RE: [pacnog] Multihoming Problem

["Alo Anesi" <Alo.Anesi@bluesky.as>]

The config is pretty straightforward:

Router peering with Primary AS25625:

router bgp 23657
 no synchronization
 bgp log-neighbor-changes
 network 202.70.112.0 mask 255.255.240.0
 neighbor 202.70.114.101 remote-as 25625
 neighbor 202.70.114.101 description Peering with Upstream IP Access
 neighbor 202.70.114.101 soft-reconfiguration inbound
 neighbor 202.70.114.101 prefix-list DEFAULT-ONLY in
 neighbor 202.70.114.101 prefix-list BSKY-AGGREGATE out
 neighbor 202.70.114.101 route-map ALLOW-DEFAULT-IN in
 neighbor 202.70.114.101 route-map BSKY-OUT out

ip prefix-list BSKY-AGGREGATE seq 5 permit 202.70.112.0/20
!
ip prefix-list DEFAULT seq 15 permit 0.0.0.0/0

route-map ALLOW-DEFAULT-IN permit 10
 match ip address prefix-list DEFAULT-ONLY
 set local-preference 220

route-map BSKY-OUT permit 10
 match ip address prefix-list BSKY-AGGREGATE

Router peering with Secondary AS30362:

router bgp 23657
 no synchronization
 bgp log-neighbor-changes
 network 202.70.112.0 mask 255.255.240.0
 neighbor HPT peer-group
 neighbor HPT remote-as 30362
 neighbor HPT next-hop-self
 neighbor HPT remove-private-AS
 neighbor HPT version 4
 neighbor HPT soft-reconfiguration inbound
 neighbor HPT route-map HPT_NET_IN in
 neighbor HPT route-map HPT_NET_OUT out
 neighbor x.x.x.x peer-group HPT
 neighbor x.x.x.x ebgp-multihop 3
 neighbor x.x.x.x peer-group HPT
 neighbor x.x.x.x ebgp-multihop 3

route-map HPT_NET_OUT permit 10
 match ip address prefix-list US_MAINLAND_TRANSIT_OUT
 set as-path prepend 23657 23657 23657 23657 23657 23657 23657 23657 23657 23657

ip prefix-list US_MAINLAND_TRANSIT_OUT seq 5 permit 202.70.112.0/20

That's it in a nutshell. As for mirroring, can you span/mirror a serial port to an Ethernet port on a 7206VXR?

-----Original Message-----
From: pacnog-bounces@pacnog.org [mailto:pacnog-bounces@pacnog.org] On Behalf Of Scott Weeks
Sent: Wednesday, February 07, 2007 12:29 PM
To: pacnog@pacnog.org
Subject: Re: [pacnog] Multihoming Problem




Hello,

Looking at one of our our BGP routers (AS36149) I see you through AS25625.  Have you tried mirroring the traffic to see what it is and where it's going?  Perhaps you could remove proprietary parts of your config and let us see it?

scott


--- Alo.Anesi@bluesky.as wrote:

I seem to be having some problems with my multihoming arrangement. Our
current setup is to advertise our /20 on both of our upstream providers:
AS25625 is the primary and AS30362 is the secondary.

I have a 10x as-path prepend for AS30362 since we only have a single T1
with that upstream. There is no as-path prepend on our primary.

What I'm trying to do is have all traffic flow through our primary and
only go through the secondary when the primary link fails. What actually
happens is that our secondary link becomes saturated and our primary
link only runs at about 50% capacity even with the maximum as-path
prepend.

I've checked several looking glass routers and our primary link seems to
be the best path, but I can't account for such a large amount of traffic
on our secondary.

Any suggestions?

P.S. We are AS23657
























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