Hi Tonnie, For me to fully understand your topology, i have a couple of questions to ask - please see inline. On 12/8/10 6:24 PM, tonnie@swiftkenya.com wrote:
Hi Skunks
I?m trying to configure auto-failover between KDN and Safcom links, with KDN being the primary. My router config is as below
ok
BGP Config
router bgp 65200 no synchronization bgp log-neighbor-changes network 132.147.160.0 mask 255.255.255.0
This is fine.
network 172.16.0.0 mask 255.255.255.0 network 192.168.7.0
not necessary unless you want to advertise them to other peers internally.
timers bgp 30 45 neighbor 172.30.6.181 remote-as 37061 neighbor 172.30.6.181 ebgp-multihop 3
Why ebgp multihop?
neighbor 172.30.6.181 update-source FastEthernet0/0/0 neighbor 172.30.6.181 weight 100 neighbor 172.30.6.181 prefix-list INSECTA-ROUTE out neighbor 172.220.70.33 remote-as 65160 neighbor 172.220.70.33 ebgp-multihop 3
again why ebgp-multi-hop?
neighbor 172.220.70.33 update-source GigabitEthernet0/1 neighbor 172.220.70.33 weight 1000 neighbor 172.220.70.33 prefix-list INSECTA-ROUTE out
Could you show what the prefix list looks like - am trying to determine what prefix is being announced to your upstreams.
no auto-summary !
When I shut down KDN interface, Safcom link picks up traffic, but when I bring up the KDN interface, it doesn?t come as primary until I shut down Safaricom. I have given KDN link the required weight.
When you mean primary is it for ingress or egress traffic. The Weight attribute on BGP only affects egress traffic and not ingress. There are other attributes that you need to use for the ingress traffic. I would do a different thing to try and achieve this instead of using weights. I would assume you are receiving a default route from both KDN and Swift. I would set the a high local pref (say 200) for the prefix learned via KDN. This way by default all traffic would exit via KDN link. It also means that you have to ask KDN and Safaricom to send you the default route. (this is how to set the egress primary link). For the KDN link to be your primary inbound considering that you have a /24 and a private ASN, i would recommend that Safaricom should set an AS-path prepend or use communities when announcing your prefixes to their upstream not to be the preferred path. Alternatively, please get your own ASN number and start originating your prefixes - that way you have full control over your routing policies. I hope that helps. Michuki.