Many default network defined on core switch

[Rajeev Ranjan]

Hi Friends,

Is it possible to define 4 or many default network.

ip route 0.0.0.0 0.0.0.0 x.x.x.x

ip route 0.0.0.0 0.0.0.0 y.y.y.y

ip route 0.0.0.0 0.0.0.0 z.z.z.z

ip route 0.0.0.0 0.0.0.0 a.a.a.a,

where x.x.x.x and a.a.a.a are in same vlan

and y.y.y.y and z.z.z.z are in the same vlan.

I see this configuration on my core switch and i dont understand why 4 default route is configured.

Kindly explian me.

[Giuseppe Larosa · Accepted solution]

Hello Rajeev,

you see 4 different IP next-hops for the default route and this is a legitimate configuration.

It is correct configuration if all these 4 next hops are alive and lead to appropriate devices.

The router will perform flow based load balancing using an EXOR of last two significant bits of IP Source address and IP destination address of the packet to choice one of  the 4 available paths for all destinations that  have no explicit match in the IP routing table.

So all packets with the same IP SA and IP DA will use the same outgoing path avoiding out of order problems

Hope to help

Giuseppe