RFC 2701 (rfc2701) - Page 2 of 9

Nortel Networks Multi-link Multi-node PPP Bundle Discovery Protocol

RFC 2701                          MMP                     September 1999


   RAS in a POP and a secondary connection is established to another.
   This may occur because the first RAS has no available modems, or
   because incoming calls are assigned to ports in a round-robin
   fashion, for example, and the second call is simply assigned to
   another RAS.

   The solution to this problem is to provide a mechanism by which a RAS
   can determine if a Multi-link PPP connection is a primary or
   secondary and, if a secondary, where the Bundle Head (the process
   within a RAS which reassembles the PPP fragments transmitted over the
   primary and secondary links) resides.  If the Bundle Head resides on
   a different RAS, a protocol must be used to transfer the PPP
   fragments to the RAS containing the Bundle Head so that the PPP frame
   can be reassembled.

   Section 2 of this document specifies the Discovery Mechanism.
   Section 3 specifies the Transfer Protocol.  Section 4 specifies the
   configuration parameters needed for the Discovery Protocol.

2.  Bundle Head Discovery Mechanism

   When a user dials into a RAS and negotiates Multi-link PPP (MP)
   during the Link Control Protocol (LCP) phase, the RAS must determine
   which one of the following three cases exists:

   1- This is the primary (first) link of the MP connection.  In this
      case, the RAS should create the Bundle Head.

   2- This is a secondary link of the MP connection and the Bundle Head
      resides on this RAS.  In this case, the RAS should add the link to
      the Bundle (standard MP).

   3- This is a secondary link of the MP connection and the Bundle Head
      resides on a different RAS.  In this case, the RAS should
      establish a path (see section 3) to the RAS that has the Bundle
      Head, and use that path to transfer MP fragments.

   In operation, a RAS will make the determination for case 2 first
   (because it is the easiest and requires no communication with other
   RASes.  If the Bundle Head is not local, the Discovery Protocol is
   used to determine where the Bundle Head is, if it exists at all.










Malkin                       Informational