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                                Transport Mappings
                                     for the
                    Simple Management Protocol (SMP) Framework

                             Sat Jul  4 17:76:05 1992


                                 Jeffrey D. Case
                               SNMP Research, Inc.
                        University of Tennessee, Knoxville
                                 case@cs.utk.edu


                                 Keith McCloghrie
                                Hughes LAN Systems
                                   kzm@hls.com


                                 Marshall T. Rose
                           Dover Beach Consulting, Inc.
                              mrose@dbc.mtview.ca.us


                               Steven L. Waldbusser
                            Carnegie Mellon University
                            waldbusser@andrew.cmu.edu






          1.  Status of this Memo

          This document is an Internet Draft.  Internet Drafts are
          working documents of the Internet Engineering Task Force
          (IETF), its Areas, and its Working Groups.  Note that other
          groups may also distribute working documents as Internet
          Drafts.

          Internet Drafts are draft documents valid for a maximum of six
          months.  Internet Drafts may be updated, replaced, or
          obsoleted by other documents at any time.  It is not
          appropriate to use Internet Drafts as reference material or to
          cite them other than as a "working draft" or "work in





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          progress".

          Please check the 1id-abstracts.txt listing contained in the
          internet-drafts Shadow Directories on nic.ddn.mil,
          nnsc.nsf.net, nic.nordu.net, ftp.nisc.sri.com, or
          munnari.oz.au to learn the current status of any Internet
          Draft.

          Please send comments to the SNMP discussion group,
          <snmp@psi.com>.








































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          2.  Introduction

          A network management system contains: several (potentially
          many) nodes, each with management instrumentation termed an
          agent; at least one management station; and, a management
          protocol, which is used to convey management information
          between the agents and management stations.  Operations of the
          protocol are carried out under an administrative framework
          which defines both authentication and authorization policies.

          Network management stations execute management applications
          which monitor and control network elements.  Network elements
          are devices such as hosts, routers, terminal servers, etc.,
          which are monitored and controlled through access to their
          management information.

          The management protocol, termed the Simple Management Protocol
          (SMP), may be used over a variety of protocol suites.  It is
          the purpose of this document to define how the SMP maps onto
          an initial set of transport domains.  Other mappings may be
          defined in the future.

          Although several mappings are defined, the mapping onto UDP is
          the preferred mapping.  As such, to provide for the greatest
          level of interoperability, systems which choose to deploy
          other mappings should also provide for proxy service to the
          UDP mapping.























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          3.  Definitions

          SMP-TM DEFINITIONS ::= BEGIN

          IMPORTS
              smpMappings
                  FROM SMP-SMI
              TEXTUAL-CONVENTION, DisplayString
                  FROM SMP-TC;


          smpDomains   OBJECT IDENTIFIER ::= { smpMappings 1 }


          -- SMP over UDP

          smpUDPdomain  OBJECT IDENTIFIER ::= { smpDomains 1 }
          -- for an SmpUDPAddress of length 6:
          --
          -- octets   contents        encoding
          --  1-4     IP-address      network-byte order
          --  5-6     UDP-port        network-byte order
          --
          SmpUDPAddress TEXTUAL-CONVENTION
              DISPLAY-HINT "1d.1d.1d.1d/2d"
              DESCRIPTION
                      "Represents a UDP-address."
              ::= OCTET STRING (SIZE (6))






















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          -- SMP over OSI

          smpOSIclnsDomain  OBJECT IDENTIFIER ::= { smpDomains 2 }
          smpOSIconsDomain  OBJECT IDENTIFIER ::= { smpDomains 3 }
          -- for an SmpOSIAddress of length m:
          --
          -- octets   contents            encoding
          --    1     length of NSAP      "n" as an unsigned-integer
          --                                (either 0 or from 3 to 20)
          -- 2..(n+1) NSAP                concrete binary representation
          -- (n+2)..m TSEL                string or (up to 64) octets
          --
          SmpOSIAddress TEXTUAL-CONVENTION
              DISPLAY-HINT "*1x:/1x:"
              DESCRIPTION
                      "Represents an OSI transport-address."
              ::= OCTET STRING (SIZE (1..85))


          -- SMP over DDP

          smpDDPDomain  OBJECT IDENTIFIER ::= { smpDomains 4 }
          -- for an SmpNBPAddress of length m:
          --
          -- octets   contents            encoding
          --   1      length of Object    "n" as an unsigned integer
          -- 2..(n+1) Object              string of (up to 32) octets
          -- (n+2)..m Zone                string of (up to 32) octets
          --
          SmpNBPAddress TEXTUAL-CONVENTION
              DESCRIPTION
                      "Represents an NBP-name."
              ::= OCTET STRING (SIZE (3..65))

















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          -- SMP over IPX

          smpIPXDomain  OBJECT IDENTIFIER ::= { smpDomains 5 }
          -- for an SmpIPXAddress of length 12:
          --
          -- octets   contents            encoding
          --  1-4     network-number      network-byte order
          --  5-10    physical-address    network-byte order
          -- 11-12    socket-number       network-byte order
          --
          SmpIPXAddress TEXTUAL-CONVENTION
              DISPLAY-HINT "4x.1x:1x:1x:1x:1x:1x.2d"
              DESCRIPTION
                      "Represents an IPX-address."
              ::= OCTET STRING (SIZE (12))


          -- restart domain

          restartDomain  OBJECT IDENTIFIER ::= { smpDomains 6 }
          RestartAddress TEXTUAL-CONVENTION
              DESCRIPTION
                      "Represents a local configuration store, e.g., the
                      name of a memory or disk file."
              ::= DisplayString


          -- entity domain

          entityDomain  OBJECT IDENTIFIER ::= { smpDomains 7 }
          EntityAddress TEXTUAL-CONVENTION
              DESCRIPTION
                      "Represents an administratively assigned name,
                      chosen for mnemonic and human-understandability,
                      for a local attached entity (e.g., a hardware or
                      software device)."
              ::= DisplayString













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          -- for proxy to community-based SNMP (RFC 1157)

          -- uses smpUDPAddress
          rfc1157Domain  OBJECT IDENTIFIER ::= { smpDomains 8 }

          -- the community-based noAuth
          rfc1157noAuth  OBJECT IDENTIFIER ::= { smpDomains 9 }


          END








































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          4.  SMP over UDP

          This is the preferred transport mapping.


          4.1.  Serialization

          Each instance of a message is serialized onto a single UDP[1]
          datagram, using the algorithm specified in Section 11.


          4.2.  Well-known Values

          Although the partyTable gives transport addressing information
          for an SMP party, it is suggested that administrators
          configure their SMP entities acting in an agent role to listen
          on UDP port 161.  Further, it is suggested that trap sinks be
          configured to listen on UDP port 162.

          The partyTable also lists the maximum message size which a SMP
          party is willing to accept.  This value must be at least 484
          octets.  Implementation of larger values is encouraged
          whenever possible.



























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          5.  SMP over OSI

          This is an optional transport mapping.


          5.1.  Serialization

          Each instance of a message is serialized onto a single TSDU
          [2,3] for the OSI Connectionless-mode Transport Service
          (CLTS), using the algorithm specified in Section 11.


          5.2.  Well-known Values

          Although the partyTable gives transport addressing information
          for an SMP party, it is suggested that administrators
          configure their SMP entities acting in an agent role to listen
          on transport selector "smp-cl" (which consists of six ASCII
          characters), when using a CL-mode network service to realize
          the CLTS.  Further, it is suggested that trap sinks be
          configured to listen on transport selector "smpt-cl" (which
          consists of seven ASCII characters) when using a CL-mode
          network service to realize the CLTS.  Similarly, when using a
          CO-mode network service to realize the CLTS, the suggested
          transport selectors are "smp-co"  and "smpt-co", for agent and
          trap sink, respectively.

          The partyTable also lists the maximum message size which a SMP
          party is willing to accept.  This value must be at least 484
          octets.  Implementation of larger values is encouraged
          whenever possible.



















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          6.  SMP over DDP

          This is an optional transport mapping.


          6.1.  Serialization

          Each instance of a message is serialized onto a single DDP
          datagram [4], using the algorithm specified in Section 11.


          6.2.  Well-known Values

          SMP messages are sent using DDP protocol type 8.  SMP entities
          acting in an agent role listens on DDP socket number 8, whilst
          trap sinks listen on DDP socket 9.

          Although the partyTable gives transport addressing information
          for an SMP party, it is suggested that administrators
          configure their SMP entities acting in an agent role to use
          NBP type "SMP Agent" (which consists of nine ASCII
          characters), whilst trap sinks should be  configured to use
          NBP type "SMP Trap Handler" (which consists of sixteen ASCII
          characters).

          The partyTable also lists the maximum message size which a SMP
          party is willing to accept.  This value must be at least 484
          octets.  Implementation of larger values is encouraged
          whenever possible.





















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          7.  SMP over IPX

          This is an optional transport mapping.


          7.1.  Serialization

          Each instance of a message is serialized onto a single IPX
          datagram [5], using the algorithm specified in Section 11.


          7.2.  Well-known Values

          Although the partyTable gives transport addressing information
          for an SMP party, it is suggested that administrators
          configure their SMP entities acting in an agent role to listen
          on IPX socket 36879 (900f hexadecimal).  Further, it is
          suggested that trap sinks be configured to listen on IPX
          socket 36880 (9010 hexadecimal)

          The partyTable also lists the maximum message size which a SMP
          party is willing to accept.  This value must be at least 546
          octets.  Implementation of larger values is encouraged
          whenever possible.


























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          8.  Restart Domain

          This is an optional transport mapping.


          8.1.  Usage

          The restart domain is used as the transport domain of a party
          which has a MIB view containing the values of managed objects
          to be used on a restart of a device.  Hence, the use of such a
          party to manipulate variables does not affect the running
          system; rather, the changes will be in effect only after the
          device next restarts.





































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          9.  Entity Domain

          This is an optional transport mapping.


          9.1.  Usage

          The entity domain is used to name locally attached software or
          hardware entities that can be managed through a proxy
          mechanism through the local agent.  For example, the entity
          domain may address multiple repeaters in a hub or multiple
          AppleTalk protocol stacks on a computer system.






































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          10.  Proxy to community-based SNMP

          In order to provide proxy to community-based SNMP [6], some
          definitions are necessary for both transport domains and
          authentication protocols.


          10.1.  Transport Domain: rfc1157Domain

          The transport domain, rfc1157Domain, indicates the transport
          mapping for community-based SNMP messages defined in RFC 1157.
          When a party's transport domain (partyTDomain) is
          rfc1157Domain:

          (1)  the party's transport address (partyTAddress) shall be 6
               octets long, the initial 4 octets containing the IP-
               address in network-byte order, and the last two octets
               containing the UDP port in network-byte order; and,

          (2)  the party's authentication protocol (partyAuthProtocol)
               shall be rfc1157noAuth.


          10.2.  Authentication Algorithm: rfc1157noAuth

          A party's authentication protocol (partyAuthProtocol)
          specifies the protocol and mechanism by which the party
          authenticates the integrity and origin of the SNMP or SMP PDUs
          it generates.  When a party's authentication protocol is
          rfc1157noAuth:

          (1)  the party's public authentication key (partyAuthPublic),
               clock (partyAuthClock), and lifetime (partyAuthLifetime)
               are irrelevant; and,

          (2)  the party's private authentication key
               (partySecretsAuthPrivate) shall be used as the 1157
               community for the proxy target, and shall be at least one
               octet in length (no maximum length is specified).

          Note that when setting the party's private authentication key,
          the exclusive-OR semantics specified in [7] still apply.








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          11.  Serialization using the Basic Encoding Rules

          When the Basic Encoding Rules [8] are used for serialization:

          (1)  When encoding the length field, only the definite form is
               used; use of the indefinite form encoding is prohibited.
               Note that when using the definite-long form, it is
               permissible to use more than the minimum number of length
               octets necessary to encode the length field.

          (2)  When encoding the value field, the primitive form is used
               whenever possible.

          (3)  When a BIT STRING is serialized, all named-bits are
               transferred regardless of their truth-value.  Further, if
               the number of named-bits is not an integral multiple of
               eight, then the fewest number of additional zero-valued
               bits are transferred so that an integral multiple of
               eight bits is transferred.

          These restrictions apply to all aspects of ASN.1 encoding,
          both for the protocol data units and the data objects they
          contain.



























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          11.1.  Usage Example

          As an example of applying the Basic Encoding Rules, suppose
          one wanted to encode an instance of the GetBulkRequest-PDU
          [9]:

               [5] IMPLICIT SEQUENCE {
                       request-id      1414684022,
                       non-repeaters   1,
                       max-repetitions 2,
                       variable-bindings {
                           { name sysUpTime,
                             value { unspecified NULL } },
                           { name ipNetToMediaPhysAddress,
                             value { unspecified NULL } },
                           { name ipNetToMediaType,
                             value { unspecified NULL } },
                       }
                   }

          Applying the BER, this would be encoded (in hexadecimal) as:

          [5] IMPLICIT SEQUENCE          a5 39
              INTEGER                    02 04 52 54 5d 76
              INTEGER                    02 01 01
              INTEGER                    02 01 02
              SEQUENCE                   30 2b
                  SEQUENCE               30 0b
                      OBJECT IDENTIFIER  06 07 2b 06 01 02 01 01 03
                      NULL               05 00
                  SEQUENCE               30 0d
                      OBJECT IDENTIFIER  06 09 2b 06 01 02 01 04 16 01 02
                      NULL               05 00
                  SEQUENCE               30 0d
                      OBJECT IDENTIFIER  06 09 2b 06 01 02 01 04 16 01 04
                      NULL               05 00














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          12.  Acknowledgements

          The UDP-based mapping is based, in part, on RFC 1157.

          The OSI-based mapping is based, in part, on RFC 1283.

          The DDP-based mapping is based, in part, on earlier work by
          Greg Minshall of Novell, Inc., and Mike Ritter of Apple
          Computer, Inc.

          The IPX-based mapping is based, in part, on RFC 1298.

          The section on proxy to community-based SNMP is based on
          earlier work that was based in part on a suggestion by
          Jonathan Biggar of Netlabs, Inc.



































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          13.  References

          [1]  J.B. Postel, User Datagram Protocol, Request for Comments
               768.  (August, 1980).

          [2]  Information processing systems - Open Systems
               Interconnection - Transport Service Definition,
               International Organization for Standardization.
               International Standard 8072, (June, 1986).

          [3]  Information processing systems - Open Systems
               Interconnection - Transport Service Definition - Addendum
               1: Connectionless-mode Transmission, International
               Organization for Standardization.  International Standard
               8072/AD 1, (December, 1986).

          [4]  Network System Technical Interface Overview.  Novell,
               Inc, (June, 1989).

          [5]  G. Sidhu, R. Andrews, A. Oppenheimer, Inside AppleTalk
               (second edition).  Addison-Wesley, 1990.

          [6]  J.D. Case, M.S. Fedor, M.L. Schoffstall, and J.R. Davin,
               Simple Network Management Protocol.  Request for Comments
               1157, (May, 1990).

          [7]  K. McCloghrie, J.R. Davin, J.M. Galvin, Definitions of
               Managed Objects for Administration of SNMP Parties.
               Request for Comments 1353, (July, 1992).

          [8]  Information processing systems - Open Systems
               Interconnection - Specification of Basic Encoding Rules
               for Abstract Syntax Notation One (ASN.1), International
               Organization for Standardization.  International Standard
               8825, (December, 1987).

          [9]  J.D. Case, K. McCloghrie, M.T. Rose, S.L. Waldbusser,
               Protocol Operations for the Simple Management Protocol
               (SMP) Framework, (July, 1992).











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          Table of Contents


          1 Status of this Memo ...................................    1
          2 Introduction ..........................................    3
          3 Definitions ...........................................    4
          4 SMP over UDP ..........................................    8
          4.1 Serialization .......................................    8
          4.2 Well-known Values ...................................    8
          5 SMP over OSI ..........................................    9
          5.1 Serialization .......................................    9
          5.2 Well-known Values ...................................    9
          6 SMP over DDP ..........................................   10
          6.1 Serialization .......................................   10
          6.2 Well-known Values ...................................   10
          7 SMP over IPX ..........................................   11
          7.1 Serialization .......................................   11
          7.2 Well-known Values ...................................   11
          8 Restart Domain ........................................   12
          8.1 Usage ...............................................   12
          9 Entity Domain .........................................   13
          9.1 Usage ...............................................   13
          10 Proxy to community-based SNMP ........................   14
          10.1 Transport Domain: rfc1157Domain ....................   14
          10.2 Authentication Algorithm: rfc1157noAuth ............   14
          11 Serialization using the Basic Encoding Rules .........   15
          11.1 Usage Example ......................................   16
          12 Acknowledgements .....................................   17
          13 References ...........................................   18





















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