Re: [Idr] Can one Destination Address appear in both Tunnel Encap Attribute and in MP_REACH_NLRI ?

[Robert Raszuk <[e-mail]>]

Hey Srihari,

> The presence of Tunnel Encapsulation attribute in an update that carries
MP_REACH
> attribute indicates the data path destined for prefixes encoded in the
NLRI field of MP_REACH.

My reading of Linda's point was a question regarding the case where for
prefix A NLRI points to
next hop NH_1 but tunnel endpoint says go to NH_2.

Is such update still valid ?

Has tunnel encapsulation attribute power to "overrule" BGP next hop from
MP_REACH ?

When BGP best path runs and validates NH_1 is basic next hop validation
also performed on
NH_2 before considering this path as valid ?

When BGP selects such path as best and installs it to RIB does it install
it with NH_1 or NH_2 ? Note that both next hops may be reachable via local
IGP or even going further could be recursive via yet more BGP routes.

Many thx,
Robert.


If a Destination address is already listed in the MP_RACH_NLRI, is it
> listed again in the Tunnel Encap subTLV (if it can be reached via some
> tunnel, such as VxLAN/GRE/?
>
>
>
> I’m not clear what you mean here. The MP_REACH provides the reachability
> information while the Tunnel Encapsulation Attribute provides the Tunnel
> details (remote-endpoint, encapsulation, etc). The presence of Tunnel
> Encapsulation attribute in an update that carries MP_REACH attribute
> indicates the data path destined for prefixes encoded in the NLRI field of
> MP_REACH.
>
>
>
> Thanks.
>
> srihari…
>