Configuring MVR

This chapter describes how to configure Multicast VLAN registration (MVR) on Cisco Nexus 3600 platform switches.

This chapter includes the following sections:

About MVR

In a typical Layer 2 multi-VLAN network, subscribers to a multicast group can be on multiple VLANs. To maintain data isolation between these VLANs, the multicast stream on the source VLAN must be passed to a router, which replicates the stream on all subscriber VLANs, wasting upstream bandwidth.

Multicast VLAN registration (MVR) allows a Layer 2 switch to forward the multicast data from a source on a common assigned VLAN to the subscriber VLANs, conserving upstream bandwidth by bypassing the router. The switch forwards multicast data for MVR IP multicast streams only to MVR ports on which hosts have joined, either by IGMP reports or by MVR static configuration. The switch forwards IGMP reports received from MVR hosts only to the source port. For other traffic, VLAN isolation is preserved.

MVR requires at least one VLAN to be designated as the common VLAN to carry the multicast stream from the source. More than one such multicast VLAN (MVR VLAN) can be configured in the system, and you can configure a global default MVR VLAN as well as interface-specific default MVR VLANs. Each multicast group using MVR is assigned to an MVR VLAN.

MVR allows a subscriber on a port to subscribe and unsubscribe to a multicast stream on the MVR VLAN by sending IGMP join and leave messages. IGMP leave messages from an MVR group are handled according to the IGMP configuration of the VLAN on which the leave message is received. If IGMP fast leave is enabled on the VLAN, the port is removed immediately; otherwise, an IGMP query is sent to the group to determine whether other hosts are present on the port.

MVR Interoperation with Other Features

MVR and IGMP Snooping

Although MVR operates on the underlying mechanism of IGMP snooping, the two features operate independently of each other. One feature can be enabled or disabled without affecting the operation of the other feature. If IGMP snooping is disabled globally or on a VLAN and MVR is enabled on the VLAN, IGMP snooping is internally enabled on the VLAN. Joins received for MVR groups on non-MVR receiver ports or joins received for non-MVR groups on MVR receiver ports are processed by IGMP snooping.

MVR and vPCs

  • As with IGMP snooping, IGMP control messages received by virtual port channel (vPC) peer switches are exchanged between the peers, allowing synchronization of MVR group information.

  • MVR configuration must be consistent between the peers.

  • The no ip igmp snooping mrouter vpc-peer-link command applies to MVR. With this command, multicast traffic is not sent to a peer link for the source VLAN and receiver VLAN unless an orphan port is in the VLAN.

  • The show mvr member command shows the multicast group on the vPC peer switch. However, the vPC peer switch does not show the multicast groups if it does not receive the IGMP membership report of the groups.

MVR and vPCs

  • As with IGMP snooping, IGMP control messages received by virtual port channel (vPC) peer switches are exchanged between the peers, allowing synchronization of MVR group information.

  • MVR configuration must be consistent between the peers.

  • The no ip igmp snooping mrouter vpc-peer-link command applies to MVR. With this command, multicast traffic is not sent to a peer link for the source VLAN and receiver VLAN unless an orphan port is in the VLAN.

  • The show mvr member command shows the multicast group on the vPC peer switch. However, the vPC peer switch does not show the multicast groups if it does not receive the IGMP membership report of the groups.

Guidelines and Limitations for MVR

MVR has the following guidelines and limitations:

  • MVR is supported only on Layer 2 Ethernet ports, such as individual ports, port channels, and virtual Ethernet (vEth) ports.

  • MVR receiver ports can only be access ports; they cannot be trunk ports. MVR source ports can be either access or trunk ports.

  • MVR configuration on Flex Link ports is not supported.

  • Priority tagging is not supported on MVR receiver ports.

  • The total number of MVR VLANs cannot exceed 250.

Default Settings for MVR

Following table lists the default settings for MVR parameters.

Table 1. Default MVR Parameters

Parameter

Default

MVR

Disabled globally and per interface

Global MVR VLAN

None configured

Interface (per port)

Neither a receiver nor a source port

Configuring MVR

You can configure the MVR global and interface parameters to affect the operation of the MVR process.

Configuring MVR Global Parameters

You can globally enable MVR and various configuration parameters.

Procedure

  Command or Action Purpose

Step 1

configure terminal

Example:

switch# configure terminal
switch(config)#

Enters global configuration mode.

Step 2

[ no] mvr

Example:

switch(config)# mvr
switch(config-mvr)#

Globally enables MVR. The default is disabled.

Use the no form of the command to disable MVR.

Step 3

[no] mvr-vlan vlan-id

Example:

switch(config-mvr)# mvr-vlan 7

Specifies the global default MVR VLAN. The MVR VLAN is the source of the multicast message that subsequent receivers subscribe to. The range is from 1 to 4094.

Use the no form of the command to clear the MVR VLAN.

Step 4

[no] mvr-group addr [/mask] [count groups] [vlan vlan-id]

Example:

switch(config-mvr)# mvr-group 230.1.1.1
count 4

Adds a multicast group at the specified IPv4 address (and optional netmask length) to the global default MVR VLAN. You can repeat this command to add additional groups to the MVR VLAN.

The IP address is entered in the format a.b.c.d/m, where m is the number of bits in the netmask, from 1 to 31.

You can optionally specify a number of MVR groups using contiguous multicast IP addresses starting with the specified IP address. Use the count keyword followed by a number from 1 to 64.

You can optionally specify an MVR VLAN for the group by using the vlan keyword. Otherwise, the group is assigned to the default MVR VLAN.

Use the no form of the command to clear the group configuration.

Step 5

(Optional) clear mvr counters [source-ports | receiver-ports]

Example:

switch(config-mvr)# clear mvr counters
 (Optional)

Clears MVR IGMP packet counters.

Step 6

(Optional) show mvr

Example:

switch(config-mvr)# show mvr
 (Optional)

Displays the global MVR configuration.

Step 7

(Optional) copy running-config startup-config

Example:

switch(config-mvr)# copy running-config startup-config
 (Optional)

Copies the running configuration to the startup configuration.

Configuring MVR Interfaces

You can configure MVR interfaces on your Cisco NX-OS device.

Procedure

  Command or Action Purpose

Step 1

configure terminal

Example:

switch# configure terminal
switch(config)#

Enters global configuration mode.

Step 2

mvr

Example:

switch(config)# mvr
switch(config-mvr)#

Globally enables MVR. The default is disabled.

Note

 

If MVR is enabled globally, this command is not required.

Step 3

interface {ethernet slot/port | port-channel channel-number | ethernet number}

Example:

switch(config-mvr)# interface
ethernet 2/2
switch(config-mvr-if)#

Specifies the Layer 2 port to configure and enters interface configuration mode.

Step 4

[no] mvr-type {source | receiver}

Example:

switch# configure terminal
switch(config)#

Configures an MVR port as one of these types of ports:

  • source—An uplink port that sends and receives multicast data is configured as an MVR source. The port automatically becomes a static receiver of MVR multicast groups. A source port should be a member of the MVR VLAN.

  • receiver—An access port that is connected to a host that wants to subscribe to an MVR multicast group is configured as an MVR receiver. A receiver port receives data only when it becomes a member of the multicast group by using IGMP leave and join messages.

If you attempt to configure a non-MVR port with MVR characteristics, the configuration is cached and does not take effect until the port becomes an MVR port. The default port mode is non-MVR.

Step 5

(Optional) [ no] mvr-vlan {vlan-id}

Example:

switch(config-mvr-if)# mvr-vlan 7
 (Optional)

Specifies an interface default MVR VLAN that overrides the global default MVR VLAN for joins received on the interface. The MVR VLAN is the source of the multicast message that subsequent receivers subscribe to. The range is from 1 to 4094.

Step 6

[ no] mvr-group addr [/mask] {vlan vlan-id}

Example:

switch(config-mvr-if)# mvr-group
225.1.3.1 vlan 100

Adds a multicast group at the specified IPv4 address (and optional netmask length) to the interface MVR VLAN, overriding the global MVR group configuration. You can repeat this command to add additional groups to the MVR.

The IP address is entered in the format a.b.c.d/m, where m is the number of bits in the netmask, from 1 to 31.

You can optionally specify an MVR VLAN for the group by using the vlan keyword; otherwise, the group is assigned to the interface default (if specified) or the global default MVR VLAN.

Use the no form of the command to clear the IPv4 address and netmask.

Step 7

copy running-config startup-config

Example:

switch(config-mvr-if)# copy running-config startup-config

Copies the running configuration to the startup configuration.

Verifying the MVR Configuration

To display the MVR configuration information, perform one of the following tasks:

Command

Purpose

show mvr

Displays the MVR subsystem configuration and status.

show mvr groups

Displays the MVR group configuration.

show ip igmp snooping [ vlan vlan-id ]

Displays information about IGMP snooping on the specified VLAN.

show mvr interface {ethernet slot/port | port-channel number}

Displays the MVR configuration on the specified interface.

show mvr members [ count ]

Displays the number and details of all MVR receiver members.

show mvr members interface {ethernet slot/port | port-channel number}

Displays details of MVR members on the specified interface.

show mvr members vlan vlan-id

Displays details of MVR members on the specified VLAN.

show mvr receiver-ports [ethernet slot/port | port-channel number]

Displays all MVR receiver ports on all interfaces or on the specified interface.

show mvr source-ports [ethernet slot/port | port-channel number]

Displays all MVR source ports on all interfaces or on the specified interface.

This example shows how to verify the MVR parameters:

switch# show mvr
MVR Status : enabled
Global MVR VLAN : 100
Number of MVR VLANs : 4

This example shows how to verify the MVR group configuration:

switch# show mvr groups
* - Global default MVR VLAN.
Group start Group end Count MVR-VLAN Interface
Mask
------------- --------------- ------ -------- -----------
228.1.2.240 228.1.2.255 /28 101
230.1.1.1 230.1.1.4 4 *100
235.1.1.6 235.1.1.6 1 340
225.1.3.1 225.1.3.1 1 *100 Eth1/10

This example shows how to verify the MVR interface configuration and status:

switch# show mvr interface
Port VLAN Type Status MVR-VLAN
---- ---- ---- ------ --------
Po10 100 SOURCE ACTIVE 100-101
Po201 201 RECEIVER ACTIVE 100-101,340
Po202 202 RECEIVER ACTIVE 100-101,340
Po203 203 RECEIVER ACTIVE 100-101,340
Po204 204 RECEIVER INACTIVE 100-101,340
Po205 205 RECEIVER ACTIVE 100-101,340
Po206 206 RECEIVER ACTIVE 100-101,340
Po207 207 RECEIVER ACTIVE 100-101,340
Po208 208 RECEIVER ACTIVE 2000-2001
Eth1/9 340 SOURCE ACTIVE 340
Eth1/10 20 RECEIVER ACTIVE 100-101,340
Eth2/2 20 RECEIVER ACTIVE 100-101,340
Eth102/1/1 102 RECEIVER ACTIVE 100-101,340
Eth102/1/2 102 RECEIVER INACTIVE 100-101,340
Eth103/1/1 103 RECEIVER ACTIVE 100-101,340
Eth103/1/2 103 RECEIVER ACTIVE 100-101,340
Status INVALID indicates one of the following misconfiguration:
a) Interface is not a switchport.
b) MVR receiver is not in access.
c) MVR source is in fex-fabric mode.

This example shows how to display all MVR members:

switch# show mvr members
MVR-VLAN Group Address Status Members
-------- ------------- ------- -------
100 230.1.1.1 ACTIVE Po201 Po202 Po203 Po205 Po206
100 230.1.1.2 ACTIVE Po205 Po206 Po207 Po208
340 235.1.1.6 ACTIVE Eth102/1/1
101 225.1.3.1 ACTIVE Eth1/10 Eth2/2
101 228.1.2.241 ACTIVE Eth103/1/1 Eth103/1/2

This example shows how to display all MVR receiver ports on all interfaces:

switch# show mvr receiver-ports
Port MVR-VLAN Status Joins Leaves
(v1,v2,v3)
------------ -------- -------- ------------ ------------
Po201 100 ACTIVE 8 2
Po202 100 ACTIVE 8 2
Po203 100 ACTIVE 8 2
Po204 100 INACTIVE 0 0
Po205 100 ACTIVE 10 6
Po206 100 ACTIVE 10 6
Po207 100 ACTIVE 5 0
Po208 100 ACTIVE 6 0
Eth1/10 101 ACTIVE 12 2
Eth2/2 101 ACTIVE 12 2
Eth102/1/1 340 ACTIVE 16 15
Eth102/1/2 340 INACTIVE 16 16
Eth103/1/1 101 ACTIVE 33 0
Eth103/1/2 101 ACTIVE 33 0

This example shows how to display all MVR source ports on all interfaces:

switch# show mvr source-ports
Port MVR-VLAN Status
------------ -------- --------
Po10 100 ACTIVE
Eth1/9 340 ACTIVE

Configuration Examples for MVR

The following example shows how to globally enable MVR and configure the global parameters:

switch# configure terminal
switch(config)# mvr
switch(config-mvr)# mvr-vlan 100
switch(config-mvr)# mvr-group 230.1.1.1 count 4
switch(config-mvr)# mvr-group 228.1.2.240/28 vlan 101
switch(config-mvr)# mvr-group 235.1.1.6 vlan 340
 
switch# show mvr
MVR Status : enabled
Global MVR VLAN : 100
Number of MVR VLANs : 3

The following example shows how to configure an Ethernet port as an MVR receiver port:

switch# configure terminal
switch(config)# mvr
switch(config-mvr)# interface ethernet 1/10
switch(config-mvr-if)# mvr-group 225.1.3.1 vlan 100
switch(config-mvr-if)# mvr-type receiver