RFC3019

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Network Working Group B. Haberman Request for Comments: 3019 Nortel Networks Category: Standards Track R. Worzella

                                                                 IBM
                                                        January 2001
         IP Version 6 Management Information Base for
           The Multicast Listener Discovery Protocol

Status of this Memo

This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited.

Copyright Notice

Copyright (C) The Internet Society (2001). All Rights Reserved.

Abstract

This document defines a portion of the Management Information Base (MIB) for use with network management protocols in Internet Protocol Version 6 internets. Specifically, this document is the MIB module that defines managed objects for implementations of the Multicast Listener Discovery Protocol RFC2710.

Terminology

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 RFC2119.

The SNMP Management Framework

The SNMP Management Framework presently consists of five major components:

An overall architecture, described in RFC 2571 RFC2571.

Mechanisms for describing and naming objects and events for the purpose of management. The first version of this Structure of Management Information (SMI) is called SMIv1 and described in STD 16,

RFC 1155 RFC1155, STD 16, RFC 1212 RFC1212 and RFC 1215 RFC1215. The second version, called SMIv2, is described in STD 58, RFC 2578 RFC2578, STD 58, RFC 2579 RFC2579 and STD 58, RFC 2580 RFC2580.

Message protocols for transferring management information. The first version of the SNMP message protocol is called SNMPv1 and described in STD 15, RFC 1157 RFC1157. A second version of the SNMP message protocol, which is not an Internet standards track protocol, is called SNMPv2c and described in RFC 1901 RFC1901 and RFC 1906 RFC1906. The third version of the message protocol is called SNMPv3 and described in RFC 1906 RFC1906, RFC 2572 RFC2572 and RFC 2574 RFC2574.

Protocol operations for accessing management information. The first set of protocol operations and associated PDU formats is described in STD 15, RFC 1157 RFC1157. A second set of protocol operations and associated PDU formats is described in RFC 1905 RFC1905.

A set of fundamental applications described in RFC 2573 RFC2573 and the view-based access control mechanism described in RFC 2575 RFC2575.

A more detailed introduction to the current SNMP Management Framework can be found in RFC 2570 RFC2570.

Managed objects are accessed via a virtual information store, termed the Management Information Base or MIB. Objects in the MIB are defined using the mechanisms defined in the SMI.

This memo specifies a MIB module that is compliant to the SMIv2. A MIB conforming to the SMIv1 can be produced through the appropriate translations. The resulting translated MIB must be semantically equivalent, except where objects or events are omitted because no translation is possible (use of Counter64). Some machine-readable information in SMIv2 will be converted into textual descriptions in SMIv1 during the translation process. However, this loss of machine-readable information is not considered to change the semantics of the MIB.

Overview

This MIB module contains two tables:

  1. The MLD Interface Table, which contains one row for each
     interface on which MLD is enabled.
  2. The MLD Cache Table which contains one row for each IPv6
     Multicast group for which there are members on a particular
     interface.

Both tables are intended to be implemented by hosts and routers. Some objects in each table apply to routers only.

Definitions

IPV6-MLD-MIB DEFINITIONS ::= BEGIN

IMPORTS

   MODULE-IDENTITY, OBJECT-TYPE, Counter32, Gauge32,
   Unsigned32, TimeTicks, mib-2     FROM SNMPv2-SMI
   RowStatus, TruthValue            FROM SNMPv2-TC
   InetAddressIPv6             FROM INET-ADDRESS-MIB
   InterfaceIndex, InterfaceIndexOrZero
                                        FROM IF-MIB
   MODULE-COMPLIANCE, OBJECT-GROUP  FROM SNMPv2-CONF;

mldMIB MODULE-IDENTITY

   LAST-UPDATED "200101250000Z" -- 25 Jan 2001
   ORGANIZATION "IETF IPNGWG Working Group."
   CONTACT-INFO
           " Brian Haberman
             Nortel Networks
             4309 Emperor Blvd.
             Durham, NC  27703
             USA
             Phone: +1 919 992 4439
             e-mail: [email protected]"
   DESCRIPTION
           "The MIB module for MLD Management."
   REVISION "200101250000Z" -- 25 Jan 2001
   DESCRIPTION
           "Initial version, published as RFC 3019."
   ::= { mib-2 91 }

mldMIBObjects OBJECT IDENTIFIER ::= { mldMIB 1 } -- -- The MLD Interface Table --

mldInterfaceTable OBJECT-TYPE

   SYNTAX     SEQUENCE OF MldInterfaceEntry
   MAX-ACCESS not-accessible
   STATUS     current
   DESCRIPTION
            "The (conceptual) table listing the interfaces on which
            MLD is enabled."
   ::= { mldMIBObjects 1 }

mldInterfaceEntry OBJECT-TYPE

   SYNTAX     MldInterfaceEntry
   MAX-ACCESS not-accessible
   STATUS     current
   DESCRIPTION
           "An entry (conceptual row) representing an interface on
           which MLD is enabled."
   INDEX      { mldInterfaceIfIndex }
   ::= { mldInterfaceTable 1 }

MldInterfaceEntry ::= SEQUENCE {

   mldInterfaceIfIndex               InterfaceIndex,
   mldInterfaceQueryInterval         Unsigned32,
   mldInterfaceStatus                RowStatus,
   mldInterfaceVersion               Unsigned32,
   mldInterfaceQuerier               InetAddressIPv6,
   mldInterfaceQueryMaxResponseDelay Unsigned32,
   mldInterfaceJoins                 Counter32,
   mldInterfaceGroups                Gauge32,
   mldInterfaceRobustness            Unsigned32,
   mldInterfaceLastListenQueryIntvl  Unsigned32,
   mldInterfaceProxyIfIndex          InterfaceIndexOrZero,
   mldInterfaceQuerierUpTime         TimeTicks,
   mldInterfaceQuerierExpiryTime     TimeTicks

}

mldInterfaceIfIndex OBJECT-TYPE

   SYNTAX     InterfaceIndex
   MAX-ACCESS not-accessible
   STATUS     current
   DESCRIPTION
           "The internetwork-layer interface value of the interface
           for which MLD is enabled."
   ::= { mldInterfaceEntry 1 }

mldInterfaceQueryInterval OBJECT-TYPE

   SYNTAX     Unsigned32
   UNITS      "seconds"
   MAX-ACCESS read-create
   STATUS     current
   DESCRIPTION
           "The frequency at which MLD Host-Query packets are
           transmitted on this interface."
   DEFVAL     { 125 }
   ::= { mldInterfaceEntry 2 }

mldInterfaceStatus OBJECT-TYPE

   SYNTAX     RowStatus
   MAX-ACCESS read-create
   STATUS     current
   DESCRIPTION
            "The activation of a row enables MLD on the interface.
            The destruction of a row disables MLD on the interface."
   ::= { mldInterfaceEntry 3 }

mldInterfaceVersion OBJECT-TYPE

   SYNTAX     Unsigned32
   MAX-ACCESS read-create
   STATUS     current
   DESCRIPTION
            "The version of MLD which is running on this interface.
            This object is a place holder to allow for new versions
            of MLD to be introduced.  Version 1 of MLD is defined
            in RFC 2710."
   DEFVAL     { 1 }
   ::= { mldInterfaceEntry 4 }

mldInterfaceQuerier OBJECT-TYPE

   SYNTAX     InetAddressIPv6 (SIZE (16))
   MAX-ACCESS read-only
   STATUS     current
   DESCRIPTION
            "The address of the MLD Querier on the IPv6 subnet to
            which this interface is attached."
   ::= { mldInterfaceEntry 5 }

mldInterfaceQueryMaxResponseDelay OBJECT-TYPE

   SYNTAX     Unsigned32
   UNITS      "seconds"
   MAX-ACCESS read-create
   STATUS     current
   DESCRIPTION
           "The maximum query response time advertised in MLD
           queries on this interface."
   DEFVAL     { 10 }
   ::= { mldInterfaceEntry 6 }

mldInterfaceJoins OBJECT-TYPE

   SYNTAX     Counter32
   MAX-ACCESS read-only
   STATUS     current
   DESCRIPTION
           "The number of times a group membership has been added on
           this interface; that is, the number of times an entry for
           this interface has been added to the Cache Table.  This
           object gives an indication of the amount of MLD activity
           over time."
   ::= { mldInterfaceEntry 7 }

mldInterfaceGroups OBJECT-TYPE

   SYNTAX     Gauge32
   MAX-ACCESS read-only
   STATUS     current
   DESCRIPTION
           "The current number of entries for this interface in the
           Cache Table."
   ::= { mldInterfaceEntry 8 }

mldInterfaceRobustness OBJECT-TYPE

   SYNTAX     Unsigned32
   MAX-ACCESS read-create
   STATUS     current
   DESCRIPTION
           "The Robustness Variable allows tuning for the expected
           packet loss on a subnet.  If a subnet is expected to be
           lossy, the Robustness Variable may be increased.  MLD is
           robust to (Robustness Variable-1) packet losses.  The
           discussion of the Robustness Variable is in Section 7.1
           of RFC 2710."
   DEFVAL     { 2 }
   ::= { mldInterfaceEntry 9 }

mldInterfaceLastListenQueryIntvl OBJECT-TYPE

   SYNTAX     Unsigned32
   UNITS      "seconds"
   MAX-ACCESS read-create
   STATUS     current
   DESCRIPTION
            "The Last Member Query Interval is the Max Response
            Delay inserted into Group-Specific Queries sent in
            response to Leave Group messages, and is also the amount
            of time between Group-Specific Query messages.  This
            value may be tuned to modify the leave latency of the
            network.  A reduced value results in reduced time to
            detect the loss of the last member of a group."
   DEFVAL     { 1 }
   ::= { mldInterfaceEntry 10 }

mldInterfaceProxyIfIndex OBJECT-TYPE

   SYNTAX     InterfaceIndexOrZero
   MAX-ACCESS read-create
   STATUS     current
   DESCRIPTION
            "Some devices implement a form of MLD proxying whereby
            memberships learned on the interface represented by this
            row, cause MLD Multicast Listener Reports to be sent on
            the internetwork-layer interface identified by this
            object.  Such a device would implement mldRouterMIBGroup
            only on its router interfaces (those interfaces with
            non-zero mldInterfaceProxyIfIndex).  Typically, the
            value of this object is 0, indicating that no proxying
            is being done."
   DEFVAL     { 0 }
   ::= { mldInterfaceEntry 11 }

mldInterfaceQuerierUpTime OBJECT-TYPE

   SYNTAX     TimeTicks
   MAX-ACCESS read-only
   STATUS     current
   DESCRIPTION
           "The time since mldInterfaceQuerier was last changed."
   ::= { mldInterfaceEntry 12 }

mldInterfaceQuerierExpiryTime OBJECT-TYPE

   SYNTAX     TimeTicks
   MAX-ACCESS read-only
   STATUS     current
   DESCRIPTION
           "The time remaining before the Other Querier Present
           Timer expires.  If the local system is the querier,
           the value of this object is zero."
   ::= { mldInterfaceEntry 13 }

-- -- The MLD Cache Table --

mldCacheTable OBJECT-TYPE

   SYNTAX     SEQUENCE OF MldCacheEntry
   MAX-ACCESS not-accessible
   STATUS     current
   DESCRIPTION
            "The (conceptual) table listing the IPv6 multicast
            groups for which there are members on a particular
            interface."
   ::= { mldMIBObjects 2 }

mldCacheEntry OBJECT-TYPE

   SYNTAX     MldCacheEntry
   MAX-ACCESS not-accessible
   STATUS     current
   DESCRIPTION
           "An entry (conceptual row) in the mldCacheTable."
   INDEX      { mldCacheAddress, mldCacheIfIndex }
   ::= { mldCacheTable 1 }

MldCacheEntry ::= SEQUENCE {

   mldCacheAddress         InetAddressIPv6,
   mldCacheIfIndex            InterfaceIndex,
   mldCacheSelf               TruthValue,
   mldCacheLastReporter   InetAddressIPv6,
   mldCacheUpTime             TimeTicks,
   mldCacheExpiryTime         TimeTicks,
   mldCacheStatus             RowStatus

}

mldCacheAddress OBJECT-TYPE

   SYNTAX     InetAddressIPv6 (SIZE (16))
   MAX-ACCESS not-accessible
   STATUS     current
   DESCRIPTION
           "The IPv6 multicast group address for which this entry
           contains information."
   ::= { mldCacheEntry 1 }

mldCacheIfIndex OBJECT-TYPE

   SYNTAX     InterfaceIndex
   MAX-ACCESS not-accessible
   STATUS     current
   DESCRIPTION
            "The internetwork-layer interface for which this entry
            contains information for an IPv6 multicast group
            address."
   ::= { mldCacheEntry 2 }

mldCacheSelf OBJECT-TYPE

   SYNTAX     TruthValue
   MAX-ACCESS read-create
   STATUS     current
   DESCRIPTION
           "An indication of whether the local system is a member of
           this group address on this interface."
   DEFVAL     { true }
   ::= { mldCacheEntry 3 }

mldCacheLastReporter OBJECT-TYPE

   SYNTAX     InetAddressIPv6 (SIZE (16))
   MAX-ACCESS read-only
   STATUS     current
   DESCRIPTION
            "The IPv6 address of the source of the last membership
            report received for this IPv6 Multicast group address on
            this interface.  If no membership report has been
            received, this object has the value 0::0."
   ::= { mldCacheEntry 4 }

mldCacheUpTime OBJECT-TYPE

   SYNTAX     TimeTicks
   MAX-ACCESS read-only
   STATUS     current
   DESCRIPTION
           "The time elapsed since this entry was created."
   ::= { mldCacheEntry 5 }

mldCacheExpiryTime OBJECT-TYPE

   SYNTAX     TimeTicks
   MAX-ACCESS read-only
   STATUS     current
   DESCRIPTION
            "The minimum amount of time remaining before this entry
            will be aged out.  A value of 0 indicates that the entry
            is only present because mldCacheSelf is true and that if
            the router left the group, this entry would be aged out
            immediately.  Note that some implementations may process
            Membership Reports from the local system in the same way
            as reports from other hosts, so a value of 0 is not
            required."
   ::= { mldCacheEntry 6 }

mldCacheStatus OBJECT-TYPE

   SYNTAX     RowStatus
   MAX-ACCESS read-create
   STATUS     current
   DESCRIPTION
           "The status of this row, by which new entries may be
           created, or existing entries deleted from this table."
   ::= { mldCacheEntry 7 }

-- conformance information

mldMIBConformance

              OBJECT IDENTIFIER ::= { mldMIB 2 }

mldMIBCompliances

              OBJECT IDENTIFIER ::= { mldMIBConformance 1 }

mldMIBGroups

              OBJECT IDENTIFIER ::= { mldMIBConformance 2 }

-- compliance statements

mldHostMIBCompliance MODULE-COMPLIANCE

   STATUS  current
   DESCRIPTION
           "The compliance statement for hosts running MLD and
           implementing the MLD MIB."
   MODULE  -- this module
   MANDATORY-GROUPS { mldBaseMIBGroup,
                      mldHostMIBGroup
                    }
   OBJECT     mldInterfaceStatus
   MIN-ACCESS read-only
   DESCRIPTION
            "Write access is not required."
   ::= { mldMIBCompliances 1 }

mldRouterMIBCompliance MODULE-COMPLIANCE

   STATUS  current
   DESCRIPTION
           "The compliance statement for routers running MLD and
           implementing the MLD MIB."
   MODULE  -- this module
   MANDATORY-GROUPS { mldBaseMIBGroup,
                      mldRouterMIBGroup
                    }
   OBJECT     mldInterfaceStatus
   MIN-ACCESS read-only
   DESCRIPTION
            "Write access is not required."
   ::= { mldMIBCompliances 2 }

-- units of conformance

mldBaseMIBGroup OBJECT-GROUP

   OBJECTS { mldCacheSelf,
             mldCacheStatus, mldInterfaceStatus
           }
   STATUS  current
   DESCRIPTION
           "The basic collection of objects providing management of
           MLD.  The mldBaseMIBGroup is designed to allow for the
           manager creation and deletion of MLD cache entries."
   ::= { mldMIBGroups 1 }

mldRouterMIBGroup OBJECT-GROUP

   OBJECTS { mldCacheUpTime, mldCacheExpiryTime,
             mldInterfaceQueryInterval,
             mldInterfaceJoins, mldInterfaceGroups,
             mldCacheLastReporter,
             mldInterfaceQuerierUpTime,
             mldInterfaceQuerierExpiryTime,
             mldInterfaceQuerier,
             mldInterfaceVersion,
             mldInterfaceQueryMaxResponseDelay,
             mldInterfaceRobustness,
             mldInterfaceLastListenQueryIntvl
           }
   STATUS  current
   DESCRIPTION
           "A collection of additional objects for management of MLD
           in routers."
   ::= { mldMIBGroups 2 }

mldHostMIBGroup OBJECT-GROUP

   OBJECTS { mldInterfaceQuerier
           }
   STATUS  current
   DESCRIPTION
           "A collection of additional objects for management of MLD
           in hosts."
   ::= { mldMIBGroups 3 }

mldProxyMIBGroup OBJECT-GROUP

   OBJECTS { mldInterfaceProxyIfIndex }
   STATUS  current
   DESCRIPTION
           "A collection of additional objects for management of MLD
           proxy devices."
   ::= { mldMIBGroups 4 }

END

Security Considerations

This MIB contains readable objects whose values provide information related to multicast sessions. Some of these objects could contain sensitive information. In particular, the mldCacheSelf and mldCacheLastReporter could be used to identify machines which are listening to a given group address. There are also a number of objects that have a MAX-ACCESS clause of read-write and/or read- create, which allow an administrator to configure MLD in the router.

While unauthorized access to the readable objects is relatively innocuous, unauthorized access to the write-able objects could cause a denial of service. Hence, the support of SET operations in a non- secure environment without proper protection can have a negative effect on network operations.

SNMPv1 by itself is such an insecure environment. Even if the network itself is secure (for example by using IPSec), even then, there is no control as to who on the network is allowed to access and SET (change/create/delete) the objects in this MIB.

It is recommended that the implementers consider the security features as provided by the SNMPv3 framework. Specifically, the use of the User-based Security Model RFC 2574 RFC2574 and the View- based Access Control Model RFC 2575 RFC2575 is recommended.

It is then a customer/user responsibility to ensure that the SNMP entity giving access to this MIB, is properly configured to give access to those objects only to those principals (users) that have legitimate rights to access them.

Acknowledgements

This MIB module is based on the IGMP MIB authored by Keith McCloghrie, Dino Farinacci, and Dave Thaler. It was updated based on feedback from the IPNGWG working group, Bert Wijnen, Peder Norgaard, and extensive comments from Juergen Schoenwaelder.

References

RFC2710 Deering, S., Fenner, W. and B. Haberman, "Multicast

         Listener Discovery (MLD) for IPv6", RFC 2710, October 1999.

RFC2119 Bradner, S., "Key words for use in RFCs to Indicate

         Requirement Levels", BCP 14, RFC 2119, March 1997.

RFC2571 Harrington, D., Presuhn, R. and B. Wijnen, "An Architecture

         for Describing SNMP Management Frameworks", RFC 2571, April
         1999.

RFC1155 Rose, M. and K. McCloghrie, "Structure and Identification

         of Management Information for TCP/IP-based Internets", STD
         16, RFC 1155, May 1990.

RFC1212 Rose, M. and K. McCloghrie, "Concise MIB Definitions", STD

         16, RFC 1212, March 1991.

RFC1215 Rose, M., "A Convention for Defining Traps for use with the

         SNMP", RFC 1215, March 1991.

RFC2578 McCloghrie, K., Perkins, D., Schoenwaelder, J., Case, J.,

         Rose, M. and S. Waldbusser, "Structure of Management
         Information Version 2 (SMIv2)", STD 58, RFC 2578, April
         1999.

RFC2579 McCloghrie, K., Perkins, D., Schoenwaelder, J., Case, J.,

         Rose, M. and S. Waldbusser, "Textual Conventions for
         SMIv2", STD 58, RFC 2579, April 1999.

RFC2580 McCloghrie, K., Perkins, D., Schoenwaelder, J., Case, J.,

         Rose, M. and S. Waldbusser, "Conformance Statements for
         SMIv2", STD 58, RFC 2580, April 1999.

RFC1157 Case, J., Fedor, M., Schoffstall, M. and J. Davin, "Simple

         Network Management Protocol", STD 15, RFC 1157, May 1990.

RFC1901 Case, J., McCloghrie, K., Rose, M. and S. Waldbusser,

         "Introduction to Community-based SNMPv2", RFC 1901, January
         1996.

RFC1906 Case, J., McCloghrie, K., Rose, M. and S. Waldbusser,

         "Transport Mappings for Version 2 of the Simple Network
         Management Protocol (SNMPv2)", RFC 1906, January 1996.

RFC2572 Case, J., Harrington D., Presuhn R. and B. Wijnen, "Message

         Processing and Dispatching for the Simple Network
         Management Protocol (SNMP)", RFC 2572, April 1999.

RFC2574 Blumenthal, U. and B. Wijnen, "User-based Security Model

         (USM) for version 3 of the Simple Network Management
         Protocol (SNMPv3)", RFC 2574, April 1999.

RFC1905 Case, J., McCloghrie, K., Rose, M. and S. Waldbusser,

         "Protocol Operations for Version 2 of the Simple Network
         Management Protocol (SNMPv2)", RFC 1905, January 1996.

RFC2573 Levi, D., Meyer, P. and B. Stewart, "SNMPv3 Applications",

         RFC 2573, April 1999.

RFC2575 Wijnen, B., Presuhn, R. and K. McCloghrie, "View-based

         Access Control Model (VACM) for the Simple Network
         Management Protocol (SNMP)", RFC 2575, April 1999.

RFC2570 Case, J., Mundy, R., Partain, D. and B. Stewart,

         "Introduction to Version 3 of the Internet-standard Network
         Management Framework", RFC 2570, April 1999.

Authors' Addresses

Brian Haberman Nortel Networks 4309 Emperor Blvd. Suite 200 Durham, NC 27703 USA

Phone: +1-919-992-4439 EMail: [email protected]

Randy Worzella IBM Corporation 800 Park Office Drive Research Triangle Park, NC 27709 USA

Phone: +1-919-254-2202 EMail: [email protected]

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Acknowledgement

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