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Network Working Group                                           A. DoriaRequest for Comments: 3294                Lulea University of TechnologyCategory: Informational                                       K. Sundell                                                         Nortel Networks                                                               June 2002General Switch Management Protocol (GSMP) ApplicabilityStatus 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 (2002).  All Rights Reserved.Abstract   This memo provides an overview of the GSMP (General Switch Management   Protocol) and includes information relating to its deployment in a IP   network in an MPLS environment.  It does not discuss deployment in an   ATM (Asynchronous Transfer Mode) network or in a raw ethernet   configuration.1. Overview   The General Switch Management Protocol (GSMP) has been available to   the IETF community for several years now as informational RFCs.  Both   GSMPv1.1 (released in March 1996 asRFC 1987 [2]) and GSMPv2.0   (released in August 1998 asRFC 2297 [3]) are available.  Several   vendors have implemented GSMPv1.1.   In V1.1 and V2 GSMP was intended only for use with ATM switches.   During the course of the last two years, the GSMP working group has   decided to expand the purview of GSMP to the point where it can be   used to control a number of different kinds of switch and can thus   live up to what its name indicates; a general switch management   protocol.  To do this, commands and arguments needed to be   generalised and sections needed to be added, discussing the manner in   which the generalised protocol could be applied to specific kinds of   switches and port types.  In short, the protocol has gone through   major changes in the last 24 months.Doria & Sundell              Informational                      [Page 1]

RFC 3294                   GSMP Applicability                  June 2002   GSMP provides an interface that can be used to separate the data   forwarder from the routing and other control plane protocols such as   LDP.  As such it allows service providers to move away from   monolithic systems that bundle the control plane and the data plane   into a single tightly coupled system - usually in a single chassis.   Separating the control components from the forwarding components and   using GSMP for switch management, enables service providers to create   multi-service systems composed of various vendors equipment.  It also   allows for a more dynamic means of adding services to their networks.   The IETF GSMP working group was established in the routing area   because GSMP was being seen as an optional part of the MPLS solution.   In a MPLS system, it is possible to run the routing protocols and   label distribution protocols on one system while passing data across   a generic switch, e.g., an ATM switch.  GSMP provides the switch   resource management mechanism needed in such a scenario.   GSMP has also been selected by the Multiservice Switching Forum (MSF)   as its protocol of choice for the Switch Control Interface identified   in their architecture.  The MSF is an industry forum which, among its   activities establishes their member's requirements and then works   with the appropriate standards bodies to foster their goals.  In the   case of GSMP, the MSF presented the IETF GSMP Working Group with a   set of requirements for GSMP.  The working group has made a   determined effort to comply with those requirements in its   specifications.2. GSMP V3 Document Set   The current version of GSMP is documented in 3 documents:   -  GSMP: General Switch Management protocol V3 [5]   -  GSMP-ENCAPS: General Switch Management Protocol (GSMP) Packet      Encapsulations for Asynchronous Transfer Mode (ATM), Ethernet and      Transmission Control Protocol (TCP) [4]   -  GSMP-MIB: Definitions of Managed Objects for the General Switch      Management Protocol [1]3. General Description   The General Switch Management Protocol V3 (GSMPv3) [5], is a general      purpose protocol to control a label switch.  GSMP allows a      controller to establish and release connections across the switch;      add and delete leaves on a multicast connection; reserve      resources; manage switch ports; request configuration information;      and request statistics.  It also allows the switch to inform theDoria & Sundell              Informational                      [Page 2]

RFC 3294                   GSMP Applicability                  June 2002      controller of asynchronous events such as a link going down.  The      GSMPv3 protocol is asymmetric, the controller being the master and      the switch being the slave.   A physical switch can be partitioned into many virtual switches.      GSMPv3 does not provide support for defining switch partitions.      GSMPv3 treats a virtual switch as if it were a physical switch.   GSMPv3 may be transported in three ways:      -  GSMPv3 operation across an IP network is specified.      -  GSMPv3 operation across an ATM virtual channel is specified.      -  GSMPv3 operation across an Ethernet link is specified.   Other encapsulations are possible, but have not been defined.   Encapsulations are defined in [4].   A label switch is a frame or cell switch that supports connection      oriented switching using the exact match forwarding algorithm      based on labels attached to incoming cells or frames.   A label switch may support multiple label types.  However, each      switch port can support only one label type.  The label type      supported by a given port is indicated in a port configuration      message.  Connections may be established between ports supporting      different label types using the adaptation methods.  GSMPv3      supports TLV labels similar to those defined in MPLS.  Examples of      labels which are defined include ATM, Frame Relay, DS1, DS3, E1,      E3, MPLS Generic Labels and MPLS FECs.   A connection across a switch is formed by connecting an incoming      labelled channel to one or more outgoing labelled channels.      Connections are generally referenced by the input port on which      they arrive and the label values of their incoming labelled      channel.  In some messages, connections are referenced by the      output port.   GSMPv3 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 which specifies the      same output label.  A multipoint-to-multipoint connection is      specified by establishing multiple point-to-multipoint connections      each of which specifies a different input label with the same      output labels.Doria & Sundell              Informational                      [Page 3]

RFC 3294                   GSMP Applicability                  June 2002   In general a connection is established with a certain quality of      service (QoS).  GSMPv3 includes a default QoS Configuration and      additionally allows the negotiation of alternative, optional QoS      configurations.  The default QoS Configuration includes three QoS      Models: a default service model, a simple priority model and a QoS      profile model.  GSMPv3 also supports the reservation of resources      when the labels are not yet known.  This ability can be used in      support of MPLS.   GSMP contains an adjacency protocol.  The adjacency protocol is used      to synchronise states 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.3.1 Switch Partitioning   In GSMPv3 switch partitioning is static and occurs prior to running   the protocol.  The partitions of a physical switch are isolated from   each other by the implementation and the controller assumes that the   resources allocated to a partition are at all times available to that   partition and only that partition.  A partition appears to its   controller as a physical label switch.  The resources allocated to a   partition appear to the controller as if they were the actual   physical resources of a physical switch.  For example if the   bandwidth of a port is divided among several partitions, each   partition would appear to the controller to have its own independent   port with its fixed set of resources.   GSMPv3 controls a partitioned switch through the use of a partition   identifier that is carried in every GSMPv3 message.  Each partition   has a one-to-one control relationship with its own logical controller   entity (which in the remainder of the document is referred to simply   as a controller) and GSMPv3 independently maintains adjacency between   each controller-partition pair.3.2 Switch and controller interactions   Multiple switches may be controlled by a single controller using   multiple instantiations of the protocol over separate control   connections.   Alternatively, multiple controllers can control a single switch.   Each controller would establish a control connection to the switch   using the adjacency protocol.  The adjacency mechanism maintains a   state table indicating the control connections that are being   maintained by the same partition.  The switch provides information to   the controller group about the number and identity of the attached   controllers.  It does nothing, however, to co-ordinate the activitiesDoria & Sundell              Informational                      [Page 4]

RFC 3294                   GSMP Applicability                  June 2002   of the controllers, and will execute all commands as they are   received.  It is the controller group's responsibility to co-ordinate   its use of the switch.  This mechanism is most commonly used for   controller redundancy and load sharing.  Definition of the mechanism   by which controllers use to co-ordinate their control is not within   GSMPv3's scope.3.3 Service support   All GSMPv3 switches support the default QoS Configuration.  A GSMPv3   switch may additionally support one or more alternative QoS   Configurations.  GSMP includes a negotiation mechanism that allows a   controller to select from the QoS configurations that a switch   supports.   The default QoS Configuration includes three models:      The Service Model is based on service definitions found external         to GSMP such as in CR-LDP, Integrated Services or ATM Service         Categories.  Each connection is assigned a specific service         that defines the handling of the connection by the switch.         Additionally, traffic parameters and traffic controls may be         assigned to the connection depending on the assigned service.      In the Simple Abstract Model a connection is assigned a priority         when it is established.  It may be assumed that for connections         that share the same output port, a cell or frame on a         connection with a higher priority is much more likely to exit         the switch before a cell or frame on a connection with a lower         priority if they are both in the switch at the same time.      The QoS Profile Model provides a simple mechanism that allows QoS         semantics defined externally to GSMP to be assigned to         connections.  Each profile is an opaque indicator that has been         predefined in the controller and in the switch.4. Summary of Message Set   The following table gives a summary of the messages defined in this   version of the specification.  It also makes a recommendation of the   minimal set of messages that should be supported in an MPLS   environment.  These messages will be labelled as "Required", though   the service provided by the other messages are essential for the   operation of carrier quality controller/switch operations.  GSMPv1.1   or GSMPv2 commands that are no longer support are marked as   "Obsolete" and should no longer be used.Doria & Sundell              Informational                      [Page 5]

RFC 3294                   GSMP Applicability                  June 20024.1 Messages Table   Message Name                      Message Number  Status   Connection Management Messages        Add Branch........................16          Required            ATM Specific - VPC............26        Delete Tree.......................18        Verify Tree.......................19          Obsoleted        Delete All Input..................20        Delete All Output.................21        Delete Branches...................17          Required        Move Output Branch................22            ATM Specific - VPC............27        Move Input Branch.................23            ATM Specific - VPC............28   Port Management Messages        Port Management...................32          Required        Label Range.......................33   State and Statistics Messages        Connection Activity...............48        Port Statistics...................49          Required        Connection Statistics.............50        QoS Class Statistics..............51          Reserved        Report Connection State...........52   Configuration Messages        Switch Configuration..............64          Required        Port Configuration................65          Required        All Ports Configuration...........66          Required        Service Configuration.............67   Reservation Messages        Reservation Request...............70          Required        Delete Reservation................71          Required        Delete All Reservations...........72   Event Messages        Port Up...........................80        Port Down.........................81        Invalid Label.....................82        New Port..........................83        Dead Port.........................84Doria & Sundell              Informational                      [Page 6]

RFC 3294                   GSMP Applicability                  June 2002      Abstract and Resource Model Extension Messages          Reserved.Message Range.........200-249      Adjacency Protocol.................10           Required5. Security Considerations   The security of GSMP's TCP/IP control channel has been addressed in   [4].  For all uses of GSMP over an IP network, it is REQUIRED that   GSMP be run over TCP/IP using the security considerations discussed   in [4].References   [1] Sjostrand, H., Buerkle, J. and B. Srinivasan, "Definitions of       Managed Objects for the General Switch Management Protocol       (GSMP)",RFC 3295, June 2002.   [2] Newman, P., Edwards, W., Hinden, R., Hoffman, E., Ching Liaw, F.,       Lyon, T. and Minshall, G., "Ipsilon's General Switch Management       Protocol Specification Version 1.1",RFC 1987, August 1996.   [3] Newman, P., Edwards, W., Hinden, R., Hoffman, E., Ching Liaw, F.,       Lyon, T. and G. Minshall, "Ipsilon's General Switch Management       Protocol Specification Version 2.0",RFC 2297, March 1998.   [4] Worster, T., Doria, A. and J. Buerkle, "General Switch Management       Protocol (GSMP) Packet Encapsulations for Asynchronous Transfer       Mode (ATM), Ethernet and Transmission Control Protocol (TCP)",RFC 3293, June 2002.   [5] Doria, A., Sundell, K., Hellstrand, F. and T. Worster, "General       Switch Management Protocol (GSMP) V3",RFC 3292, June 2002.Doria & Sundell              Informational                      [Page 7]

RFC 3294                   GSMP Applicability                  June 2002Authors' Addresses   Avri Doria   Div. of Computer Communications   Lulea University of Technology   S-971 87 Lulea   Sweden   Phone: +1 401 663 5024   EMail: avri@acm.org   Kenneth Sundell   Nortel Networks AB   S:t Eriksgatan 115 A   P.O. Box 6701   SE-113 85 Stockholm Sweden   EMail: sundell@nortelnetworks.comDoria & Sundell              Informational                      [Page 8]

RFC 3294                   GSMP Applicability                  June 2002Full Copyright Statement   Copyright (C) The Internet Society (2002).  All Rights Reserved.   This document and translations of it may be copied and furnished to   others, and derivative works that comment on or otherwise explain it   or assist in its implementation may be prepared, copied, published   and distributed, in whole or in part, without restriction of any   kind, provided that the above copyright notice and this paragraph are   included on all such copies and derivative works.  However, this   document itself may not be modified in any way, such as by removing   the copyright notice or references to the Internet Society or other   Internet organizations, except as needed for the purpose of   developing Internet standards in which case the procedures for   copyrights defined in the Internet Standards process must be   followed, or as required to translate it into languages other than   English.   The limited permissions granted above are perpetual and will not be   revoked by the Internet Society or its successors or assigns.   This document and the information contained herein is provided on an   "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING   TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING   BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION   HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.Acknowledgement   Funding for the RFC Editor function is currently provided by the   Internet Society.Doria & Sundell              Informational                      [Page 9]