[c-nsp] route-target import on non-leaking PEs

[Phil Mayers]

On 13/12/12 14:15, Jason Lixfeld wrote:
>
> On 2012-12-13, at 4:29 AM, Adam Vitkovsky <adam.vitkovsky at swan.sk> wrote:
>
>> Using common RD in a vrf is asking for trouble if route-reflection is used.
>>
>> Let's say you have two PEs advertising default for vrf inet -if you use RRs
>> to spread the routes throughout the backbone -RRs will only advertise one
>> (best path)default route to all PEs.
>> Now with unique RD per PE RRs will consider default form each PE as a unique
>> route sending both to all PEs.
>> Than you are ready for fast convergence.
>> adam
>
> Hold on, are you saying that within a single VRF, you can actually use more than one RD?

Yes. In fact, that's *required* if you want to do multi-path.

route target controls what gets "into" a VRF. RD is just a unique value 
that prefixes the route. It can be completely different.

FWIW we use the convention of:

xxx:N

...where N is the last octet of the routers loopback, so the RD is 
different on each router.

There are differing opinions about the wisdom of this strategy - see 
here, for example:

http://blog.ioshints.info/2012/07/bgp-route-replication-in-mplsvpn-pe.html