppp
dialer pool 1
dialer remote-name France
dialer idle-timeout 60
dialer string 532 (internal PBX)
dialer load-threshold 5 either
dialer-group 1
ppp multilink
!
router bgp 100
no synchronization
bgp log-neighbor-changes
network x.x.x.x
neighbor 172.16.1.40 remote-as 400
neighbor 172.16.1.40 ebgp-multihop 255
neighbor 172.16.1.40 update-source Loopback0
no auto-summary
!
ip route 0.0.0.0 0.0.0.0 1.1.1.1
ip route x.x.x.x 255.255.255.0 Dialer1 200
!
access-list 100 permit ip any any
access-list 101 deny tcp any any eq bgp
dialer-list 1 protocol ip list 100
!
!
access-list 100 permit ip any any
access-list 101 deny tcp any any eq bgp - not applied but has been and still the same :-(
access-list 101 permit ip any any
dialer-list 1 protocol ip list 100
Vice Versa for Remote.
ASKER
I realise my description is wrong on the Dialer ;-) - just ignore.
ASKER CERTIFIED SOLUTION
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ASKER
I will try that on Monday when I'm back at work :-/. Think you could be right - changing to a static IP may work or use another loopback.
I cant seem to find any info on BGP with backup ISDN on the net at all?
Anyway - thanks again I'll keep you posted.
I cant seem to find any info on BGP with backup ISDN on the net at all?
Anyway - thanks again I'll keep you posted.
Bare in mind is that BGP is keen of keeping routes out of flapping, therefore, if route selection criteria is matched between 2 links, it will keep the older stable one in place.
You will find the solution here at this thread: https://www.experts-exchange.com/questions/21074656/BGP-outbound-routing-same-length-AS-Paths-round-robin-selection.html
Use MED to sort out what is the preferred outbound interface.
Remember also that the same will apply to the router(s) on the other side of the links (main and backup).
You will find the solution here at this thread: https://www.experts-exchange.com/questions/21074656/BGP-outbound-routing-same-length-AS-Paths-round-robin-selection.html
Use MED to sort out what is the preferred outbound interface.
Remember also that the same will apply to the router(s) on the other side of the links (main and backup).
ASKER
I created another loopback and everything worked fine - just goes to show what a fresh pair of eyes checking over your config can do. Thanks Steve.
Thankyou clesmk for the advice too - although I think this is more for a multihomed scenerio.
Thankyou clesmk for the advice too - although I think this is more for a multihomed scenerio.
Glad I could help. Thanks for the "A" :)
I can't think of any reason why this wouldn't work - I've done it with EIGRP with no trouble.
Just to clarify, the router is doing the dial-up in the event of the Frame Relay failure, but not hanging up when the FR is back?
Now for a few questions :)
When the frame-relay circuit comes back, does the router interface come up properly?
Can you ping the remote frame-relay interface OK?
What does the routing table (show ip route) show as your default route once the frame-relay is back?
If you could post the relevant parts of the config, that would help.
Thanks
Steve