The Routing Over Large Clouds Mailing List Archive by date

[Tony Li <tli@cisco.com>]

   I have some questions about the NHRP-02 (August 25) draft. The
   I have some questions about the NHRP-02 (August 25) draft. The
   document describes the details including packet formats 
   by which a request for binding info
   between a destination IP address and an NBMA next-hop address is
   between a destination IP address and an NBMA next-hop address is
   propagated through the NBMA network and replies are generated.  What I
   propagated through the NBMA network and replies are generated.  What I
   am not clear about is the details of the packet forwarding procedure
   followed by a station that is not a server directly connected to the
   NBMA network.
   NBMA network.

   Section 2 states that when a station S wants to resolve the NBMA
   Section 2 states that when a station S wants to resolve the NBMA
   address corresponding to the IP address of an intended destination D,
   it forms a NHRP request and forwards the request to its NHS (whose
   identity is determined by configuration). It then describes how the
   NHRP request is resolved by forwarding the NHRP request among NHS's as
   necessary, and that this info. is cached by NHSs.  

   What is done with the IP-NBMA address binding sent back to the originating
   What is done with the IP-NBMA address binding sent back to the originating
   station S?  I assume that client stations
   like S also maintain a cache of received NHRP reply bindings.
   Presumably, station S will update its cache with the results of NHRP
   replies. Furthermore, presumably S will consult its cache prior to the
   issuing of a NHRP request (and not issue a request if there is a hit).

Exactly.

   Also when exactly do stations like S register with their NHSs? 
   Also when exactly do stations like S register with their NHSs? 

Either at boot time or statically.

   Since there is a holding time associated with the
   binding, do stations have to periodically re-register? Or do NHS's
   request stations to re-register when the holding time expires?

My understanding is that they should periodically re-register.  As we
My understanding is that they should periodically re-register.  As we
can expect relatively long hold times which are known to the station,
this is very much a background low bandwidth task.

Tony