[afnog] BGP routing in multihomed environment

[Eddy Kayihura M.]

Hi Bill,

It appears to me that Europe HUB (AS25228) is doing some AS prepending.
Their path to 3356 might not be their preferred one.
Have you discussed that with them?
If they are the one who configured it that way, I doubt you could 
overload their settings unless they provide some other way of doing so.
This is info is as far as my knowledge goes :-) maybe someone else has a 
better idea.

regards

Eddy


Bill Sangiwa wrote:
> hi!
>
> my schematic network, have BGP (plain vanilla as below) to both UPstream 
> providers
>
> ISP (AS36959) <-- RX ONLY-- Europe HUB (AS25228)--- NET
>
>                      ^
>                       ---TX/RX ----> Europe HUB(AS5377) ---- NET
>
>
> from looking glass (router ID is 195.66.225.241), is see the routes via 
> AS25228 are repeated
>
> <my network>  195.66.226.77    0   0 3356 25228 25228 25228 36959 i
>
> what could be wrong on the setup. certainly that route is not favoured and how 
> to i make it more favoured? will the use of non-exist-map and the 
> advertise-map keywords would help to overcome the problem? anything am 
> missing??
>
> router bgp 36959
>  no synchronization
>  bgp log-neighbor-changes
>  bgp dampening
>  ! 
>  network 196.12.12.0 mask 255.255.252.0
>  <.... some network command removed...>
>  !
>  neighbor 193.219.192.33 remote-as 5377
>  neighbor 193.219.192.33 description <UPSTREAM A>
>  neighbor 193.219.192.33 ebgp-multihop 255
>  neighbor 193.219.192.33 update-source Loopback0
>  neighbor 193.219.192.33 version 4
>  neighbor 193.219.192.33 timers 60 1000
>  neighbor 193.219.192.33 send-community
>  neighbor 193.219.192.33 soft-reconfiguration inbound
>  neighbor 193.219.192.33 prefix-list receive in
>  neighbor 193.219.192.33 prefix-list announce out
>  !
>  neighbor 217.194.158.230 remote-as 25228
>  neighbor 217.194.158.230 description to  <UPSTREAM B>
>  neighbor 217.194.158.230 password <too secure to release>
>  neighbor 217.194.158.230 ebgp-multihop 255
>  neighbor 217.194.158.230 update-source Loopback0
>  neighbor 217.194.158.230 version 4
>  neighbor 217.194.158.230 send-community
>  neighbor 217.194.158.230 soft-reconfiguration inbound
>  neighbor 217.194.158.230 prefix-list receive in
>  neighbor 217.194.158.230 prefix-list announce out
>  !
>  neighbor 217.194.158.231 remote-as 25228
>  neighbor 217.194.158.231 description to <UPSTREAM B backup>
>  neighbor 217.194.158.231 password <too secure to release>
>  neighbor 217.194.158.231 ebgp-multihop 255
>  neighbor 217.194.158.231 update-source Loopback1
>  neighbor 217.194.158.231 version 4
>  neighbor 217.194.158.231 send-community
>  neighbor 217.194.158.231 soft-reconfiguration inbound
>  neighbor 217.194.158.231 prefix-list receive in
>  neighbor 217.194.158.231 prefix-list announce out
>  !
>  no auto-summary
> !
>
>