RFC 3186 (rfc3186) - Page 2 of 14

MAPOS/PPP Tunneling mode

RFC 3186                MAPOS/PPP Tunneling mode           December 2001


      a) MAPOS frame header (version 1)
         +-----------+-----------+-----------+-----------+
         | Address   | Control   | Protocol              |
         |  8 bits   | fixed,0x03| 16 bits               |
         +-----------+-----------+-----------+-----------+

      b) MAPOS frame header (MAPOS 16)
         +-----------+-----------+-----------+-----------+
         | Address               | Protocol              |
         |   16bits              | 16 bits               |
         +-----------+-----------+-----------+-----------+

      c) PPP frame header
         +-----------+-----------+-----------+-----------+
         | Address   | Control   | Protocol              |
         | fixed,0xFF| fixed,0x03| 16 bits               |
         +-----------+-----------+-----------+-----------+

      Figure 1. Header similarity of MAPOS frame and POS frame

   This means that a MAPOS network can easily carry POS frames with no
   additional header overhead by rewriting only 1 or 2 octets.  PPP
   tunneling configuration over MAPOS networks (MAPOS/PPP tunneling
   mode) provides for efficient L2 multiplexing by which users can share
   the cost of high speed long-haul links.

   This document specifies MAPOS/PPP tunneling mode.  In this mode, a
   MAPOS network provides a point-to-point link for those who intend to
   connect POS equipment.  Such link is established within a MAPOS
   switch, or between a pair of MAPOS switches that converts between POS
   header and MAPOS header for each L2 frame.

   Chapter 2 describes the specification in two parts.  First part is
   user network interface (UNI) specification and the second part is
   operation, administration, management and provisioning (OAM&P)
   description.  Other issues such as congestion avoidance, end-to-end
   fairness control are out of scope of this document.

   Implementation issues are discussed in Chapter 3.  Security
   considerations are noted in Chapter 4.











Shimizu, et al.              Informational