[c-nsp] Load balancing outbound traffic with BGP

[Hay Kan Sugeng]

imho,

for equal cost use maximum-paths.

http://www.cisco.com/en/US/docs/ios/12_3/iproute/command/reference/ip2_k1g.html#wp1058588


Jeff Chan wrote:
> Hi All,
> Given multiple, roughly equal upstreams (Sprint, ATT, Level3)  
> providing full BGP tables to a small ISP, what's the best way to  
> balance the outbound traffic?  The problem is that all else being  
> equal (path length, local pref, etc.) BGP decides to take the one with  
> the lowest peering IP address.  Given that the upstreams have  
> many/most of the same customers and peers, the peer with the lowest IP  
> address seems to win too often, meaning it does too much outbound  
> compared to the others.
>
> I asked the same question some time ago and the common practice answer  
> seemed to be prefer traffic for some other large networks (UUNet,  
> Qwest, AOL, etc.) over the peers with higher IP address.  Is this  
> still the case?  Seems kind of an ugly hack, but it works.
>
> Are there any other approaches?  How about jumbling up or staggering  
> the local preferences:
>
> ISP S:
>
> customers: localpref 120
> peers:     localpref 110
> others:    localpref 100
>
> ISP A:
>
> customers: localpref 110
> peers:     localpref 100
> others:    localpref  90
>
> ISP L:
>
> customers: localpref 100
> peers:     localpref  90
> others:    localpref  80
>
> Where S has the highest IP address, A next highest, L lowest.  Haven't  
> tried this; just a thought to try to compensate for the IP address  
> decision.
>
> Cheers,
>
> Jeff C.
>
> _______________________________________________
> cisco-nsp mailing list  cisco-nsp at puck.nether.net
> https://puck.nether.net/mailman/listinfo/cisco-nsp
> archive at http://puck.nether.net/pipermail/cisco-nsp/
>
>