[c-nsp] Sup720-3BXL load balancing re-visited

[Everton da Silva Marques]

On Fri, Apr 28, 2006 at 10:38:39AM +0000, Kristofer Sigurdsson wrote:
>
(...)
> We cleared all BGP peers on the 7600, now we have almost
> equal load balancing (we've found that we really can't get
> equal load balancing on the 7600, it's more like 1/3
> vs. 2/3, but it's better than all going one way and
> nothing the other!).
>
> Now, my opinion is that this is a problem with load
> balancing in the 7600.  We already have "mls ip cef
> load-sharing simple", which was supposed to solve this
> problem, at least for MPLS tagged routes.  Any other
> ideas?

As I understand:

1) PFC won't load-balance per-packet.
2) PFC can load-balance per-flow. "Per-flow" means
   packets are mapped to an output interface thru
   a hashing function applied to (src_ip, L4_src_port,
   dst_ip, L4_dst_port).
2.1) Per-flow load-balancing can include L4 ports
     for non-mpls-tagged IPv4 packets.
2.2) Per-flow load-balancing won't consider
     L4 ports for mpls-tagged packets.
     It's restricted to src+dst IP addresses.

See this thread:

http://puck.nether.net/pipermail/cisco-nsp/2005-December/026955.html

If anyone has a better picture, please share it. :-)