Network Working Group
Request for Comments: 3019
Category: Standards Track

B. Haberman
Nortel Networks
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

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].

1. 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.

2. Overview

This MIB module contains two tables:

The MLD Interface Table, which contains one row for each interface on which MLD is enabled.

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.

3. 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: haberman@nortelnetworks.com"
       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: haberman@nortelnetworks.com
   
   Randy Worzella
   IBM Corporation
   800 Park Office Drive
   Research Triangle Park, NC  27709
   USA
   
   Phone: +1-919-254-2202
   EMail: worzella@us.ibm.com

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