Changing ECMP weight on OSPF routes with an ingress filter

[Alarig Le Lay]

Hi,

I have a setup with some routers:

 +----------------+ +----------------+ +---------------+
 | close router 1 | | close router 2 | | far router    |
 | 45.91.126.233  | | 45.91.126.236  | | 45.91.126.235 |
 +----------------+ +----------------+ +---------------+
                   \         |        /       |
                    \ +-------------+/  +---------------+
                     \| core router |   | other routers |
		      +-------------+   +---------------+

Each edge router announces a default to my core router, and I have ECMP
to balance the traffic.

bird> show route all 0.0.0.0/0
Table master4:
0.0.0.0/0            unicast [ospf_ipv4 12:15:31.798] I (150/30) [89.234.186.31]
        via 45.91.126.233 on tinc0 weight 1
        via 45.91.126.235 on tinc0 weight 1
        via 45.91.126.236 on tinc0 weight 1
        Type: OSPF univ

I tried to change ecmp_weight on the ospf import filter matching the
router ID, but I have this message: “/etc/bird.conf:81:22 Symbol
`ecmp_weight' is read-only.”

I don’t want to change the weight on the far router as there are other
routers to have their default on 45.91.126.233 and 45.91.126.236.
I can’t change the cost on the link as it’s the same L2 viewed from the
core router.

Is there a simple mean to achieve this or is it a better idea to switch
to BGP?


Thanks,
-- 
Alarig