Network Working Group J. Schoenwaelder, Editor Internet-Draft TU Braunschweig Expires September 1999 23 March 1999 SNMP over TCP Transport Mapping 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, . 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]