funny ECMP

Ingo Flaschberger if at xip.at
Tue Aug 24 20:36:38 UTC 2010


Dear Li,

>  Sure, but such a configuration did not make much sense.

Why not?
Use CARP and OSPF and you have such a configuration.

>  I read your other email explaining why your system is configured
>  this way but I am still unclear from you text.


Router 1 and Router 2 share 1 Ipadress via VRRP / CARP at interface LAN
Router 1 and Router 2 speak OSPF (routing protocoll) at interface WAN

Router 1 tells those routes to Router 2 and back.

With CARP when the interface LAN at Router 1 ist in state MASTER, there is
the LAN-IP online and also the LAN-Net.

At this moment also Router 2 holds a route to LAN-net via Router 1 WAN 
interface.

Now Router 1 interface LAN goes down.
Router 2  CARP recognize this, and want to install LAN-IP and LAN-net.
-> can not install route as there is still a route from Router 1.


I hoped, that now, as freebsd has multi-route support (as other unix 
really have for a long long time) everything would be easier.

But multipath support of freebsd is in my opinion, in a "experimental" 
state.


Kind regards,
 	Ingo Flaschberger



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