IPV6-MLD-MIB

All MIBs › IPV6-MLD-MIB

Organization: IETF IPNGWG Working Group.

Last Updated: 2001-01-25

Category: IP and Core Protocols, Routing Protocols

Description: Defines managed objects for Multicast Listener Discovery (MLD), the IPv6 protocol used to manage multicast group membership on a link.

IPNetwork Monitor uses several OIDs from this MIB in network discovery and polling the applicable devices. Start monitoring IPV6-MLD-MIB with a free 30-day trial of IPNetwork Monitor.

What Is IPV6-MLD-MIB?

IPV6-MLD-MIB is a vendor-neutral IETF standards MIB defining managed objects for Multicast Listener Discovery (MLD), the IPv6 protocol routers use to learn which multicast groups have listeners on each attached link. It exposes per-interface MLD configuration and operational state, including query intervals, protocol version, querier election status, and counts of active joins and groups. Its monitoring value is squarely on software/protocol status: confirming MLD is operating correctly on each interface, that a querier is present, and that group membership counts match expectations, which is essential for diagnosing IPv6 multicast delivery problems. It is a companion to the base IPv6 and interface MIBs (referencing ifIndex from IF-MIB) and is analogous to IGMP monitoring in IPv4 networks. Deployment context is any IPv6-enabled router or Layer 3 switch running multicast applications such as IPTV or multicast-based service discovery. Engineers implementing or auditing this functionality typically reference the IPV6-MLD-MIB RFC/standard documentation for the authoritative specification.

IPNetwork Monitor allows you to monitor SNMP objects defined in IPV6-MLD-MIB. Use the built-in SNMP Monitoring Browser to explore available variables, view their current values and descriptions, and select the objects you want to monitor. You can then create SNMP monitors, configure thresholds, and receive alerts when monitored values change.

Supported Devices

vendor-neutral, standards-based MIB, not tied to a specific manufacturer
IPv6-enabled routers and Layer 3 switches

Monitoring Examples

An administrator would poll mldInterfaceTable/mldInterfaceEntry keyed by mldInterfaceIfIndex to check mldInterfaceQuerier and confirm exactly one querier is active per link, since a missing or duplicate querier disrupts group membership refresh. mldInterfaceJoins and mldInterfaceGroups reveal how many listeners and groups are currently active on an interface, useful for spotting an unexpected drop in multicast subscribers. mldInterfaceQueryInterval and mldInterfaceQueryMaxResponseDelay would be checked against configured values if group membership timers seem to be expiring too quickly, and mldInterfaceVersion confirms whether MLDv1 or MLDv2 is in use on that link.

What Can Be Monitored

MLD querier presence per interface
active multicast group joins
number of active multicast groups
MLD protocol version in use
query interval and max response delay

Imported Objects

From IF-MIB

InterfaceIndex
InterfaceIndexOrZero

From INET-ADDRESS-MIB

InetAddressIPv6

From SNMPv2-CONF

MODULE-COMPLIANCE
OBJECT-GROUP

From SNMPv2-SMI

Counter32
Gauge32
MODULE-IDENTITY
OBJECT-TYPE
TimeTicks
Unsigned32
mib-2

From SNMPv2-TC

RowStatus
TruthValue

How to Use in IPNetwork Monitor

Example using mldInterfaceJoins OID:

Select a device implementing IPV6-MLD-MIB as the target host to create a monitor — the SNMP service should be up and running on it. Click New Monitor, then check SNMP Custom on the Favorites tab, click Next, and confirm the host. On the next page, click Select... to open the built-in SNMP MIB Browser and type mldInterfaceJoins into the Find box to locate it in the OID tree, selecting the specific row/instance you want to monitor since this is a table column, then select it and click OK. 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. On the monitor's Main parameters page you can set the target's SNMP port (default 161), credentials, polling interval, and other settings — see the SNMP Monitor help for details. On the State conditions and Alerting tabs, configure when the monitor should change state and trigger an alert; since this is a Counter32-type OID, Value bounds is the most useful condition here — trigger an alert if the counter increases sharply between polls relative to its normal baseline, since an unexpected spike often reflects a real change in traffic or activity. Click Finish to create the monitor; you can adjust any parameter later.

OIDs

OID symbolic	OID numeric	Type	Access	Description
mldMIB	1.3.6.1.2.1.91			The MIB module for MLD Management.
mldMIBObjects	1.3.6.1.2.1.91.1
mldInterfaceTable	1.3.6.1.2.1.91.1.1		not-accessible	The (conceptual) table listing the interfaces on which MLD is enabled.
mldInterfaceEntry	1.3.6.1.2.1.91.1.1.1		not-accessible	An entry (conceptual row) representing an interface on which MLD is enabled.
NUM mldInterfaceIfIndex	1.3.6.1.2.1.91.1.1.1.1	InterfaceIndex	not-accessible	The internetwork-layer interface value of the interface for which MLD is enabled.
U32 mldInterfaceQueryInterval	1.3.6.1.2.1.91.1.1.1.2	Unsigned32	read-create	The frequency at which MLD Host-Query packets are transmitted on this interface.
ROW mldInterfaceStatus	1.3.6.1.2.1.91.1.1.1.3	RowStatus	read-create	The activation of a row enables MLD on the interface. The destruction of a row disables MLD on the interface.
U32 mldInterfaceVersion	1.3.6.1.2.1.91.1.1.1.4	Unsigned32	read-create	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.
ADR mldInterfaceQuerier	1.3.6.1.2.1.91.1.1.1.5	InetAddressIPv6	read-only	The address of the MLD Querier on the IPv6 subnet to which this interface is attached.
U32 mldInterfaceQueryMaxResponseDelay	1.3.6.1.2.1.91.1.1.1.6	Unsigned32	read-create	The maximum query response time advertised in MLD queries on this interface.
C32 mldInterfaceJoinsEx	1.3.6.1.2.1.91.1.1.1.7	Counter32	read-only	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.
G32 mldInterfaceGroups	1.3.6.1.2.1.91.1.1.1.8	Gauge32	read-only	The current number of entries for this interface in the Cache Table.
U32 mldInterfaceRobustness	1.3.6.1.2.1.91.1.1.1.9	Unsigned32	read-create	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.
U32 mldInterfaceLastListenQueryIntvl	1.3.6.1.2.1.91.1.1.1.10	Unsigned32	read-create	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.
NUM mldInterfaceProxyIfIndex	1.3.6.1.2.1.91.1.1.1.11	InterfaceIndexOrZero	read-create	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.
TIK mldInterfaceQuerierUpTime	1.3.6.1.2.1.91.1.1.1.12	TimeTicks	read-only	The time since mldInterfaceQuerier was last changed.
TIK mldInterfaceQuerierExpiryTime	1.3.6.1.2.1.91.1.1.1.13	TimeTicks	read-only	The time remaining before the Other Querier Present Timer expires. If the local system is the querier, the value of this object is zero.
mldCacheTable	1.3.6.1.2.1.91.1.2		not-accessible	The (conceptual) table listing the IPv6 multicast groups for which there are members on a particular interface.
mldCacheEntry	1.3.6.1.2.1.91.1.2.1		not-accessible	An entry (conceptual row) in the mldCacheTable.
ADR mldCacheAddress	1.3.6.1.2.1.91.1.2.1.1	InetAddressIPv6	not-accessible	The IPv6 multicast group address for which this entry contains information.
NUM mldCacheIfIndex	1.3.6.1.2.1.91.1.2.1.2	InterfaceIndex	not-accessible	The internetwork-layer interface for which this entry contains information for an IPv6 multicast group address.
T/F mldCacheSelf	1.3.6.1.2.1.91.1.2.1.3	TruthValue	read-create	An indication of whether the local system is a member of this group address on this interface.
ADR mldCacheLastReporter	1.3.6.1.2.1.91.1.2.1.4	InetAddressIPv6	read-only	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.
TIK mldCacheUpTime	1.3.6.1.2.1.91.1.2.1.5	TimeTicks	read-only	The time elapsed since this entry was created.
TIK mldCacheExpiryTime	1.3.6.1.2.1.91.1.2.1.6	TimeTicks	read-only	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.
ROW mldCacheStatus	1.3.6.1.2.1.91.1.2.1.7	RowStatus	read-create	The status of this row, by which new entries may be created, or existing entries deleted from this table.
mldMIBConformance	1.3.6.1.2.1.91.2
mldMIBCompliances	1.3.6.1.2.1.91.2.1
mldHostMIBCompliance	1.3.6.1.2.1.91.2.1.1			The compliance statement for hosts running MLD and implementing the MLD MIB.
mldRouterMIBCompliance	1.3.6.1.2.1.91.2.1.2			The compliance statement for routers running MLD and implementing the MLD MIB.
mldMIBGroups	1.3.6.1.2.1.91.2.2
mldBaseMIBGroup	1.3.6.1.2.1.91.2.2.1			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.
mldRouterMIBGroup	1.3.6.1.2.1.91.2.2.2			A collection of additional objects for management of MLD in routers.
mldHostMIBGroup	1.3.6.1.2.1.91.2.2.3			A collection of additional objects for management of MLD in hosts.
mldProxyMIBGroup	1.3.6.1.2.1.91.2.2.4			A collection of additional objects for management of MLD proxy devices.

RFC description

Manages IPv6 Multicast Listener Discovery (MLD) protocol configuration and multicast group membership.

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