rfc2297.txt

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Network Working Group                                    P. Newman, Nokia
Request for Comments: 2297                             W. Edwards, Sprint
Updates: 1987                                            R. Hinden, Nokia
Category: Informational                                 E. Hoffman, Nokia
                                                            F. Ching Liaw
                                                           T. Lyon, Nokia
                                                   G. Minshall, Fiberlane
                                                               March 1998


       Ipsilon's General Switch Management Protocol Specification
                              Version 2.0

Status of this Memo

   This memo provides information for the Internet community.  It does
   not specify an Internet standard of any kind.  Distribution of this
   memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (1998).  All Rights Reserved.


Abstract

   This memo specifies enhancements to the  General Switch Management
   Protocol (GSMP) [RFC1987]. The major enhancement is the addition of
   Quality of Service (QoS) messages. Other improvements have been made
   to the protocol resulting from operational experience. GSMP is a
   general purpose protocol to control an ATM switch. It allows a
   controller to establish and release connections across the switch;
   add and delete leaves on a multicast connection; manage switch ports;
   request configuration information; and request statistics.

















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Table of Contents

   1. Introduction....................................................3

   2. GSMP Packet Encapsulation.......................................4
      2.1 ATM Encapsulation...........................................4
      2.2 Ethernet Encapsulation......................................6

   3. Common Definitions and Procedures...............................7
      3.1 GSMP Packet Format..........................................8
      3.2 Failure Response Messages..................................11

   4. Connection Management Messages.................................16
      4.1 Add Branch Message.........................................21
      4.2 Delete Tree Message........................................23
      4.3 Verify Tree Message........................................24
      4.4 Delete All Message.........................................24
      4.5 Delete Branches Message....................................25
      4.6 Move Branch Message........................................27

   5. Port Management Messages.......................................29
      5.1 Port Management Message....................................29
      5.2 Label Range Message........................................34

   6. State and Statistics Messages..................................37
      6.1 Connection Activity Message................................38
      6.2 Statistics Messages........................................40
          6.2.1 Port Statistics Message..............................44
          6.2.2 Connection Statistics Message........................44
          6.2.3 QoS Class Statistics Message.........................44
      6.3 Report Connection State Message............................45

   7. Configuration Messages.........................................49
      7.1 Switch Configuration Message...............................50
      7.2 Port Configuration Message.................................51
      7.3 All Ports Configuration Message............................57

   8. Event Messages.................................................59
      8.1 Port Up Message............................................60
      8.2 Port Down Message..........................................60
      8.3 Invalid VPI/VCI Message....................................61
      8.4 New Port Message...........................................61
      8.5 Dead Port Message..........................................61

   9. Quality of Service Messages....................................61
      9.1 Abstract Switch Model......................................62
      9.2 QoS Configuration Message..................................66
      9.3 Scheduler Establishment Message............................74



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      9.4 QoS Class Establishment Message............................78
      9.5 QoS Release Message........................................85
      9.6 QoS Connection Management Message..........................86
      9.7 QoS Failure Response Codes.................................97

   10. Adjacency Protocol............................................97
      10.1 Packet Format.............................................98
      10.2 Procedure.................................................101
      10.3 Loss of Synchronization...................................103

   11. Summary of Failure Response Codes.............................104

   12. Summary of Message Set........................................105

   References........................................................107
   Security Considerations...........................................107
   Authors' Addresses................................................107
   Full Copyright Statement..........................................109



1. Introduction

   The General Switch Management Protocol (GSMP), is a general purpose
   protocol to control an ATM switch. GSMP allows a controller to
   establish and release connections across the switch; add and delete
   leaves on a multicast connection; manage switch ports; request
   configuration information; and request statistics. It also allows the
   switch to inform the controller of asynchronous events such as a link
   going down. GSMP runs across an ATM link connecting the controller to
   the switch, on a control connection (virtual channel) established at
   initialization. GSMP operation across an Ethernet link is also
   specified. The GSMP protocol is asymmetric, the controller being the
   master and the switch being the slave. Multiple switches may be
   controlled by a single controller using multiple instantiations of
   the protocol over separate control connections.

   A switch is assumed to contain multiple "ports". Each port is a
   combination of one "input port" and one "output port". Some GSMP
   requests refer to the port as a whole whereas other requests are
   specific to the input port or the output port.  ATM cells arrive at
   the switch from an external communication link on incoming virtual
   paths or virtual channels at an input port. ATM cells depart from the
   switch to an external communication link on outgoing virtual paths or
   virtual channels from an output port. Virtual paths on a port or link
   are referenced by their virtual path identifier (VPI). Virtual
   channels on a port or link are referenced by their virtual path and
   virtual channel identifiers (VPI/VCI).



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   A virtual channel connection across a switch is formed by connecting
   an incoming virtual channel to one or more outgoing virtual channels.
   Virtual channel connections are referenced by the input port on which
   they arrive and the virtual path and virtual channel identifiers
   (VPI/VCI) of their incoming virtual channel. A virtual path
   connection across a switch is formed by connecting an incoming
   virtual path to one or more outgoing virtual paths. Virtual path
   connections are referenced by the input port on which they arrive and
   their virtual path identifier (VPI).  In a virtual path connection
   the value of the VCI in each cell on that, connection is not used by
   the switch and remains unchanged by the switch.

   GSMP supports point-to-point and point-to-multipoint connections. A
   multipoint-to-point connection is specified by establishing multiple
   point-to-point connections each of them specifying the same output
   branch. A multipoint-to-multipoint connection is specified by
   establishing multiple point-to-multipoint trees each of them
   specifying the same output branches.

   In general a virtual channel is established with a certain quality of
   service (QoS). A rich set of QoS messages is introduced in this
   version of the protocol. However, implementation or operation of GSMP
   without any of the messages defined in Section 9, "Quality of service
   messages," is permitted.  In this case each virtual channel
   connection or virtual path connection may be assigned a priority when
   it is established. It may be assumed that for virtual connections
   that share the same output port, an ATM cell on a connection with a
   higher priority is much more likely to exit the switch before an ATM
   cell on a connection with a lower priority if they are both in the
   switch at the same time. The number of priorities that each port of
   the switch supports may be obtained from the port configuration
   message.

   GSMP contains an adjacency protocol. The adjacency protocol is used
   to synchronize state across the link, to negotiate which version of
   the GSMP protocol to use, to discover the identity of the entity at
   the other end of a link, and to detect when it changes.


2. GSMP Packet Encapsulation

2.1 ATM Encapsulation

   GSMP packets are variable length and for an ATM data link layer they
   are encapsulated directly in an AAL-5 CPCS-PDU [I.363] with an
   LLC/SNAP header as illustrated:





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    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |               LLC (0xAA-AA-03)                |               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+               +
   |                   SNAP (0x00-00-00-88-0C)                     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   ~                         GSMP Message                          ~
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                     Pad (0 - 47 octets)                       |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   +               AAL-5 CPCS-PDU Trailer (8 octets)               +
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   (The convention in the documentation of Internet Protocols [RFC1700]
   is to express numbers in decimal. Numbers in hexadecimal format are
   specified by prefacing them with the characters "0x".  Data is
   pictured in "big-endian" order. That is, fields are described left to
   right, with the most significant octet on the left and the least
   significant octet on the right. Whenever a diagram shows a group of
   octets, the order of transmission of those octets is the normal order
   in which they are read in English. Whenever an octet represents a
   numeric quantity the left most bit in the diagram is the high order
   or most significant bit. That is, the bit labeled 0 is the most
   significant bit. Similarly, whenever a multi-octet field represents a
   numeric quantity the left most bit of the whole field is the most
   significant bit. When a multi-octet quantity is transmitted, the most
   significant octet is transmitted first. This is the same coding
   convention as is used in the ATM layer [I.361] and AAL-5 [I.363].)

   The LLC/SNAP header contains the octets: 0xAA 0xAA 0x03 0x00 0x00
   0x00 0x88 0x0C. (0x880C is the assigned Ethertype for GSMP.)

   The maximum transmission unit (MTU) of the GSMP Message field is 1492
   octets.

   The virtual channel over which a GSMP session is established between
   a controller and the switch it is controlling is called the GSMP
   control channel.  The default VPI and VCI of the GSMP control channel
   for LLC/SNAP encapsulated GSMP messages on an ATM data link layer is:

      VPI = 0