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Versions: 00 01 03 04 05 06 07 08 09 rfc3430                            
Network Working Group                           J. Schoenwaelder, Editor
Internet-Draft                                           TU Braunschweig
Expires September 1999                                     23 March 1999


                    SNMP over TCP Transport Mapping

                   <draft-irtf-nmrg-snmp-tcp-00.txt>

Status of this Memo

   This document is an Internet-Draft and is in full conformance with
   all provisions of Section 10 of RFC 2026.  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
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   The list of current Internet-Drafts can be accessed at
   http://www.ietf.org/ietf/1id-abstracts.txt

   The list of Internet-Draft Shadow Directories can be accessed at
   http://www.ietf.org/shadow.html

   Distribution of this document is unlimited. Please send comments to
   the Network Management Research Group, <nmrg@ibr.cs.tu-bs.de>.

Copyright Notice

   Copyright (C) The Internet Society (1999).  All Rights Reserved.

Abstract

   This memo defines a transport mapping for using the Simple Network
   Management Protocol (SNMP) over TCP. The transport mapping defined in
   this memo can be used with any version of SNMP.











J. Schoenwaelder                                                [Page 1]


Internet-Draft      SNMP over TCP Transport Mapping         January 1999


   Table of Contents

   1 Introduction .................................................    3
   2 Definitions ..................................................    3
   3 SNMP over TCP ................................................    4
   3.1 Serialization ..............................................    4
   3.2 Well-known Values ..........................................    4
   3.3 Connection Management ......................................    5
   4 Acknowledgments ..............................................    5
   5 Editor's Address .............................................    5
   6 Full Copyright Statement .....................................    6








































J. Schoenwaelder                                                [Page 2]


Internet-Draft      SNMP over TCP Transport Mapping         January 1999


1.  Introduction

   This memo defines a transport mapping for using the Simple Network
   Management Protocol (SNMP) over TCP. The transport mapping defined in
   this memo can be used with any version of SNMP. This document extends
   the transport mappings defined in RFC 1906.

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119.


2.  Definitions

   IRTF-NMRG-SNMP-TM DEFINITIONS ::= BEGIN

   IMPORTS
       MODULE-IDENTITY, OBJECT-IDENTITY, experimental
           FROM SNMPv2-SMI
       TEXTUAL-CONVENTION
           FROM SNMPv2-TC;

   nmrgSnmpDomains MODULE-IDENTITY
       LAST-UPDATED "9903231800Z"
       ORGANIZATION "IRTF Network Management Research Group"
       CONTACT-INFO
           "Juergen Schoenwaelder
            TU Braunschweig
            Bueltenweg 74/75
            38106 Braunschweig
            Germany
            Tel: +49 531 391-3283
            E-mail: schoenw@ibr.cs.tu-bs.de"
       DESCRIPTION
           "This MIB module defines the SNMP over TCP transport mapping."
       ::= { experimental nmrg(xxxx) 1 }

   -- SNMP over TCP over IPv4

   snmpTCPDomain   OBJECT-IDENTITY
       STATUS      current
       DESCRIPTION
           "The SNMP over TCP/IPv4 transport domain. The corresponding
            transport address is of type SnmpTCPAddress."
       ::= { nmrgSnmpDomains 6 }   -- matches first unused value
                                   -- below snmpDomains





J. Schoenwaelder                                                [Page 3]


Internet-Draft      SNMP over TCP Transport Mapping         January 1999


   SnmpTCPAddress ::= TEXTUAL-CONVENTION
       DISPLAY-HINT "1d.1d.1d.1d/2d"
       STATUS       current
       DESCRIPTION
               "Represents a TCP/IPv4 address:

                  octets   contents        encoding
                   1-4     IP-address      network-byte order
                   5-6     TCP-port        network-byte order
               "
       SYNTAX      OCTET STRING (SIZE (6))
   END


3.  SNMP over TCP

   This is an optional transport mapping. However, implementors are
   encouraged to support SNMP over TCP whenever possible because this
   enables applications to use more efficient MIB data transfers.


3.1.  Serialization

   Each instance of a message is serialized into a single BER encoded
   message, using the algorithm specified in Section 8 of RFC 1906.  The
   BER encoded message is then send over a TCP connection.

   Note, it is possible to exchange multiple SNMP request/response pairs
   over a single TCP connection. The length field in the BER encoded
   SNMP message is used to separate multiple requests send over a single
   TCP connection.


3.2.  Well-known Values

   It is suggested that administrators configure their SNMP entities
   acting in an agent role to listen on TCP port 161 for incoming
   connections.  Further, it is suggested that notification sinks be
   configured to listen on TCP port 162.

   When an SNMP entity uses this transport mapping, it must be capable
   of accepting messages that are at least 484 octets in size.
   Implementation of larger values is encouraged whenever possible.








J. Schoenwaelder                                                [Page 4]


Internet-Draft      SNMP over TCP Transport Mapping         January 1999


3.3.  Connection Management

   The use of TCP connections introduces costs. Connection establishment
   and shutdown causes additional traffic on the wire. Further,
   maintaining open connections binds resources in the network layer of
   the underlying operating system.

   TCP connections should therefore only be used when the size of the
   data transferred would otherwise cause large latencies due to small
   UDP packet sizes and an increased number of interactions.

   Both, an SNMP entity in the agent role and an SNMP entity in the
   manager role, are allowed to close the connections at any point in
   time. This ensures that SNMP entities can control their resource
   usage and shutdown TCP connections that are not used. Note, SNMP
   engines are not expected to process any outstanding requests if the
   underlying TCP connection has been closed. A no response error
   condition SHOULD be signalled for outstanding requests for command
   generator applications if the TCP connection is closed.


4.  Acknowledgments

   The definitions in this memo are inspired by definitions found in RFC
   1906. This document is the result of the Network Management Research
   Group (NMRG). Special thanks go to the following participants for
   their comments and contributions:

   Luca Deri, Jean-Philippe Martin-Flatin, Aiko Pras, Ron Sprenkels,
   Bert Wijnen


5.  Editor's Address

     Juergen Schoenwaelder             Email: schoenw@ibr.cs.tu-bs.de
     TU Braunschweig                     Tel: +49 531 391-3283
     Bueltenweg 74/75
     38106 Braunschweig
     Germany












J. Schoenwaelder                                                [Page 5]


Internet-Draft      SNMP over TCP Transport Mapping         January 1999


6.  Full Copyright Statement

   Copyright (C) The Internet Society (1998). 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.
























J. Schoenwaelder                                                [Page 6]