[pim] Secondary ip address in transit network

["iamredheart22 ." <[e-mail]>]

Hello,

        I have some doubt about PIM on secondary ip address in transit
network. Please refer the topology shown below.


Source(10.10.10.1)-----------------sw1---------------------------sw2------------Rcv

         RFC 4601 mentions the following points.

     "*4.3.4 <https://tools.ietf.org/html/rfc4601#section-4.3.4>Maintaining
Secondary Address List*

*
   Communication of a router's interface secondary addresses to its PIM
   neighbors is necessary to provide the neighbors with a mechanism for
   mapping next_hop information obtained through their MRIB to a primary
   address that can be used as a destination for Join/Prune messages."*



*          Then RFC also talks about the macros mentioned below..*





*     neighbor RPF'(*,G) {
         if ( I_Am_Assert_Loser(*, G, RPF_interface(RP(G))) ) {
              return AssertWinner(*, G, RPF_interface(RP(G)) )
         } else {
              return NBR( RPF_interface(RP(G)), MRIB.next_hop( RP(G) ) )
         }
     }   "The function MRIB.next_hop( S ) returns an address of the next-hop
   PIM neighbor toward the host S, as indicated by the current MRIB.  If
   S is directly adjacent, then MRIB.next_hop( S ) returns NULL.  At the
   RP for G, MRIB.next_hop( RP(G)) returns NULL."
   "The function NBR( I, A ) uses information gathered through PIM Hello
   messages to map the IP address A of a directly connected PIM neighbor
   router on interface I to the primary IP address of the same router
   (Section 4.3.4
<https://tools.ietf.org/html/rfc4601#section-4.3.4>).  The primary IP
address of a neighbor is the address
   that it uses as the source of its PIM Hello messages*."

    What I understand from this is that MRIB.next_hop(S) can return a
secondary ip address
    as a nexthop which then will pass through NBR macro which returns
the primary
    address associated with this secondary address. This primary
address is then used
    as the final nexthop neighbor.


    My question is that in a transit network by what configuration I
    can achieve a scenario so that nexhop(10.10.10.1) on sw2 returns a
    nexthop address which is configured as a secondary address on sw1?

    Can someone please help?

Thanks,

Indranil