Re: FW: [mpls-linux-general] Problems in configuring multiple LSPs on multiple physical paths for the same destination

[James R. L. <jl...@mi...>]

On Wed, Jul 21, 2004 at 03:59:47PM +0300, Muhammad R. Sami wrote:
> I used the following command on the ingress
> 
> ip route add 192.168.11.2/32 nexthop via 192.168.12.2 spec_nh 0x8847 0x2 \  
> nexthop via 192.168.15.2 spec_nh 0x8847 0x3
> 
> and got the response as
> 
> RTNETLINK answers: invalid argument

We've already went over this, but to re-iterate:

spec_nh is just a tag on a nexthop.  Therefore it will not make a
nexthop unique.  If you remove the spc_nh tag from the command you'll
see why 'ip' is complaining, your telling it to add the exact same nexthop
twice.  You cannot do that.  You must have, at the very minimum, a different
nexthop IP address.

This is completly orthoganl to your problem though.  You do not need to add
the multiple nexthops on 'A'.  In my sample config I only had one nexthop
specified for the route to 2.2.2.2.  The process of assigning packets to the
different LSPs is done by the MPLS layer NOT the IPv4 layer.

> However a similar command executes without any trouble on the egress. When I
> run the following command on the ingress
> 
> ip route add 192.168.11.2/32 via 192.168.12.2 spec_nh 0x8847 0x2
> 
> it executes without trouble showing that "ip route" command is working. Can
> you kindly tell me the possible reason for this.
> 

-- 
James R. Leu
jl...@mi...