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C through ip igmp
- clear ip cgmp
- clear ip msdp peer
- clear ip msdp sa-cache
- clear ip msdp statistics
- ip cgmp
- ip igmp access-group
- ip igmp helper-address
- ip igmp limit (global)
- ip igmp limit (interface)
- ip igmp mroute-proxy
- ip igmp proxy-service
- ip igmp snooping
- ip igmp snooping last-member-query-interval
- ip igmp snooping report-suppression
- ip igmp snooping vlan
- ip igmp snooping vlan immediate-leave
- ip igmp snooping vlan mrouter
- ip igmp snooping vlan static
- ip igmp static-group
- ip igmp unidirectional-link
- ip igmp version
clear ip cgmp
To clear all group entries from the caches of Catalyst switches, use the clear ip cgmp command in privileged EXEC mode.
Command History
Release
Modification
11.1
This command was introduced.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.2SX
This command is supported in the Cisco IOS Release 12.2SX train. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.
Usage Guidelines
This command sends a Cisco Group Management Protocol (CGMP) leave message with a group address of 0000.0000.0000 and a unicast address of 0000.0000.0000. This message instructs the switches to clear all group entries they have cached.
If an interface type and number are specified, the leave message is sent only on that interface. Otherwise, it is sent on all CGMP-enabled interfaces.
clear ip msdp peer
To clear the TCP connection to the specified Multicast Source Discovery Protocol (MSDP) peer, use the clear ip msdp peer command in privileged EXEC mode.
Command History
Release
Modification
12.0(7)T
This command was introduced.
12.0(23)S
The vrf keyword and vrf-name argument were added.
12.2(13)T
The vrf keyword and vrf-name argument were added.
12.2(14)S
This command was integrated into Cisco IOS Release 12.2(14)S.
12.2(18)SXE
Support for this command was introduced on the Supervisor Engine 720.
12.2(27)SBC
This command was integrated into Cisco IOS Release 12.2(27)SBC.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
Usage Guidelines
This command closes the TCP connection to the peer, resets all the MSDP peer statistics, and clears the input and output queues to and from the MSDP peer.
clear ip msdp sa-cache
To clear Multicast Source Discovery Protocol (MSDP) Source-Active (SA) cache entries, use the clear ip msdp sa-cache command in privileged EXEC mode.
Command History
Release
Modification
12.0(7)T
This command was introduced.
12.0(23)S
The vrf keyword and vrf-name argument were added.
12.2(13)T
The vrf keyword and vrf-name argument were added.
12.2(14)S
This command was integrated into Cisco IOS Release 12.2(14)S.
12.2(18)SXE
Support for this command was introduced on the Supervisor Engine 720.
12.2(27)SBC
This command was integrated into Cisco IOS Release 12.2(27)SBC.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
Usage Guidelines
In order to have any SA entries in the cache to clear, SA caching must have been enabled with the ip msdp cache-sa-state command.
If no multicast group is identified by group address or name, all SA cache entries are cleared.
clear ip msdp statistics
To clear statistics counters for one or all of the Multicast Source Discovery Protocol (MSDP) peers without resetting the sessions, use the clear ip msdp statistics command in privileged EXEC mode.
Command History
Release
Modification
12.0(7)T
This command was introduced.
12.0(23)S
The vrf keyword and vrf-name argument were added.
12.2(13)T
The vrf keyword and vrf-name argument were added.
12.2(14)S
This command was integrated into Cisco IOS Release 12.2(14)S.
12.2(18)SXE
Support for this command was introduced on the Supervisor Engine 720.
12.2(27)SBC
This command was integrated into Cisco IOS Release 12.2(27)SBC.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
ip cgmp
To enable Cisco Group Management Protocol (CGMP) on an interface of a router connected to a Cisco Catalyst switch, use the ip cgmp command in interface configuration mode. To disable CGMP routing, use the no form of this command.
Command History
Release
Modification
11.1
This command was introduced.
12.2
The router-only keyword was added.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.2SX
This command is supported in the Cisco IOS Release 12.2SX train. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.
Usage Guidelines
When enabled on an interface, this command triggers a CGMP join message. This command should be used only on 802 media (that is, Ethernet, FDDI, or Token Ring) or ATM. When a no ip cgmp command is issued, a triggered CGMP leave message is sent for the MAC address on the interface for group 0000.0000.0000 (all groups). CGMP can run on an interface only if Protocol Independent Multicast (PIM) is configured on the same interface.
A Cisco router will send CGMP join messages in response to receiving Internet Group Management Protocol (IGMP) reports from IGMP-capable members. Only the CGMP querier Cisco router sends these CGMP join messages on behalf of hosts.
The ip cgmp router-only command enables the routers in a VLAN to send only CGMP self-join and CGMP self-leave messages--no other types of CGMP messages will be sent. This feature allows other CGMP-capable routers to learn about multicast router ports. If the ip cgmp router-only command is not available on any of the external routers in the network, the ip cgmp command can be used instead. Issuing the ip cgmp command on a router enables that router to send CGMP self-join and CGMP self-leave messages as well as other types of CGMP messages.
When the proxy keyword is specified, the CGMP proxy function is also enabled. That is, any router that is not CGMP-capable will be advertised by the proxy router. The proxy router advertises the existence of other non-CGMP-capable routers by sending a CGMP join message with the MAC address of the non-CGMP-capable router and a group address of 0000.0000.0000.
Initially supported is Distance Vector Multicast Routing Protocol (DVMRP) proxying. If a DVMRP report is received from a router that is not a PIM router, a Cisco IGMP querier will advertise the MAC address of the DVMRP router in a CGMP join message with the group address 0000.0000.0000.
To perform CGMP proxy, a Cisco router must be the IGMP querier. If you configure the ip cgmp proxy command, you must manipulate the IP addresses so that a Cisco router will be the IGMP querier, which might be the highest or lowest IP address, depending on which version of IGMP is being run on the network. An IGMP Version 2 querier is selected based on the lowest IP addressed router on the interface. An IGMP Version 1 querier is selected based on the multicast routing protocol used on the interface.
When multiple Cisco routers are connected to a switched network and the ip cgmp proxy command is needed, we recommend that all routers be configured in the following manner:
- With the same CGMP option.
- To have precedence of becoming IGMP querier over non-Cisco routers.
ip igmp access-group
To restrict hosts (receivers) on a subnet to joining only multicast groups that are permitted by a standard IP access list or to restrict hosts (receivers) on a subnet to membership to only the (S,G) channels that are permitted by an extended IP access list, use the ip igmp access-group command in interface configuration mode. To disable this control, use the no form of this command.
Command History
Release
Modification
10.0
This command was introduced.
12.3(7)T
Extended access list support was added.
12.2(25)S
This command was integrated into Cisco IOS Release 12.2(25)S.
12.2(27)SBC
This command was integrated into Cisco IOS Release 12.2(27)SBC.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.2(33)SXH
This command was integrated into Cisco IOS Release 12.2(33)SXH.
Cisco IOS XE Release 3.2S
This command was modified. Support was added for this command in virtual network interface configuration mode.
Usage Guidelines
Use the ip igmp access-group command to filter groups from Internet Group Management Protocol (IGMP) reports by use of a standard access list or to filter sources and groups from IGMPv3 reports by use of an extended access list. This command is used to restrict hosts on a subnet to joining only multicast groups that are permitted by a standard IP access list or to restrict hosts on a subnet to membership to only those (S, G) channels that are permitted by an extended IP access list.
IGMP Version 3 (IGMPv3) accommodates extended access lists, which allow you to leverage an important advantage of Source Specific Multicast (SSM) in IPv4, that of basing access on source IP address. Prior to this feature, an IGMP access list accepted only a standard access list, allowing membership reports to be filtered based only on multicast group addresses.
IGMPv3 allows multicast receivers not only to join to groups, but to groups including or excluding sources. For appropriate access control, it is therefore necessary to allow filtering of IGMPv3 messages not only by group addresses reported, but by group and source addresses. IGMP extended access lists introduce this functionality. Using SSM with an IGMP extended access list allows you to permit or deny source S and group G (S, G) in IGMPv3 reports, thereby filtering SSM traffic based on source address, group address, or both.
Source Addresses in IGMPv3 Reports for ASM Groups
Additionally, IGMP extended access lists can be used to permit or filter traffic based on (0.0.0.0, G); that is, (*, G), in IGMP reports that are non-SSM, such as Any Source Multicast (ASM).
NoteThe permit and deny statements equivalent to (*, G) are permit host 0.0.0.0 host group-address and deny host 0.0.0.0 host group group-address, respectively.
Filtering applies to IGMPv3 reports for both ASM and SSM groups, but it is most important for SSM groups because multicast routing ignores source addresses in IGMPv3 reports for ASM groups. Source addresses in IGMPv3 membership reports for ASM groups are stored in the IGMP cache (as displayed with the show ip igmp membership command), but PIM-based IP multicast routing considers only the ASM groups reported. Therefore, adding filtering for source addresses for ASM groups impacts only the IGMP cache for ASM groups.
How IGMP Checks an Extended Access List
When an IGMP extended access list is referenced in the ip igmp access-group command on an interface, the (S, G) pairs in the permit and deny statements of the extended access list are matched against the (S, G) pair of the IGMP reports received on the interface. The first part of the extended access list clause controls the source, and the second part of the extended access list clause controls the multicast group.
Specifically, if an IGMP report with (S1, S2...Sn, G) is received, first the group (0, G) is checked against the access list statements. If the group is denied, the entire IGMP report is denied. If the group is permitted, each individual (S, G) pair is checked against the access list. Denied sources are taken out of the IGMP report, thereby denying any sources that match the access list from sending to the group.
NoteThe convention (0, G) means (*, G), which is a wildcard source with a multicast group number.
Examples
The following example shows how to configure a standard access list to filter the groups that are available on an interface for receivers to join. In this example, Ethernet interface 1/3 is configured to restrict receivers from joining groups in the range 226.1.0.0 through 226.1.255.255. Receivers are permitted to join all other groups on Ethernet interface 1/3.
access-list 1 deny 226.1.0.0 0.0.255.255 access-list 1 permit any log ! interface ethernet 1/3 ip igmp access-group 1
NoteAccess lists are very flexible; there is a seemingly limitless combination of permit and deny statements one could use in an access list to filter multicast traffic. The examples in this section simply provide a few examples of how it can be done.
The following example shows how to deny all states for a group G. In this example, FastEthernet interface 0/0 is configured to filter all sources for SSM group 232.2.2.2 in IGMPv3 reports, which effectively denies this group.
ip access-list extended test1 deny igmp any host 232.2.2.2 permit igmp any any ! interface FastEthernet0/0 ip igmp access-group test1 !The following example shows how to deny all states for a source S. In this example, Ethernet interface 1/1 is configured to filter all groups for source 10.2.1.32 in IGMPv3 reports, which effectively denies this source.
ip access-list extended test2 deny igmp host 10.2.1.32 any permit igmp any any ! interface Ethernet1/1 ip igmp access-group test2The following example shows how to permit all states for a group G. In this example, Ethernet interface 1/1 is configured to accept all sources for SSM group 232.1.1.10 in IGMPv3 reports, which effectively accepts this group altogether.
ip access-list extended test3 permit igmp any host 232.1.1.10 ! interface Ethernet1/1 ip igmp access-group test3The following example shows how to permit all states for a source S. In this example, Ethernet interface 1/2 is configured to accept all groups for source 10.6.23.32 in IGMPv3 reports, which effectively accepts this source altogether.
! ip access-list extended test4 permit igmp host 10.6.23.32 any ! interface Ethernet1/2 ip igmp access-group test4 !The following example shows how to filter a particular source S for a group G. In this example, Ethernet interface 0/3 is configured to filter source 232.2.2.2 for SSM group 232.2.30.30 in IGMPv3 reports.
ip access-list extended test5 deny igmp host 10.4.4.4 host 232.2.30.30 permit igmp any any ! interface Ethernet0/3 ip igmp access-group test5ip igmp helper-address
To cause the system to forward all Internet Group Management Protocol ( IGMP) host reports and leave messages received on the interface to the specified IP address, use the ip igmp helper-addresscommand in interface configuration mode. To disable such forwarding, use the no form of this command.
Command History
Release
Modification
11.2 F
This command was introduced.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.2SX
This command is supported in the Cisco IOS Release 12.2SX train. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.
Cisco IOS XE Release 3.2S
This command was modified. Support was added for this command in virtual network interface configuration mode.
Usage Guidelines
This command and the ip pim neighbor-filter command together enable stub multicast routing. The IGMP host reports and leave messages are forwarded to the IP address specified. The reports are re-sent out the next hop interface toward the IP address, with the source address of that interface. This command enables a type of “dense-mode” join, allowing stub sites not participating in Protocol Independent Multicast (PIM) to indicate membership in IP multicast groups.
Examples
The following example enables stub multicast routing on Router A, which has an outgoing interface with IP address 10.0.0.1. Router B is a central router with an incoming interface with address 10.0.0.2. Access list 1 filters PIM messages from the source (stub Router A).
Examples
Router A Configuration
ip multicast-routing ip pim dense-mode ip igmp helper-address 10.0.0.2ip igmp limit (global)
To configure a global limit on the number of multicast route (mroute) states created as a result of Internet Group Management Protocol (IGMP) membership reports (IGMP joins), use the ip igmp limit command in global configuration mode. To remove the limit imposed by the global IGMP state limiter, use the no form of this command.
Command History
Release
Modification
12.2(14)S
This command was introduced.
12.2(15)T
This command was integrated into Cisco IOS Release 12.2(15)T.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.2SX
This command is supported in the Cisco IOS Release 12.2SX train. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.
Usage Guidelines
Use this command to configure a global limit on the number of mroute states created as a result of IGMP membership reports (IGMP joins). When configured globally, the limit is referred to as a global IGMP state limiter. Membership reports exceeding the configured limits are not entered into the IGMP cache. This command can be used to prevent DoS attacks.
NoteIGMP state limiters impose limits on the number of mroute states resulting from IGMP, IGMP v3lite, and URL Rendezvous Directory (URD) membership reports on a global or per interface basis.
Use the ip igmp limit (interface)command to configure a per interface limit on the number mroute states created as a result of IGMP membership reports (IGMP joins).
NoteWhen configuring IGMP state limiters, you can only configure one global limit on a router and one limit per interface.
The mechanics of IGMP state limiters are as follows:
- If only a global IGMP state limiter has been configured and the limit has not been reached, IGMP membership reports are honored. When the configured limit has been reached, subsequent IGMP membership reports are then ignored (dropped) and a warning message in one of the following formats is generated:
%IGMP-6-IGMP_GROUP_LIMIT: IGMP limit exceeded for <group (*, group address)> on <interface type number> by host <ip address>or
%IGMP-6-IGMP_CHANNEL_LIMIT: IGMP limit exceeded for <channel (source address, group address)> on <interface type number> by host <ip address>
- If only per interface IGMP state limiters are configured, then each limit is only counted against the interface on which it was configured.
- If both a global IGMP state limiter and per interface IGMP state limiters are configured, the limits configured for the per interface IGMP state limiters are still enforced but are constrained by the global limit.
- If an ACL has been configured and the group or channel in the IGMP membership report matches, then the state for the IGMP membership is counted against the global limit and not the interface limit.
- If no ACL has been configured, the per interface IGMP state limiter accounts for all IGMP membership reports that do not exceed the configured limit.
ip igmp limit (interface)
To configure a per interface limit on the number of multicast route (mroute) states created as a result of Internet Group Management Protocol (IGMP) membership reports (IGMP joins), use the ip igmp limit command in interface configuration mode. To remove the limit imposed by a per interface IGMP state limiter, use the no form of this command.
Syntax Description
Command History
Release
Modification
12.2(14)S
This command was introduced.
12.2(15)T
This command was integrated into Cisco IOS Release 12.2(15)T.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.2SX
This command is supported in the Cisco IOS Release 12.2SX train. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.
Cisco IOS XE Release 3.2S
This command was modified. Support was added for this command in virtual network interface configuration mode.
Usage Guidelines
Use this command to configure per interface limits on the number mroute states created as a result of IGMP membership reports (IGMP joins). When configured on an interface, the limit is referred to as a per interface IGMP state limiter . Membership reports exceeding the configured limits for the interface are not entered into the IGMP cache. This command can be used to prevent DoS attacks or to provide a multicast Call Admission Control (CAC) mechanism in network environments where all the multicast flows roughly utilize the same amount of bandwidth.
NoteIGMP state limiters impose limits on the number of mroute states resulting from IGMP, IGMP v3lite, and URD membership reports on a global or per interface basis.
For the required number argument, specify a limit on the number of IGMP membership reports that can be cached for the specified interface. The range is from 1 to 64000.
Use the optional except access-list keyword and argument to prevent groups or channels from being counted against the interface limit. A standard or an extended ACL can be specified.
- A standard ACL can be used to define the (*, G) state to be excluded from the limit on an interface.
- An extended ACLs can be used to define the (S, G) state to be excluded from the limit on an interface. An extended ACL also can be used to define the (*, G) state to be excluded from the limit on an interface, by specifying 0.0.0.0 for the source address and source wildcard--referred to as (0, G)--in the permit or deny statements that compose the extended access list.
Use the ip igmp limit (global)command to configure a global limit on the number of mroute states created as a result of IGMP membership reports (IGMP joins).
NoteWhen configuring IGMP state limiters, you can only configure one global limit on a router and one limit per interface.
The mechanics of IGMP state limiters are as follows:
- If only a global IGMP state limiter has been configured and the limit has not been reached, IGMP membership reports are honored. When the configured limit has been reached, subsequent IGMP membership reports are then ignored (dropped) and a warning message in one of the following formats is generated:
%IGMP-6-IGMP_GROUP_LIMIT: IGMP limit exceeded for <group (*, group address)> on <interface type number> by host <ip address>or
%IGMP-6-IGMP_CHANNEL_LIMIT: IGMP limit exceeded for <channel (source address, group address)> on <interface type number> by host <ip address>
- If only per interface IGMP state limiters are configured, then each limit is only counted against the interface on which it was configured.
- If both a global IGMP state limiter and per interface IGMP state limiters are configured, the limits configured for the per interface IGMP state limiters are still enforced but are constrained by the global limit.
- If an ACL has been configured and the group or channel in the IGMP membership report matches, then the state for the IGMP membership is counted against the global limit and not the interface limit.
- If no ACL has been configured, the per interface IGMP state limiter accounts for all IGMP membership reports that do not exceed the configured limit.
Examples
The following example shows how configure a per interface limiter that limits the number of mroute states created as result of IGMP membership reports on Gigabit Ethernet interface 0/1 to 100:
interface GigabitEthernet 0/1 ip igmp limit 100Related Commands
Command
Description
ip igmp limit (global)
Globally limits the number of IGMP states resulting from IGMP membership reports (IGMP joins).
show ip igmp groups
Displays the multicast groups with receivers that are directly connected to the router and that were learned through IGMP.
show ip igmp interface
Displays information about the status and configuration of IGMP and multicast routing on interfaces.
ip igmp mroute-proxy
To enable Internet Group Management Protocol (IGMP) report forwarding of proxied (*, G) multicast static route (mroute) entries, use the ip igmp mroute-proxy command in interface configuration mode. To disable this service, use the no form of this command.
ip igmp mroute-proxy interface-type interface-number
no ip igmp mroute-proxy interface-type interface-number
Command History
Release
Modification
12.1(5)T
This command was introduced.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.2SX
This command is supported in the Cisco IOS Release 12.2SX train. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.
Cisco IOS XE Release 3.2S
This command was modified. Support was added for this command in virtual network interface configuration mode.
Usage Guidelines
When used with the ip igmp proxy-service interface command, this command enables forwarding of IGMP reports to a proxy service interface for all (*, G) forwarding entries for this interface in the multicast forwarding table.
Examples
The following example shows how to configure the ip igmp mroute-proxy command on Ethernet interface 1 to request that IGMP reports be sent to loopback interface 0 for all groups in the mroute table that are forwarded to Ethernet interface 1. This example also shows how to configure the ip igmp proxy-service command on loopback interface 0 to enable the forwarding of IGMP reports out the interface for all groups on interfaces registered through the ip igmp mroute-proxy command.
interface loopback 0 ip address 10.7.1.1 255.255.255.0 ip pim dense-mode ip igmp helper-address udl ethernet 0 ip igmp proxy-service ! interface ethernet 0 ip address 10.2.1.1 255.255.255.0 ip pim dense-mode ip igmp unidirectional link ! interface ethernet 1 ip address 10.1.1.1 255.255.255.0 ip pim sparse-mode ip igmp mroute-proxy loopback 0ip igmp proxy-service
To enable the mroute proxy service, use the ip igmp proxy-service command in interface configuration mode. To disable forwarding, use the no form of this command.
Command History
Release
Modification
12.1(5)T
This command was introduced.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.2SX
This command is supported in the Cisco IOS Release 12.2SX train. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.
Cisco IOS XE Release 3.2S
This command was modified. Support was added for this command in virtual network interface configuration mode.
Usage Guidelines
Based on the Internet Group Management Protocol (IGMP) query interval, the router periodically checks the multicast static route (mroute) table for (*, G) forwarding entries that match interfaces configured with the ip igmp mroute-proxy command. Where there is a match, one IGMP report is created and received on this interface. The ip igmp proxy-servicecommand is intended to be used with the ip igmp helper-address (UDL) command, in which case the IGMP report would be forwarded to an upstream router.
Examples
The following example shows how to configure the ip igmp mroute-proxy command on Ethernet interface 1 to request that IGMP reports be sent to loopback interface 0 for all groups in the mroute table that are forwarded to Ethernet interface 1. This example also shows how to configure the ip igmp proxy-service command on loopback interface 0 to enable the forwarding of IGMP reports out the interface for all groups on interfaces registered through the ip igmp mroute-proxy command.
interface loopback 0 ip address 10.7.1.1 255.255.255.0 ip pim dense-mode ip igmp helper-address udl ethernet 0 ip igmp proxy-service ! interface ethernet 0 ip address 10.2.1.1 255.255.255.0 ip pim dense-mode ip igmp unidirectional link ! interface ethernet 1 ip address 10.1.1.1 255.255.255.0 ip pim sparse-mode ip igmp mroute-proxy loopback 0ip igmp snooping
To enable Internet Group Management Protocol (IGMP) snooping globally or on an interface, use the ip igmp snooping command in the global configuration mode, interface configuration, or bridge domain configuration mode. To disable IGMP snooping, use the no form of this command.
Command Modes
Global configuration (config)
Interface configuration (config-if)
Bridge domain configuration (config-bdomain)
Command History
Release
Modification
12.0(5.2)WC(1)
This command was introduced.
12.2(15)ZJ
This command was implemented on the following platforms: Cisco 2600 series, Cisco 3600 series, and Cisco 3700 series routers.
12.2(14)SX
Support for this command was implemented on the Supervisor Engine 720.
12.3(4)T
This command was integrated into Cisco IOS Release 12.3(4)T on the following platforms: Cisco 2600 series, Cisco 3600 series, and Cisco 3700 series routers.
12.2(17d)SXB
This command was implemented on the Supervisor Engine 2.
Cisco IOS XE Release 3.5S
This command was integrated into Cisco IOS XE Release 3.5S. Support for this command was added to the bridge domain configuration mode.
15.2(4)S
This command was integrated into Cisco IOS Release 15.2(4)S.
Usage Guidelines
When IGMP snooping is globally enabled, IGMP snooping is enabled on all existing VLAN interfaces. When IGMP snooping is globally disabled, IGMP snooping is disabled on all existing VLAN interfaces.
When IGMP snooping is globally disabled, IGMP snooping is disabled on all existing bridge domain interfaces. When IGMP snooping is globally enabled, IGMP snooping is enabled on all existing bridge domain interfaces unless IGMP snooping was also explicitly disabled on a specific bridge domain interface. When IGMP snooping is disabled globally and on a specific bridge domain interface, globally enabling IGMP snooping will not enable snooping on the bridge domain interface; it must be explicitly re-enabled on the bridge domain interface.
Use the show ip igmp snooping privileged EXEC command to verify your IGMP settings.
The configuration is saved in NVRAM.
For Cisco 7600 series routers: Before you can enable IGMP snooping for Cisco 7600 series routers, you must configure the VLAN interface for multicast routing.
Examples
The following examples show how to globally disable IGMP snooping and how to disable IGMP snooping on a specified bridge domain interface:
Router(config)# no ip igmp snooping Router(config)# exit Router# show running-config . . . no ip igmp snoopingRouter(config)# bridge-domain1 Router(config-bdomain)# no ip igmp snooping Router(config-bdomain)# end Router# show running-config . . . bridge-domain 1 no ip igmp snooping ! !The following example shows how to globally enable IGMP snooping after it was explicitly disabled:
Router(config)# ip igmp snoopingRelated Commands
Command
Description
ip igmp snooping fast-leave
Enables the IGMPv3-snooping fast-leave processing.
ip igmp snooping vlan
Enables IGMP snooping on a VLAN interface.
ip igmp snooping vlan immediate-leave
Enables IGMP Immediate-Leave processing.
ip igmp snooping vlan mrouter
Configures a Layer 2 port as a multicast router port.
ip igmp snooping vlan static
Configures a Layer 2 port as a member of a group.
show ip igmp snooping
Displays the IGMP snooping configuration.
ip igmp snooping last-member-query-interval
To configure the last member query interval for IGMP snooping, use the ip igmp snooping last-member-query-interval command in the interface configuration or bridge domain configuration mode. To return to the default settings, use the no form of this command.
Syntax Description
interval
Length of time, in milliseconds, after which the group record is deleted if no reports are received. The default is 1000. See the “Usage Guidelines” section for more information.
For interfaces, the range is from 100 to 999, in multiples of 100. If you enter an interval that is not a multiple of 100, the interval is rounded to the next lowest multiple of 100. For example, if you enter 999, the interval is rounded down to 900 milliseconds.
For bridge domain interfaces, the range is from 100 to 32767.
Command History
Release
Modification
12.2(14)SX
This command was introduced on the Supervisor Engine 720.
12.2(17d)SXB
This command was integrated into Release 12.2(17d)SXB.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
Cisco IOS XE Release 3.5S
This command was integrated into Cisco IOS XE Release 3.5S. Support for this command was added to the bridge domain configuration mode.
15.2(4)S
This command was integrated into Cisco IOS Release 15.2(4)S.
Usage Guidelines
When a multicast host leaves a group, the host sends an IGMP leave. To check if this host is the last to leave the group, an IGMP query is sent out when the leave is seen and a timer is started. If no reports are received before the timer expires, the group record is deleted.
Use the ip igmp snooping last-member-query-count command to specify how often an IGMP query is sent in response to receiving an IGMP leave message.
The interval is the actual time that the Cisco 7600 series router waits for a response for the group-specific query.
If you enter an interval that is not a multiple of 100, the interval is rounded to the next lowest multiple of 100. For example, if you enter 999, the interval is rounded down to 900 milliseconds.
If you enable IGMP fast-leave processing and you enter the no igmp snooping last-member-query-interval command, the interval is set to 0 seconds; fast-leave processing always assumes higher priority.
Even though the valid interval range is 100 to 1000 milliseconds, you cannot enter a value of 1000. If you want this value, you must enter the no ip igmp snooping last-member-query-interval command to return to the default value (1000 milliseconds).
Examples
This example shows how to configure the last-member-query-interval to 200 milliseconds:
Router(config-if)# ip igmp snooping last-member-query-interval 200ip igmp snooping report-suppression
To turn on IP IGMP snooping report suppression, use the ip igmp snooping report-suppression command in the global configuration, interface configuration, or bridge domain configuration mode. To turn off report suppression, use the no form of this command.
Command Modes
Global configuration (config)
Interface configuration (config-if)
Bridge domain configuration (config-bdomain)
Command History
Release
Modification
12.2(18)SXF
Support for this command was introduced on the Supervisor Engine 720.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
Cisco IOS XE Release 3.5S
This command was integrated into Cisco IOS XE Release 3.5S. Support for this command was added to the bridge domain configuration mode.
15.2(4)S
This command was integrated into Cisco IOS Release 15.2(4)S.
Usage Guidelines
Use this command to enable report supression for all host reports responding to a general query or for all host reports on an interface or a bridge domain.
When you enable report suppression for all host reports responding to a general query, IP IGMP snooping forwards the first report only and suppresses the remaining reports to constrain IGMP traffic to the multicast router.
ip igmp snooping vlan
To enable Internet Group Management Protocol (IGMP) snooping on a specific VLAN, use the ip igmp snooping vlancommand in global configuration mode. To disable IGMP snooping on a VLAN interface, use the no form of this command.
Command History
Release
Modification
12.0(5.2)WC(1)
This command was introduced.
12.2(15)ZJ
This command was implemented on the following platforms: Cisco 2600 series, Cisco 3600 series, and Cisco 3700 series routers.
12.3(4)T
This command was integrated into Cisco IOS Release 12.3(4)T on the following platforms: Cisco 2600 series, Cisco 3600 series, and Cisco 3700 series routers.
Usage Guidelines
This command automatically configures the VLAN if it is not already configured. The configuration is saved in NVRAM.
Examples
The following example shows how to enable IGMP snooping on VLAN 2:
Router(config)# ip igmp snooping vlan 2The following example shows how to disable IGMP snooping on VLAN 2:
Router(config)# no ip igmp snooping vlan 2Related Commands
Command
Description
ip igmp snooping
Globally enables IGMP snooping. IGMP snooping must be globally enabled in order to be enabled on a VLAN.
ip igmp snooping vlan immediate-leave
Enables IGMP Immediate-Leave processing.
ip igmp snooping vlan mrouter
Configures a Layer 2 port as a multicast router port.
ip igmp snooping vlan static
Configures a Layer 2 port as a member of a group.
show ip igmp snooping
Displays the IGMP snooping configuration.
ip igmp snooping vlan immediate-leave
To enable Internet Group Management Protocol (IGMP) Immediate-Leave processing on a VLAN interface, use the ip igmp snooping vlan immediate-leavecommand in global configuration mode. To disable Immediate-Leave processing on the VLAN interface, use the no form of this command.
Command History
Release
Modification
12.0(5.2)WC(1)
This command was introduced.
12.2(15)ZJ
This command was implemented on the following platforms: Cisco 2600 series, Cisco 3600 series, and Cisco 3700 series routers.
12.3(4)T
This command was integrated into Cisco IOS Release 12.3(4)T on the following platforms: Cisco 2600 series, Cisco 3600 series, and Cisco 3700 series routers.
Usage Guidelines
Use Immediate-Leave processing only when there is only one IP multicast receiver present on every port in the VLAN. The Immediate-Leave configuration is saved in NVRAM.
Immediate-Leave processing is supported only with IGMP version 2 hosts.
Examples
The following example shows how to enable IGMP Immediate-Leave processing on VLAN 1:
Router(config)# ip igmp snooping vlan 1 immediate-leaveThe following example shows how to disable IGMP Immediate-Leave processing on VLAN 1:
Router(config)# no ip igmp snooping vlan 1 immediate-leaveRelated Commands
Command
Description
ip igmp snooping
Globally enables IGMP snooping. IGMP snooping must be globally enabled in order to be enabled on a VLAN.
ip igmp snooping vlan mrouter
Configures a Layer 2 port as a multicast router port.
ip igmp snooping vlan static
Configures a Layer 2 port as a member of a group.
show ip igmp snooping
Displays the IGMP snooping configuration.
show mac-address-table multicast
Displays the Layer 2 multicast entries for a VLAN.
ip igmp snooping vlan mrouter
To add a multicast router port and to configure the multicast router learning method, use the ip igmp snooping vlan mroutercommand in global configuration mode. To remove the configuration, use the no form of this command.
ip igmp snooping vlan vlan-id mrouter { interface interface-id | learn pim-dvmrp }
no ip igmp snooping vlan vlan-id mrouter { interface interface-id | learn pim-dvmrp }
Syntax Description
vlan-id
Specifies the VLAN ID. The range is from 1 to 1001. Do not enter leading zeroes.
interface interface-id
Specifies the interface of the member port that is configured to a static router port.
learn pim-dvmrp
Specifies the multicast router snooping PIM-DVMRP packets multicast router learning method.
Command History
Release
Modification
12.0(5.2)WC(1)
This command was introduced.
12.2(15)ZJ
This command was implemented on the following platforms: Cisco 2600 series, Cisco 3600 series, and Cisco 3700 series routers.
12.3(4)T
This command was integrated into Cisco IOS Release 12.3(4)T on the following platforms: Cisco 2600 series, Cisco 3600 series, and Cisco 3700 series routers.
Usage Guidelines
The configured learning method is saved in NVRAM.
Static connections to multicast routers are supported only on switch ports.
Examples
The following example shows how to configure Fast Ethernet interface 0/6 as a multicast router port:
Router(config)# ip igmp snooping vlan 1 mrouter interface fastethernet0/6Related Commands
Command
Description
ip igmp snooping
Globally enables IGMP snooping. IGMP snooping must be globally enabled in order to be enabled on a VLAN.
ip igmp snooping vlan
Enables IGMP snooping on the VLAN interface.
ip igmp snooping vlan immediate-leave
Configures IGMP Immediate-Leave processing.
ip igmp snooping vlan static
Configures a Layer 2 port as a member of a group.
show ip igmp snooping mrouter
Displays the statically and dynamically learned multicast router ports.
ip igmp snooping vlan static
To add a Layer 2 port as a member of a multicast group, use the ip igmp snooping vlan staticcommand in global configuration mode. To remove the configuration, use the no form of this command.
ip igmp snooping vlan vlan-id static mac-address interface interface-id
no ip igmp snooping vlan vlan-id static mac-address interface interface-id
Command History
Release
Modification
12.0(5.2)WC(1)
This command was introduced.
12.2(15)ZJ
This command was implemented on the following platforms: Cisco 2600 series, Cisco 3600 series, and Cisco 3700 series routers.
12.3(4)T
This command was integrated into Cisco IOS Release 12.3(4)T on the following platforms: Cisco 2600 series, Cisco 3600 series, and Cisco 3700 series routers.
Usage Guidelines
This command is used to statically configure the IP multicast group member ports.
The static ports and groups are saved in NVRAM.
Static connections to multicast routers are supported only on switch ports.
Use the show mac-address-table multicastprivileged EXEC command to verify your Layer 2 multicast entries.
Examples
The following example shows how to statically configure a host on an interface:
Router(config)# ip igmp snooping vlan 1 static 0100.5e02.0203 interface fastethernet0/6 Configuring port FastEthernet 0/6 on group 0100.5e02.0203Related Commands
Command
Description
ip igmp snooping
Globally enables IGMP snooping. IGMP snooping must be globally enabled in order to be enabled on a VLAN.
ip igmp snooping vlan
Enables IGMP snooping on the VLAN interface.
ip igmp snooping vlan immediate-leave
Configures IGMP Immediate-Leave processing.
ip igmp snooping vlan mrouter
Configures a Layer 2 port as a multicast router port.
show mac-address-table multicast
Displays the Layer 2 multicast entries for a VLAN.
ip igmp static-group
To configure static group membership entries on an interface, use the ip igmp static-group command in interface configuration mode. To delete static group membership entries, use the no form of this command.
ip igmp static-group { * | group-address [ source { source-address | ssm-map } ] | class-map class-map-name }
no ip igmp static-group { * | group-address [ source { source-address | ssm-map } ] | class-map class-map-name }
Syntax Description
*
Places the interface into all created multicast route (mroute) entries.
group-address
IP multicast group address to configure as a static group member on the interface.
source
(Optional) Statically forwards a (S, G) channel out of the interface.
source-address
(Optional) IP address of a system where multicast data packets originate.
ssm-map
(Optional) Configures Source Specific Multicast (SSM) mapping to be used on the interface to determine the source associated with this group. The resulting (S, G) channels are statically forwarded.
class-map class-map-name
Attaches an Internet Group Management Protocol (IGMP) static group range class map to the interface.
Command History
Release
Modification
11.2
This command was introduced.
12.3(2)T
This command was modified. The ssm-map keyword was added.
12.2(18)S
This command was modified. The ssm-map keyword was added.
12.2(18)SXD3
This command was integrated into Cisco IOS Release 12.2(18)SXD3.
12.2(27)SBC
This command was integrated into Cisco IOS Release 12.2(27)SBC.
12.2(18)SXF5
This command was modified. The class-map keyword and class-map-name argument were added.
15.0(1)M
This command was modified. The class-map keyword and class-map-name argument were added.
12.2(33)SRE
This command was modified. The class-map keyword and class-map-name argument were added.
Cisco IOS XE Release 2.6
This command was integrated into Cisco IOS XE Release 2.6.
Cisco IOS XE Release 3.2S
This command was modified. Support was added for this command in virtual network interface configuration mode.
15.0(1)SY
This command was integrated into Cisco IOS Release 15.0(1)SY.
15.1(1)SG
This command was integrated into Cisco IOS Release 15.1(1)SG.
Cisco IOS XE Release 3.3SG
This command was integrated into Cisco IOS XE Release 3.3SG.
Usage Guidelines
Use the ip igmp static-group command to configure static group membership entries on an interface. When you configure this command, packets to the group are fast-switched out the interface, provided that packets were received on the correct reverse path forwarding (RPF) interface. Once configured, static group membership entries are added to the IGMP cache and mroute table.
Configuring the ip igmp static-group command is unlike configuring the ip igmp join-group command, which allows the router to join the multicast group. This configuration of the ip igmp static-group command would cause the upstream routers to maintain the multicast routing table information for that group, which would ensure that all the paths to that multicast group are active.
If you configure the ip igmp join-group command for the same group address as the ip igmp static-group command, the ip igmp join-group command takes precedence, and the group behaves like a locally joined group.
Use the ip igmp static-group command with the ssm-map keyword to configure static traffic forwarding with SSM mapping on the last hop router. Static traffic forwarding can be used in conjunction with SSM mapping to statically forward SSM traffic for certain groups. When static traffic forwarding with SSM mapping is configured, the last hop router uses Domain Name System (DNS)-based SSM mapping to determine the sources associated with a group. The resulting (S, G) channels are then statically forwarded.
Use the ip igmp static-group class-map command with the class-map keyword and class-map-name argument to attach an IGMP static group class map to an interface. Once attached, all groups entries that are defined in the class map become static members on the interface and are added to the IGMP cache and to the mroute table.
For Cisco IOS Release 15.1(1)T and later releases
The MFIB maintains a (*, G/m) entry that handles dense mode packets. When the first dense mode packet arrives on a router, it matches this (*, G/m) entry. The packet is punted to the route processor only if at least one of the following two conditions is met: The source of the packet is directly connected to this router or the interface on which the packet was received has at least one PIM neighbor. If neither of these conditions is met, the (*, G/m) entry in the MFIB drops the packet without punting it. If the interface of a last hop router does not have any PIM neighbors and does not have a receiver, configure the ip igmp static-group command with the * keyword before any receiver joins (before any (*, G) state is created on the router) to simulate the presence of a receiver for all multicast group addresses on the interface, causing the interface to be added to the olist of the mroute entry and preventing incoming last hop router traffic for a dense mode group on the interface from being dropped.
Examples
The following example shows how to configure group address 239.100.100.101 on Ethernet interface 0:
interface ethernet 0 ip igmp static-group 239.100.100.101The following example shows how to configure group address 239.1.2.1 to use SSM mapping for statically forwarded groups on Ethernet interface 0:
interface ethernet 0 ip igmp static-group 239.1.2.1 source ssm-mapThe following example shows how to attach an IGMP static group range class map named static1 to GigabitEthernet interface 1/1:
interface GigabitEthernet1/1 ip igmp static-group class-map static1Related Commands
Command
Description
class-map type multicast-flows
Enters multicast-flows class-map configuration mode to create or modify IGMP static group class maps.
ip igmp join-group
Causes the router to join a multicast group.
ip igmp ssm-map enable
Enables SSM mapping for groups in a configured SSM range.
ip igmp ssm-map query dns
Configures DNS-based SSM mapping.
ip igmp ssm-map static
Enables static SSM mapping.
ip pim ssm
Defines the SSM range of IP multicast addresses.
ip igmp unidirectional-link
To configure an interface to be unidirectional and enable it for Internet Group Management Protocol (IGMP) unidirectional link routing (UDLR), use the ip igmp unidirectional-linkcommand in interface configuration mode. To disable the unidirectional link (UDL), use the no form of this command.
Command History
Release
Modification
12.0(3)T
This command was introduced.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.2SX
This command is supported in the Cisco IOS Release 12.2SX train. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.
Cisco IOS XE Release 3.2S
This command was modified. Support was added for this command in virtual network interface configuration mode.
Usage Guidelines
One example of when you might configure this command is if you have traffic traveling via a satellite.
If you have a small number of receivers, another way to achieve UDLR is to configure a UDLR tunnel. See the descriptions of the tunnel udlr receive-only and tunnel udlr send-only commands.
Examples
The following example configures an upstream router with UDLR on serial interface 0:
ip multicast-routing ! ! Unidirectional link ! interface serial 0 description Unidirectional to downlink-rtr ip address 10.0.0.1 255.0.0.0 ip pim sparse-dense-mode ip igmp unidirectional-link no keepaliveRelated Commands
Command
Description
ip igmp helper-address (UDL)
Configures IGMP helpering as required for IGMP UDLR.
ip igmp mroute-proxy
Enables IGMP report forwarding of proxied (*, G) mroute entries.
ip igmp proxy-service
Enables the mroute proxy service.
ip multicast default-rpf-distance
Changes the distance given to the default RPF interface when configuring IGMP UDLR.
show ip igmp udlr
Displays UDLR information for directly connected multicast groups on interfaces that have a UDL helper address configured.
tunnel udlr receive-only
Configures a unidirectional, GRE tunnel to act as a back channel that can receive messages, when another interface is configured for UDLR to send messages.
tunnel udlr send-only
Configures a unidirectional, GRE tunnel to act as a back channel that can send messages, when another interface is configured for UDLR to receive messages.
ip igmp version
To configure which version of Internet Group Management Protocol (IGMP) the router uses, use the ip igmp versioncommand in interface configuration mode. To restore the default value, use the no form of this command.
Command History
Release
Modification
11.1
This command was introduced.
12.1(5)T
The 3keyword was added.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.2SX
This command is supported in the Cisco IOS Release 12.2SX train. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.
Cisco IOS XE Release 3.2S
This Bandwidth-Based Call Admission Control for IP Multicast command was modified. Support was added for this command in virtual network interface configuration mode.
15.0(1)SY
This command was integrated into Cisco IOS Release 15.0(1)SY.
15.1(1)SG
This command was integrated into Cisco IOS Release 15.1(1)SG.
Cisco IOS XE Release 3.3SG
This command was integrated into Cisco IOS XE Release 3.3SG.
Usage Guidelines
All routers on the subnet must support the same version. The router does not automatically detect Version 1 routers and switch to Version 1 as did earlier releases of the Cisco IOS software. Hosts can have any IGMP version (1, 2, or 3) and the router will correctly detect their presence and query them appropriately.
Some commands require IGMP Version 2 or 3, such as the ip igmp query-max-response-timeand ip igmp query-timeoutcommands.
Related Commands
Command
Description
ip igmp query-max-response-time
Configures the maximum response time advertised in IGMP queries.
ip igmp query-timeout
Configures the timeout time before the router takes over as the querier for the interface, after the previous querier has stopped querying.
show ip igmp groups
Displays the multicast groups that are directly connected to the router and that were learned through IGMP.
show ip igmp interface
Displays multicast-related information about an interface.
