Table Of Contents

Configuring IGMP Snooping and MVR

Understanding and Configuring IGMP Snooping

Enabling or Disabling IGMP Snooping

CLI: Enabling or Disabling IGMP Snooping

Immediate-Leave Processing

CLI: Enabling IGMP Immediate-Leave Processing

Setting the Snooping Method

Joining a Multicast Group

Statically Configuring a Host to Join a Group

CLI: Statically Configuring a Interface to Join a Group

Leaving a Multicast Group

CLI: Configuring a Multicast Router Port

Understanding Multicast VLAN Registration

Using MVR in a Multicast Television Application

Configuration Guidelines and Limitations

Default MVR Configuration

Configuring MVR Global Parameters

Configuring MVR Interfaces

Displaying MVR

Configuring IGMP Snooping and MVR

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This chapter describes how to configure Internet Group Management Protocol (IGMP) snooping on your switch, including an application of local IGMP snooping, Multicast VLAN Registration (MVR).

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Note For complete syntax and usage information for the commands used in this chapter, refer to the Catalyst 2950 Desktop Switch Command Reference for this release and the Cisco IOS Release Network Protocols Command Reference, Part 1, for Release 12.1.

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This chapter consists of these sections:

•Understanding and Configuring IGMP Snooping

•Understanding Multicast VLAN Registration

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Note For MAC addresses that map to IP multicast groups, you can either manage them through features such as IGMP snooping and MVR, or you can use static MAC addresses. However, you cannot use both methods simultaneously. Therefore, before using IGMP snooping or MVR, you should remove all statically configured MAC addresses that map to IP multicast groups.

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Understanding and Configuring IGMP Snooping

Internet Group Management Protocol (IGMP) snooping constrains the flooding of multicast traffic by dynamically configuring the interfaces so that multicast traffic is forwarded only to those interfaces associated with IP multicast devices. The LAN switch snoops on the IGMP traffic between the host and the router and keeps track of multicast groups and member ports. When the switch receives an IGMP join report from a host for a particular multicast group, the switch adds the host port number to the associated multicast forwarding table entry. When it receives an IGMP Leave Group message from a host, it removes the host port from the table entry. After it relays the IGMP queries from the multicast router, it deletes entries periodically if it does not receive any IGMP membership reports from the multicast clients.

When IGMP snooping is enabled, the multicast router sends out periodic IGMP general queries to all VLANs. The switch responds to the router queries with only one join request per MAC multicast group, and the switch creates one entry per VLAN in the Layer 2 forwarding table for each MAC group from which it receives an IGMP join request. All hosts interested in this multicast traffic send join requests and are added to the forwarding table entry.

Layer 2 multicast groups learned through IGMP snooping are dynamic. However, you can statically configure MAC multicast groups by using the ip igmp snooping vlan static command. If you specify group membership for a multicast group address statically, your setting supersedes any automatic manipulation by IGMP snooping. Multicast group membership lists can consist of both user-defined and IGMP snooping-learned settings.

Catalyst 2950 switches support a maximum of 255 IP multicast groups and support both IGMP version 1 and IGMP version 2.

If a port spanning-tree, a port group, or a VLAN ID change occurs, the IGMP snooping-learned multicast groups from this port on the VLAN are deleted.

In the IP multicast-source-only environment, the switch learns the IP multicast group from the IP multicast data stream and only forwards traffic to the multicast router ports.

Enabling or Disabling IGMP Snooping

By default, IGMP snooping is globally enabled on the switch. When globally enabled or disabled, it is also enabled or disabled in all existing VLAN interfaces. By default, IGMP snooping is enabled on all VLANs, but it can be enabled and disabled on a per-VLAN basis.

Global IGMP snooping overrides the per-VLAN IGMP snooping capability. If global snooping is disabled, you cannot enable VLAN snooping. If global snooping is enabled, you can enable or disable snooping on a VLAN basis.

CLI: Enabling or Disabling IGMP Snooping

Beginning in privileged EXEC mode, follow these steps to globally enable IGMP snooping on the switch:

	Command	Purpose
Step 1	configure terminal	Enter global configuration mode.
Step 2	ip igmp snooping	Globally enable IGMP snooping in all existing VLAN interfaces.
Step 3	end	Return to privileged EXEC mode.
Step 4	show ip igmp snooping	Display snooping configuration.
Step 5	copy running-config startup-config	(Optional) Save your configuration to the startup configuration.

To globally disable IGMP snooping on all VLAN interfaces, use the no ip igmp snooping global command.

Beginning in privileged EXEC mode, follow these steps to enable IGMP snooping on a VLAN interface:

	Command	Purpose
Step 1	configure terminal	Enter global configuration mode.
Step 2	ip igmp snooping vlan vlan-id	Enable IGMP snooping on the VLAN interface.
Step 3	end	Return to privileged EXEC mode.
Step 4	show ip igmp snooping [vlan vlan-id]	Display snooping configuration. (Optional) vlan-id is the number of the VLAN.
Step 5	copy running-config startup-config	(Optional) Save your configuration to the startup configuration.

To disable IGMP snooping on a VLAN interface, use the no ip igmp snooping vlan vlan-id global configuration command for the specified VLAN number (for example, vlan1).

For CLI procedures, refer to the Cisco IOS Release 12.1 documentation on Cisco.com for additional information and CLI procedures.

Immediate-Leave Processing

IGMP snooping Immediate-Leave processing allows the switch to remove an interface that sends a leave message from the forwarding table without first sending out MAC-based general queries to the interface. The VLAN interface is pruned from the multicast tree for the multicast group specified in the original leave message. Immediate-Leave processing ensures optimal bandwidth management for all hosts on a switched network, even when multiple multicast groups are in use simultaneously.

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Note You should use the Immediate-Leave processing feature only on VLANs where only one host is connected to each port. If Immediate-Leave is enabled on VLANs where more than one host is connected to a port, some hosts might be inadvertently dropped. Immediate Leave is supported only with IGMP version 2 hosts.

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CLI: Enabling IGMP Immediate-Leave Processing

When you enable IGMP Immediate-Leave processing, the switch immediately removes a port from the IP multicast group when it detects an IGMP version 2 leave message on that port. Immediate-Leave processing allows the switch to remove an interface that sends a leave message from the forwarding table without first sending out group-specific queries to the interface. You should use the Immediate-Leave feature only when there is only a single receiver present on every port in the VLAN.

Beginning in privileged EXEC mode, follow these steps to enable IGMP Immediate-Leave processing:

	Command	Purpose
Step 1	configure terminal	Enter global configuration mode.
Step 2	ip igmp snooping vlan vlan-id immediate-leave	Enable IGMP Immediate-Leave processing on the VLAN interface.
Step 3	end	Return to privileged EXEC mode.

To disable Immediate-Leave processing, follow Steps 1 and 2 to enter interface configuration mode, and use the no ip igmp snooping vlan vlan-id immediate-leave global configuration command.

For CLI procedures, refer to the Cisco IOS Release 12.1 documentation on Cisco.com for additional information and CLI procedures.

Setting the Snooping Method

Multicast-capable router ports are added to the forwarding table for every IP multicast entry. The switch learns of such ports through one of these methods:

•Snooping on PIM and DVMRP packets

•Listening to CGMP self-join packets from other routers

•Statically connecting to a multicast router port with the ip igmp snooping mrouter global configuration command

You can configure the switch to either snoop on Protocol Independent Multicast/Distance Vector Multicast Routing Protocol (PIM/DVMRP) packets or to listen to CGMP self-join packets. By default, the switch snoops on PIM/DVMRP packets on all VLANs. To learn of multicast router ports through only CGMP self-join packets, use the ip igmp snooping vlan vlan-id mrouter learn cgmp global configuration command. When this command is used, the router listens only to CGMP self-join packets and no other CGMP packets. To learn of multicast router ports through only PIM-DVMRP packets, use the ip igmp snooping vlan vlan-id mrouter learn pim-dvmrp interface command.

Joining a Multicast Group

When a host connected to the switch wants to join an IP multicast group, it sends an IGMP join message, specifying the IP multicast group it wants to join. When the switch receives this message, it adds the port to the IP multicast group port address entry in the forwarding table.

Refer to Figure 11-1. Host 1 wants to join multicast group 224.1.2.3 and multicasts an unsolicited IGMP membership report (IGMP join message) to the group with the equivalent MAC destination address of 0100.5E01.0203. The switch recognizes IGMP packets and forwards them to the CPU. When the CPU receives the IGMP report multicast by Host 1, the CPU uses the information to set up a multicast forwarding table entry as shown in Table 11-1 that includes the port numbers of Host 1 and the router.

Figure 11-1 Initial IGMP Join Message

Table 11-1 IP Multicast Forwarding Table

Destination Address	Type of Packet	Ports
0100.5e01.0203	!IGMP	1, 2

Note that the switch architecture allows the CPU to distinguish IGMP information packets from other packets for the multicast group. The switch recognizes the IGMP packets through its filter engine. This prevents the CPU from becoming overloaded with multicast frames.

The entry in the multicast forwarding table tells the switching engine to send frames addressed to the 0100.5E01.0203 multicast MAC address that are not IGMP packets (!IGMP) to the router and to the host that has joined the group.

If another host (for example, Host 4) sends an IGMP join message for the same group (Figure 11-2), the CPU receives that message and adds the port number of Host 4 to the multicast forwarding table as shown in Table 11-2.

Figure 11-2 Second Host Joining a Multicast Group

Table 11-2 Updated Multicast Forwarding Table

Destination Address	Type of Packet	Ports
0100.5e01.0203	!IGMP	1, 2, 5

Statically Configuring a Host to Join a Group

Ports normally join multicast groups through the IGMP report message, but you can also statically configure a host on an interface.

CLI: Statically Configuring a Interface to Join a Group

Beginning in privileged EXEC mode, follow these steps to add a port as a member of a multicast group:

	Command	Purpose
Step 1	configure terminal	Enter global configuration mode
Step 2	ip igmp snooping vlan vlan-id static mac-address interface interface-id	Statically configure a port as a member of a multicast group: •vlan-id is the multicast group VLAN ID. •mac-address is the group MAC address. •interface-id is the member port.
Step 3	end
Step 4	show mac-address-table multicast [vlan vlan-id] [user | igmp-snooping] [count]	Display MAC address table entries for a VLAN. •vlan-id (Optional) is the multicast group VLAN ID. •user displays only the user-configured multicast entries. •igmp-snooping displays entries learned via IGMP snooping. •count displays only the total number of entries for the selected criteria, not the actual entries.
Step 5	copy running-config startup-config	(Optional) Save your configuration to the startup configuration.

For CLI procedures, refer to the Cisco IOS Release 12.1 documentation on Cisco.com for additional information and CLI procedures.

Leaving a Multicast Group

The router sends periodic IP multicast general queries, and the switch responds to these queries with one join response per MAC multicast group. As long as at least one host in the VLAN needs multicast traffic, the switch responds to the router queries, and the router continues forwarding the multicast traffic to the VLAN. The switch only forwards IP multicast group traffic to those hosts listed in the forwarding table for that IP multicast group.

When hosts need to leave a multicast group, they can either ignore the periodic general-query requests sent by the router, or they can send a leave message. When the switch receives a leave message from a host, it sends out a group-specific query to determine if any devices behind that interface are interested in traffic for the specific multicast group. If, after a number of queries, the router processor receives no reports from a VLAN, it removes the group for the VLAN from its multicast forwarding table.

CLI: Configuring a Multicast Router Port

Beginning in privileged EXEC mode, follow these steps to enable a static connection to a multicast router:

	Command	Purpose
Step 1	configure terminal	Enter global configuration mode.
Step 2	ip igmp snooping vlan vlan-id mrouter {interface interface-id} {learn {cgmp | pim-dvmrp}}	Specify the multicast router VLAN ID (1 to 1001). Specify the interface to the multicast router. Specify the multicast router learning method: •cgmp to specify listening for CGMP packets. •pim-dvmrp to specify snooping PIM-DVMRP packets
Step 3	end	Return to privileged EXEC mode.
Step 4	show ip igmp snooping [vlan vlan-id]	Verify that IGMP snooping is enabled on the VLAN interface.
Step 5	show ip igmp snooping mrouter [vlan vlan-id]	Display information on dynamically learned and manually configured multicast router interfaces.
Step 6	copy running-config startup-config	(Optional) Save your configuration to the startup configuration.

For CLI procedures, refer to the Cisco IOS Release 12.1 documentation on Cisco.com for additional information and CLI procedures.

Understanding Multicast VLAN Registration

Multicast VLAN Registration (MVR) is designed for applications using wide-scale deployment of multicast traffic across an Ethernet ring-based service provider network (for example, the broadcast of multiple television channels over a service-provider network). MVR allows a subscriber on a port to subscribe and unsubscribe to a multicast stream on the network-wide multicast VLAN. It allows the single multicast VLAN to be shared in the network while subscribers remain in separate VLANs. MVR provides the ability to continuously send multicast streams in the multicast VLAN, but to isolate the streams from the subscriber VLANs for bandwidth and security reasons.

MVR assumes that subscriber ports subscribe and unsubscribe (join and leave) these multicast streams by sending out IGMP join and leave messages. These messages can originate from an IGMP version-2-compatible host with an Ethernet connection. Although MVR operates on the underlying mechanism of IGMP snooping, the two features operate independently of each other. One can be enabled or disabled without affecting the behavior of the other feature. However, if IGMP snooping and MVR are both enabled, MVR only reacts to join and leave messages from multicast groups configured under MVR. Join and leave messages from all other multicast groups are managed by IGMP snooping.

The switch CPU identifies the MVR IP multicast streams and their associated MAC addresses in the switch forwarding table, intercepts the IGMP messages, and modifies the forwarding table to include or remove the subscriber as a receiver of the multicast stream, even though the receivers might be in a different VLAN from the source. This forwarding behavior selectively allows traffic to cross between different VLANs.

The Catalyst 2950 switch has dynamic and compatible modes of MVR operation:

•When operating in MVR dynamic mode, the switch performs standard IGMP snooping. IGMP information packets are sent to the switch CPU, but multicast data packets are not sent to the CPU. Dynamic mode allows the multicast router to run normally because the switch sends the IGMP join messages to the router, and the router only forwards multicast streams for a particular group to an interface if it has received a join message from the interface for the group. Receiver ports are treated as members of the multicast VLAN for MVR multicast control and data traffic. IGMP reports for MVR groups are sent out source ports in the multicast VLAN.

•When in MVR compatible mode, MVR interoperates with Catalyst 2900 XL and Catalyst 3500 XL switches. It works the same as dynamic mode for all multicast data packets and IGMP query and leave packets. However, received IGMP report packets for MVR groups are not sent out on the multicast VLAN source ports. In contrast to dynamic mode, the switch does not send join messages to the router. The router must be statically configured for the interface to receive the multicast stream. Therefore, in this mode, MVR does not support dynamic membership joins on source ports.

Using MVR in a Multicast Television Application

In a multicast television application, a PC or a television with a set-top box can receive the multicast stream. Multiple set-top boxes or PCs can be connected to one subscriber port, which is a switch port configured as an MVR receiver port. Refer to Figure 11-3. DHCP assigns an IP address to the set-top box or the PC. When a subscriber selects a channel, the set-top box or PC sends an IGMP report to the S1 switch to join the appropriate multicast. If the IGMP report matches one of the configured multicast MAC addresses, the switch CPU modifies the hardware address table to include this receiver port and VLAN as a forwarding destination of the specified multicast stream when it is received from the multicast VLAN. Uplink ports that send and receive multicast data to and from the multicast VLAN are called MVR source ports.

When a subscriber changes channels or turns off the television, the set-top box sends an IGMP leave message for the multicast stream. The switch CPU sends an IGMP group-specific query through the receiver port VLAN. If there is another set-top box in the VLAN still subscribing to this group, that set-top box must respond within the maximum response time. If the CPU does not receive a response, it eliminates the receiver port as a forwarding destination for this group.

If the Immediate-Leave feature is enabled on a receiver port, the port leaves a multicast group more quickly. Without Immediate Leave, when the switch receives an IGMP leave message from a subscriber on a receiver port, it sends out an IGMP query on that port and waits for IGMP group membership reports. If no reports are received in a configured time period, the receiver port is removed from multicast group membership. With Immediate Leave, an IGMP query is not sent from the receiver port on which the IGMP leave was received. As soon as the leave message is received, the receiver port is removed from multicast group membership, which speeds up leave latency. Only enable the Immediate Leave feature on receiver ports to which a single receiver device is connected.

Figure 11-3 Multicast VLAN Registration Example

MVR eliminates the need to duplicate television-channel multicast traffic for subscribers in each VLAN. Multicast traffic for all channels is sent only once around the VLAN trunk—only on the multicast VLAN. Although the IGMP leave and join messages originate with a subscriber, they appear to be initiated by a port in the multicast VLAN rather than in the VLAN to which the subscriber port is assigned. These messages dynamically register for streams of multicast traffic in the multicast VLAN on the Layer 3 device. The access layer switch (S1 switch) modifies the forwarding behavior to allow the traffic to be forwarded from the multicast VLAN to the subscriber port in a different VLAN, selectively allowing traffic to cross between two VLANs.

IGMP reports are sent to the same MAC addresses as the multicast data. The S1 CPU must capture all IGMP join and leave messages from receiver ports and forward them to the multicast VLAN of the source (uplink) port.

Configuration Guidelines and Limitations

Follow these guidelines when configuring MVR:

•Receiver ports cannot be trunk ports. Receiver ports on a switch can be in different VLANs, but should not belong to the multicast VLAN.

•The maximum number of multicast entries that can be configured on a switch (that is, the maximum number of television channels that can be received) is 256.

•Each channel is one multicast stream destined for a unique IP multicast address. These IP addresses cannot alias between themselves or with the reserved IP multicast addresses (in the range 224.0.0.xx).

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Note For complete syntax and usage information for the commands used in this section, refer to the Catalyst 2950 Desktop Switch Command Reference for this release.

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Default MVR Configuration

Table 11-3 shows the default MVR configuration.

Table 11-3 Default MVR Configuration

Feature	Default Setting
MVR	Disabled globally and per interface
Multicast addresses	None configured
Group IP address count	1
Query response time	0.5 second
Multicast VLAN	VLAN 1
Mode	Compatibility
Interface (per port) default	Neither a receiver or source port
Immediate Leave	Disabled on all ports

Configuring MVR Global Parameters

You do not need to set the optional MVR parameters if you choose to use the default settings. If you do want to change the default parameters (except for the MVR VLAN), you must first enable MVR.

Beginning in privileged EXEC mode, follow these steps to configure MVR parameters:

	Command	Purpose
Step 1	configure terminal	Enter global configuration mode.
Step 2	mvr	Enable MVR on the switch.
Step 3	mvr group ip-address [count]	Configure an IP multicast address on the switch or use the count parameter to configure a contiguous series of IP addresses. Any multicast data sent to this address is sent to all source ports on the switch and all receiver ports that have elected to receive data on that multicast address. Each multicast address corresponds to one television channel. Note Each IP address translates to a multicast 48-bit MAC address. If an IP address being configured translates (aliases) to a previously configured MAC address or to any reserved multicast MAC addresses, the command fails.
Step 4	mvr querytime value	(Optional) Define the maximum time to wait for IGMP report memberships on a receiver port before removing the port from multicast group membership. The value is in units of tenths of a second. The default is 5 tenths or one-half a second.
Step 5	mvr vlan vlan-id	(Optional) Specify the VLAN in which multicast data is received; all source ports must belong to this VLAN. The VLAN range is 1 to 1001. The default is VLAN 1.
Step 6	mvr mode {dynamic | compatible}	(Optional) Specify the MVR mode of operation: •dynamic allows dynamic MVR membership on source ports. •compatible provides for compatibility with Catalyst 2900 XL and Catalyst 3500 XL switches and does not support IGMP dynamic joins on source ports. The default is compatible mode.
Step 7	end	Exit configuration mode.
Step 8	show mvr show mvr members	Verify the configuration.
Step 9	copy running-config startup-config	(Optional) Save your entries in the configuration file.

This example shows how to enable MVR, configure the MVR group address, set the query time to 1 second (10 tenths), specify the MVR multicast VLAN as VLAN 22, set the MVR mode as dynamic, and verify the results:

Switch(config)# mvr

Switch(config)# mvr group 228.1.23.4

Switch(config)# mvr querytime 10

Switch(config)# mvr vlan 22 

Switch(config)# mvr mode dynamic 

Switch(config)# end 

Switch# show mvr

MVR Running: TRUE

MVR multicast vlan: 22

MVR Max Multicast Groups: 256

MVR Current multicast groups: 256

MVR Global query response time: 10 (tenths of sec)

MVR Mode: dynamic 

You can use the show mvr members privileged EXEC command to verify the MVR multicast group addresses on the switch.

Configuring MVR Interfaces

Beginning in privileged EXEC mode, follow these steps to configure MVR interfaces:

	Command	Purpose
Step 1	configure terminal	Enter global configuration mode.
Step 2	mvr	Enable MVR on the switch.
Step 3	interface interface-id	Enter interface configuration mode, and enter the type and number of the port to configure, for example, gi 0/1 or gigabitethernet 0/1 for Gigabit Ethernet port 1.
Step 4	mvr type {source | receiver}	Configure an MVR port as one of these: •source—Configure uplink ports that receive and send multicast data as source ports. Subscribers cannot be directly connected to source ports. All source ports on a switch belong to the single multicast VLAN. •receiver—Configure a port as a receiver port if it is a subscriber port and should only receive multicast data. It does not receive data unless it becomes a member of the multicast group, either statically or by using IGMP leave and join messages. Receiver ports cannot belong to the multicast VLAN.
Step 5	mvr vlan vlan-id group ip-address	(Optional) Statically configure a port to receive multicast traffic sent to the IP multicast address. A port statically configured as a member of a group remains a member of the group until statically removed. Note In compatible mode, this command applies only to receiver ports. In dynamic mode, it applies to receiver ports and source ports. Receiver ports can also dynamically join multicast groups by using IGMP join and leave messages.
Step 6	mvr immediate	(Optional) Enable the Immediate Leave feature of MVR on the port. Note This command applies only to receiver ports and should only be enabled on receiver ports to which a single receiver device is connected.
Step 7	end	Exit configuration mode.
Step 8	show mvr show mvr interface show mvr members	Verify the configuration.
Step 9	copy running-config startup-config	(Optional) Save your entries in the configuration file.

This example shows how to configure Gigabit Ethernet port 0/1 as a receiver port, statically configure the port to receive multicast traffic sent to the multicast group address, configure Immediate Leave on the interface, and verify the results:

Switch(config)# mvr

Switch(config)# interface gigabitethernet0/2

Switch(config-if)# mvr type receiver

Switch(config-if)# mvr vlan 22 group 228.1.23.4

Switch(config-if)# mvr immediate

Switch(config)# end 

Switch# show mvr interface gigabitethernet0/2

Type: RECEIVER Status: ACTIVE Immediate Leave: ENABLED 

This example shows the results of the show mvr interface privileged EXEC command when the member keyword is included:

Switch# show mvr interface gigabitethernet0/6 member

239.255.0.0     DYNAMIC ACTIVE

239.255.0.1     DYNAMIC ACTIVE

239.255.0.2     DYNAMIC ACTIVE

239.255.0.3     DYNAMIC ACTIVE

239.255.0.4     DYNAMIC ACTIVE

239.255.0.5     DYNAMIC ACTIVE

239.255.0.6     DYNAMIC ACTIVE

239.255.0.7     DYNAMIC ACTIVE

239.255.0.8     DYNAMIC ACTIVE

239.255.0.9     DYNAMIC ACTIVE

Displaying MVR

You can display MVR information for the switch or for a specified interfaces.

Beginning in privileged EXEC mode, use the commands in Table 11-3 to display MVR configuration:

Table 11-4 Commands for Displaying MVR Information

show mvr	Displays MVR status and values for the switch—whether MVR is enabled or disabled, the multicast VLAN, the number of multicast groups (always 256 for the Catalyst 2950 switch), the query response time, and the MVR mode.
show mvr interface [interface-id] [members [vlan vlan-id]]	Displays all MVR interfaces and their MVR configurations. When a specific interface is entered, displays this information: •Type—Receiver or Source •Status—One of these: –Active means that the port is part of a VLAN. –Up/Down means that the port is forwarding or nonforwarding. –Inactive means that the port is not part of any VLAN. •Immediate Leave—Enabled or Disabled If the members keyword is entered, displays all multicast group members on this port or, if a VLAN identification is entered, all multicast group members on the VLAN.
show mvr members [ip-address]	Displays all receiver ports that are members of any IP multicast group or the specified IP multicast group IP address.

This example shows the results of the show mvr privileged EXEC command:

Switch# show mvr

MVR Running: TRUE

MVR multicast vlan: 1

MVR Max Multicast Groups: 256

MVR Current multicast groups: 256

MVR Global query response time: 5 (tenths of sec)

MVR Mode: compatible 

This example shows the results of the show mvr interface privileged EXEC command:

Switch# show mvr interface

Port    Type            Status          Immediate Leave

----    ----            -------         ---------------

Gi0/1   SOURCE          ACTIVE/UP       DISABLED

Gi0/2   SOURCE          ACTIVE/UP       DISABLED

Gi0/3   RECEIVER        ACTIVE/UP       DISABLED

Gi0/4   RECEIVER        ACTIVE/UP       DISABLED

Gi0/5   RECEIVER        ACTIVE/UP       ENABLED

Gi0/6   RECEIVER        ACTIVE/UP       DISABLED

Gi0/7   RECEIVER        ACTIVE/UP       ENABLED

Gi0/8   RECEIVER        ACTIVE/UP       DISABLED

This example shows the results of the show mvr interface privileged EXEC command for a specified interface:

Switch# show mvr interface gigabitethernet0/2

Type: RECEIVER Status: ACTIVE Immediate Leave: DISABLED 

This example shows the results of the show mvr interface privileged EXEC command when the member keyword is included:

Switch# show mvr interface gigabitethernet0/1 member

239.255.0.0     DYNAMIC ACTIVE

239.255.0.1     DYNAMIC ACTIVE

239.255.0.2     DYNAMIC ACTIVE

239.255.0.3     DYNAMIC ACTIVE

239.255.0.4     DYNAMIC ACTIVE

239.255.0.5     DYNAMIC ACTIVE

239.255.0.6     DYNAMIC ACTIVE

239.255.0.7     DYNAMIC ACTIVE

239.255.0.8     DYNAMIC ACTIVE

239.255.0.9     DYNAMIC ACTIVE

This example shows the results of the show mvr member privileged EXEC command:

Switch# show mvr member

MVR Group IP    Status          Members

------------    ------          -------

239.255.0.1     ACTIVE          Gi0/1(d), Gi0/5(s)

239.255.0.2     INACTIVE        None

239.255.0.3     INACTIVE        None

239.255.0.4     INACTIVE        None

239.255.0.5     INACTIVE        None

239.255.0.6     INACTIVE        None

239.255.0.7     INACTIVE        None

239.255.0.8     INACTIVE        None

239.255.0.9     INACTIVE        None

239.255.0.10    INACTIVE        None

<output truncated>

239.255.0.255   INACTIVE        None

239.255.1.0     INACTIVE        None