Network Working Group B. Haberman

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].

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,

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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:

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

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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.

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: [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

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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

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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

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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 }

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::= { 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

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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

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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 }

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-- 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

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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."

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::= { 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.

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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.

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[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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Full Copyright Statement

Copyright (C) The Internet Society (2001). 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
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English.

The limited permissions granted above are perpetual and will not be
revoked by the Internet Society or its successors or assigns.

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"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.

Acknowledgement

Funding for the RFC Editor function is currently provided by the
Internet Society.

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