[j-nsp] load balancing in Route reflector scenario

[Robert Raszuk]

Hi Keegan,

>     Nope ... there can be other "producers" of the same route (OSPF,
>     ISIS, STATIC) which will be in the RIB. If not there is always next
>     step - less specific route to be used.
>
> I suppose there's a use for this or the feature wouldn't exist, but why
> would you have a route in the IGP that's not in BGP

no no ... this entire discussion is about the case where the identical 
prefix is in both producers ... for example in OSPF and in eBGP. If it 
is only in one non of this what we are talking here applies.

> but still needs to
> receive traffic from routers running an IGP and BGP but not learning the
> route from the IGP.

It is as said the other way around.

> Why not just import the route(s) into BGP.  It just
> seems like this command may cause unexpected behavior to add features
> that can be configured in a more graceful manner.

Very simple example:

Some destination is reachable over EBGP ... the same route is advertised 
into AS via IBGP. All good. Now for some reason an operator is ordered 
to redirect all traffic going to dst X to go via some screening box.

So on this said ASBR which normally would just switch out the packets, 
NOC guy is inserting a static route into RIB to say all which dst ix X 
go to this box. Then effectively this would cause BGP to stop 
advertising it as the RIB active route is now from static and not BGP.

That's just one of the use case of traffic redirection by control 
plane/routing twick - yet not impacting the BGP operation.

Cheers,
R.