[j-nsp] Copy of inet.0

Pedro Roque Marques roque at juniper.net
Fri Oct 29 18:06:23 EDT 2004

John Payne writes:

> Which version?  6.4 gives me:

> [edit] jpayne at lab# show routing-instances

> [edit] jpayne at lab# set routing-instances FOO instance-type
> forwarding

Sorry, you will need to switch the instance type to
virtual-router. Which is the same thing, expect that it can take
interface statements...

> Will instance-import pull out individual routes from a multipath
> setup?  ie if I have multiple active multipath routes to a
> destination, can I use instance-import to grab one of them?  (Based
> on community perhaps?)

Depends on what you are refering to...

There is prefix (route), path (route entry) and next-hop...

i.e.	if you do a show route you will see something like

	    path 1
		 nexthop a, b
	    path 2
	         Inactive due to: something.
	         nexthop c, d

BGP will install multiple paths to the same prefix... IGPs will only
install one path.

instance-import will only pick the active path (path 1 above). This is
how the mecanism is defined... and it serves to avoid the potential
case where you would just be duplicating all received routing updates
between tables.

If you want/need path 2, maybe w/ different attributes, then you have
to explicitly use rib-groups.

Both mecanisms use whatever next-hop the path has (regardless if it
has 1 or more gateways).

You can pick between the multiple next-hops which one is used for
forwarding via the install-next hop policy action on routing-options 
forwarding export policy.

I hope i've not added to the confusion...


More information about the juniper-nsp mailing list