RFC 3019
IP Version 6 Management Information Base for The Multicast Listener Discovery Protocol
RFC 3019: IP Version 6 Management Information Base for The Multicast Listener Discovery Protocol ✨
okay bestie, this is part 1 of 3 🧚 so buckle up, more is coming 💅
Here's the title block tea 🫖 It's from the Network Working Group, it's RFC 3019, and it's dated January 2001. The authors are B. Haberman from Nortel Networks and R. Worzella from IBM 🎀 It's on the Standards Track 🔥 and the header has no Obsoletes or Updates line, so it doesn't replace or update any earlier RFC 🌸
Status of this Memo 💌
ok so this doc is an Internet standards track protocol spec for the Internet community, and it's literally asking for discussion and suggestions for improvements 🫶 For the standardization state and status, check the current edition of the "Internet Official Protocol Standards" (STD 1) 📚 And distribution of this memo is unlimited 🦋
Copyright Notice ©️
Copyright (C) The Internet Society (2001). All Rights Reserved.
Abstract ✨
so this doc defines a chunk of the Management Information Base (MIB) that network management protocols use in IPv6 internets 🌈 Specifically, it's the MIB module with managed objects for implementing 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] 🙈 these are the official BCP 14 words, so read them carefully bestie 💅
1. The SNMP Management Framework ✨
okay so the SNMP Management Framework is currently made 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 intro to the current SNMP Management Framework is in RFC 2570 [RFC2570] 📖
managed objects are accessed through a virtual information store called the Management Information Base or MIB 🧚 Objects in the MIB are defined using the mechanisms in the SMI ✨
this memo specifies a MIB module that is compliant to the SMIv2 💖 a MIB that conforms to SMIv1 can be produced through the right translations 🦋 The translated MIB must be semantically equivalent, except where objects or events are left out because no translation is possible (use of Counter64) 🙈 Some machine-readable info in SMIv2 gets turned into textual descriptions in SMIv1 during translation, but losing that machine-readable info is not considered to change the semantics of the MIB 🫶
2. Overview 🌸
this MIB module has two tables 👑
- The MLD Interface Table, which has one row for each interface where MLD is enabled.
- The MLD Cache Table, which has one row for each IPv6 Multicast group that has members on a particular interface.
both tables are meant to be implemented by hosts and routers 💅 Some objects in each table only apply to routers, so keep that in mind bestie 🌈
3. Definitions 🎀
here's the actual MIB module, served fresh 💅
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 }okay so the MIB keeps going, and the next bits are all about what the router can tell you about multicast groups 🦋
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 }Next up is the conformance stuff, which is basically the MIB's rulebook for who has to implement what 📋✨
-- 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 }
ENDSecurity Considerations ✨
okay this part is seriously important bestie, so read it carefully 🔒💀 this MIB has readable objects that show info about multicast sessions, and some of that info can be sensitive. the big ones are mldCacheSelf and mldCacheLastReporter</hotpink], which could be used to figure out which machines are listening to a particular group address 👀 and there are also a bunch of objects with a MAX-ACCESS of read-write and/or read-create, which let an admin configure MLD on the router 🛠️
reading the readable objects without permission is relatively innocuous, but changing the writable ones without permission could cause a denial of service 😭 so if you let SET operations happen in an insecure environment without proper protection, it can really mess with network operations 💔
SNMPv1 by itself is exactly that kind of insecure environment 🚨 and even if the network itself is secure (for example by using IPSec), there's still no control over who on the network is allowed to access and SET (change/create/delete) the objects in this MIB 🙃
so the recommendation is that implementers look at the security features that the SNMPv3 framework gives them 🧁 specifically, the User-based Security Model RFC 2574 [RFC2574] and the View-based Access Control Model RFC 2575 [RFC2575] are recommended 💜
and then it's a customer/user responsibility to make sure the SNMP entity giving access to this MIB is set up so only the principals (users) with legitimate rights can get to those objects 🫶 that part is on you, babe 💅
Acknowledgements 🫶
this MIB module is based on the IGMP MIB written by Keith McCloghrie, Dino Farinacci, and Dave Thaler 🌸 it got updated thanks to feedback from the IPNGWG working group, plus Bert Wijnen, Peder Norgaard, and some super extensive comments from Juergen Schoenwaelder 🙌✨
References ✨
Okay bestie, here's the reading list 📚 Every single source the spec leans on is here, in the original order, with all the details.
- [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 💌
Meet the people who wrote it 🫶 Here are their contact details, exactly as they appear in the original:
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.comFull Copyright Statement 💅
Legal time, but make it cute 🎀 This is the full copyright statement, kept complete and unchanged in substance.
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 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.
Acknowledgement 🫶
Last but not least, a shoutout to whoever keeps the lights on 🌈
Funding for the RFC Editor function is currently provided by the Internet Society. 💜
📦 where this page comes from
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