[c-nsp] cef load-sharing and recursive routing

[Xavier Nicollet]

Maybe this option could help:

http://www.cisco.com/c/en/us/td/docs/ios/ipswitch/command/reference/isw_book/isw_c1.html#wp1030372

However I have never met this. Anyone has ever used this on 7600 platform ?

Regards,


2015-01-22 10:59 GMT+01:00 Xavier Nicollet <xnicollet at gmail.com>:

> Hi,
>
> I have an issue with cef load-sharing used as a way to load-balance
> servers.
>
> Cisco CEF tends to simplify some path, as in this exemple:
>
> ip route 10.30.30.30/32 web1 (directly attached)
> ip route 10.30.30.30/32 web2 (remote site)
> ip route 10.30.30.30/32 web3 (remote site)
>
> We would like to have each server with a weight of 1, having one third of
> the traffic.
>
> However, CEF will count remote site as just one destination, leading to:
>
> #show ip cef 10.30.30.30 internal
> 10.30.30.30/32, epoch 8, RIB[S], refcount 6, per-destination sharing
> /SNIP/
>   output chain:
>     loadinfo 1A4EDAB4, per-session, 2 choices, flags 0083, 5 locks
>     flags: Per-session, for-rx-IPv4, 2buckets
>     2 hash buckets
>       < 0 > IP adj out of Vlan9, addr 10.14.9.1
>       < 1 > IP adj out of TenGigabitEthernet6/4, addr /SNIP/
>
> Has you see all the destination that lead to path Te6/4 will be accounted
> for just one path.
> This is very annoying since we have the same routes configured on remote
> site, which can lead to routing loops for some
> @IP src / @IP dst couples.
>
> Is there a way to force the router to put exactly the same weight for each
> entry, without any path optimisation ?
>
> We are using cisco 7600 with RSP720. To my knowledge, openflow and such
> are not supported on this platform, right ?
>
> Thank you for your help,
>
> --
> Xavier Nicollet
>



-- 
Xavier Nicollet