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Configuring IGMP
Snooping and Multicast VLAN Registration
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Prerequisites for Configuring IGMP Snooping and MVR
Prerequisites for
IGMP Snooping
Observe these guidelines when
configuring the IGMP snooping querier:
Configure the VLAN in global
configuration mode.
Configure an IP address on
the VLAN interface. When enabled, the IGMP snooping querier uses the IP address
as the query source address.
If there is no IP address
configured on the VLAN interface, the IGMP snooping querier tries to use the
configured global IP address for the IGMP querier. If there is no global IP
address specified, the IGMP querier tries to use the VLAN
switch virtual interface (SVI) IP address (if
one exists). If there is no SVI IP address, the
switch uses the first available IP address
configured on the
switch. The first IP address available
appears in the output of the
show ip interface privileged EXEC command. The
IGMP snooping querier does not generate an IGMP general query if it cannot find
an available IP address on the
switch.
The IGMP snooping querier
supports IGMP Versions 1 and 2.
When administratively
enabled, the IGMP snooping querier moves to the nonquerier state if it detects
the presence of a multicast router in the network.
When it is administratively
enabled, the IGMP snooping querier moves to the operationally disabled state
under these conditions:
IGMP snooping is disabled in
the VLAN.
PIM is enabled on the SVI of
the corresponding VLAN.
Restrictions for Configuring IGMP Snooping and MVR
Restrictions for
IGMP Snooping
The following are
the restrictions for IGMP snooping:
The switch
supports IGMPv3 snooping based only on the destination multicast MAC address.
It does not support snooping based on the source MAC address or on proxy
reports.
IGMPv3 join and leave
messages are not supported on
switches running IGMP filtering or Multicast
VLAN registration (MVR).
IGMP report suppression is supported only when the
multicast query has IGMPv1 and IGMPv2 reports. This feature is not supported
when the query includes IGMPv3 reports.
The IGMP configurable leave time is only supported on hosts
running IGMP Version 2. IGMP version 2 is the default version for the
switch.
The actual leave latency in
the network is usually the configured leave time. However, the leave time might
vary around the configured time, depending on real-time CPU load conditions,
network delays and the amount of traffic sent through the interface.
The IGMP
throttling action restriction can be applied only to Layer 2 ports. You can use
ip igmp max-groups action replace interface
configuration command on a logical EtherChannel interface but cannot use it on
ports that belong to an EtherChannel port group.
When the maximum group
limitation is set to the default (no maximum), entering the
ip igmp max-groups
action {deny
| replace }
command has no effect.
If you configure the
throttling action and set the maximum group limitation after an interface has
added multicast entries to the forwarding table, the forwarding-table entries
are either aged out or removed, depending on the throttling action.
Restrictions for
MVR
The following are
restrictions for MVR:
Only Layer 2
ports participate in MVR. You must configure ports as MVR receiver ports.
Only one MVR
multicast VLAN per
switch or
switch stack is supported.
Receiver ports
can only be access ports; they 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 (MVR group addresses) that can be configured on a
switch (that is, the maximum number of
television channels that can be received) is 256.
MVR multicast
data received in the source VLAN and leaving from receiver ports has its
time-to-live (TTL) decremented by 1 in the
switch.
Because MVR on
the
switch uses IP multicast addresses instead of
MAC multicast addresses, alias IP multicast addresses are allowed on the
switch. However, if the
switch is interoperating with Catalyst 3550
or Catalyst 3500 XL
switches, you should not configure IP addresses
that alias between themselves or with the reserved IP multicast addresses (in
the range 224.0.0.xxx).
Do not configure
MVR on private VLAN ports.
MVR is not
supported when multicast routing is enabled on a
switch. If you enable multicast routing and a
multicast routing protocol while MVR is enabled, MVR is disabled, and you
receive a warning message. If you try to enable MVR while multicast routing and
a multicast routing protocol are enabled, the operation to enable MVR is
cancelled, and you receive an error message
MVR data
received on an MVR receiver port is not forwarded to MVR source ports.
MVR does not
support IGMPv3 messages.
Information About IGMP Snooping and MVR
IGMP Snooping
Layer 2
switches can use IGMP snooping to constrain the
flooding of multicast traffic by dynamically configuring Layer 2 interfaces so
that multicast traffic is forwarded to only those interfaces associated with IP
multicast devices. As the name implies, IGMP snooping requires the LAN
switch to snoop on the IGMP transmissions
between the host and the router and to keep track of multicast groups and
member ports. When the
switch receives an IGMP report from a host
for a particular multicast group, the
switch adds the host port number to the
forwarding table entry; when it receives an IGMP Leave Group message from a
host, it removes the host port from the table entry. It also periodically
deletes entries if it does not receive IGMP membership reports from the
multicast clients.
Note
For more information on IP
multicast and IGMP, see RFC 1112 and RFC 2236.
The multicast router
(which could
be a
switch with the IP services featureon the stack masterswitch) sends out periodic general
queries to all VLANs. All hosts interested in this multicast traffic send join
requests and are added to the forwarding table entry. The
switch creates one entry per VLAN in the IGMP
snooping IP multicast forwarding table for each group from which it receives an
IGMP join request.
The
switch supports IP multicast group-based
bridging, instead of MAC-addressed based groups. With multicast MAC
address-based groups, if an IP address being configured translates (aliases) to
a previously configured MAC address or to any reserved multicast MAC addresses
(in the range 224.0.0.xxx), the command fails. Because the
switch uses IP multicast groups, there are no
address aliasing issues.
The IP multicast groups
learned through IGMP snooping are dynamic. However, you can statically
configure multicast groups by using the
ip igmp snooping vlan
vlan-id static ip_addressinterface interface-id
global configuration 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.
You can configure an IGMP
snooping querier to support IGMP snooping in subnets without multicast
interfaces because the multicast traffic does not need to be routed.
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.
These sections describe IGMP snooping characteristics:
IGMP Versions
The
switch supports IGMP version 1, IGMP version
2, and IGMP version 3. These versions are interoperable on the
switch. For example, if IGMP snooping is
enabled and the querier's version is IGMPv2, and the
switch receives an IGMPv3 report from a host,
then the
switch can forward the IGMPv3 report to the
multicast router.
An IGMPv3
switch can receive messages from and forward
messages to a device running the Source Specific Multicast (SSM) feature.
Joining a Multicast Group
Figure 1. Initial IGMP Join
Message.
When a host connected to the
switch wants to join an IP multicast group
and it is an IGMP version 2 client, it sends an unsolicited IGMP join message,
specifying the IP multicast group to join. Alternatively, when the
switch receives a general query from the
router, it forwards the query to all ports in the VLAN. IGMP version 1 or
version 2 hosts wanting to join the multicast group respond by sending a join
message to the
switch. The
switch CPU creates a multicast
forwarding-table entry for the group if it is not already present. The CPU also
adds the interface where the join message was received to the forwarding-table
entry. The host associated with that interface receives multicast traffic for
that multicast group.
Router A sends a general query to the
switch, which forwards the query to ports 2
through 5, all of which are members of the same VLAN. Host 1 wants to join
multicast group 224.1.2.3 and multicasts an IGMP membership report (IGMP join
message) to the group. The
switch CPU uses the information in the IGMP
report to set up a forwarding-table entry that includes the port numbers
connected to Host 1 and to the router.
Table 1. IGMP Snooping Forwarding
Table
Destination Address
Type of Packet
Ports
224.1.2.3
IGMP
1, 2
The
switch hardware can distinguish IGMP
information packets from other packets for the multicast group. The information
in the table tells the switching engine to send frames addressed to the
224.1.2.3 multicast IP address that are not IGMP packets to the router and to
the host that has joined the group.
Figure 2. Second Host Joining a
Multicast Group. If another host
(for example, Host 4) sends an unsolicited IGMP join message for the same
group, the CPU receives that message and adds the port number of Host 4 to the
forwarding table. Because the forwarding table directs IGMP messages only to
the CPU, the message is not flooded to other ports on the
switch. Any known multicast traffic is
forwarded to the group and not to the CPU.
Table 2. Updated IGMP Snooping
Forwarding Table
Destination Address
Type of Packet
Ports
224.1.2.3
IGMP
1, 2, 5
Leaving a Multicast Group
The router sends periodic multicast general queries, and the switch forwards these queries through all ports in the VLAN. Interested hosts respond to the queries. If at least one host in the
VLAN wants to receive multicast traffic, the router continues forwarding the multicast traffic to the VLAN. The switch forwards multicast group traffic only to those hosts listed in the forwarding table for that IP multicast group maintained
by IGMP snooping.
When hosts want to leave a multicast group, they can silently leave, or they can send a leave message. When the switch receives a leave message from a host, it sends a group-specific query to learn if any other devices connected to that interface
are interested in traffic for the specific multicast group. The switch then updates the forwarding table for that MAC group so that only those hosts interested in receiving multicast traffic for
the group are listed in the forwarding table. If the router receives no reports from a VLAN, it removes the group for the
VLAN from its IGMP cache.
Immediate Leave
The
switch uses IGMP snooping Immediate Leave to
remove from the forwarding table an interface that sends a leave message
without the
switch sending group-specific 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
ensures optimal bandwidth management for all hosts on a switched network, even
when multiple multicast groups are simultaneously in use.
Immediate Leave is only
supported on IGMP version 2 hosts. IGMP version 2 is the default version for
the
switch.
Note
You should use the Immediate
Leave feature only on VLANs where a single 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 may be dropped inadvertently.
IGMP Configurable-Leave Timer
You can configure the time
that the
switch waits after sending a group-specific
query to determine if hosts are still interested in a specific multicast group.
The IGMP leave response time can be configured from 100 to 32767 milliseconds.
IGMP Report Suppression
Note
IGMP report suppression is supported only when the multicast query has IGMPv1 and IGMPv2 reports. This feature is not supported
when the query includes IGMPv3 reports.
The switch uses IGMP report suppression to forward only one IGMP report per multicast router query to multicast devices. When IGMP
report suppression is enabled (the default), the switch sends the first IGMP report from all hosts for a group to all the multicast routers. The switch does not send the remaining IGMP reports for the group to the multicast routers. This feature prevents duplicate reports
from being sent to the multicast devices.
If the multicast router query includes requests only for IGMPv1 and IGMPv2 reports, the switch forwards only the first IGMPv1 or IGMPv2 report from all hosts for a group to all the multicast routers.
If the multicast router query also includes requests for IGMPv3 reports, the switch forwards all IGMPv1, IGMPv2, and IGMPv3 reports for a group to the multicast devices.
If you disable IGMP report suppression, all IGMP reports are forwarded to the multicast routers.
IGMP Snooping and
Switch Stacks
IGMP snooping functions across the
switch stack; that is, IGMP control
information from one
switch is distributed to all
switches in the stack. Regardless of the stack
member through which IGMP multicast data enters the stack, the data reaches the
hosts that have registered for that group.
If a
switch in the stack fails or is removed from
the stack, only the members of the multicast group that are on that
switch will not receive the multicast data.
All other members of a multicast group on other
switches in the stack continue to receive
multicast data streams. However, multicast groups that are common for both
Layer 2 and Layer 3 (IP multicast routing) might take longer to converge if the
active
switch
is removed.
Default IGMP Snooping Configuration
This table displays
the default IGMP snooping configuration for the
switch.
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.
These sections describe MVR:
MVR and IGMP
Note
MVR can coexist with IGMP snooping on a
switch.
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 method 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 reacts only 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 IP multicast group 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.
Modes of Operation
You can set the switch for compatible or dynamic mode of MVR operation:
In compatible mode, multicast data received by MVR hosts is forwarded to all MVR data ports, regardless of MVR host membership
on those ports. The multicast data is forwarded only to those receiver ports that MVR hosts have joined, either by IGMP reports
or by MVR static configuration. IGMP reports received from MVR hosts are never forwarded from MVR data ports that were configured
in the switch.
In dynamic mode, multicast data received by MVR hosts on the switch is forwarded from only those MVR data and client ports that the MVR hosts have joined, either by IGMP reports or by MVR static
configuration. Any IGMP reports received from MVR hosts are also forwarded from all the MVR data ports in the host. This eliminates
using unnecessary bandwidth on MVR data port links, which occurs when the switch runs in compatible mode.
MVR and Switch
Stacks
Only one MVR multicast
VLAN per
switch or
switch stack is supported.
Receiver ports and source
ports can be on different
switches in a
switch stack. Multicast data sent on the
multicast VLAN is forwarded to all MVR receiver ports across the stack. When a
new
switch is added to a stack, by default it has
no receiver ports.
If a
switch fails or is removed from the stack,
only those receiver ports belonging to that
switch will not receive the multicast data.
All other receiver ports on other
switches continue to receive the multicast
data.
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.
Figure 3. Multicast VLAN Registration Example. The following is an example configuration.
In this example configuration, 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 Switch A to join the appropriate multicast. If the IGMP report matches one of
the configured IP multicast group 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 a MAC-based general 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 specified in the query. If the CPU does not
receive a response, it eliminates the receiver port as a forwarding destination for this group.
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. Enable the Immediate-Leave feature only on receiver ports to which a single receiver device is connected.
MVR eliminates the need to duplicate television-channel multicast traffic for subscribers in each VLAN. Multicast traffic
for all channels is only sent around the VLAN trunk once—only on the multicast VLAN. The IGMP leave and join messages are
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, Switch A, 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 IP multicast group address as the multicast data. The Switch A CPU must capture all IGMP
join and leave messages from receiver ports and forward them to the multicast VLAN of the source (uplink) port, based on the
MVR mode.
Default MVR Configuration
Table 4. Default MVR Configuration
Feature
Default Setting
MVR
Disabled globally and per interface
Multicast addresses
None configured
Query response time
0.5 second
Multicast VLAN
VLAN 1
Mode
Compatible
Interface (per port) default
Neither a receiver nor a source port
Immediate Leave
Disabled on all ports
IGMP Filtering and Throttling
In some environments, for
example, metropolitan or multiple-dwelling unit (MDU) installations, you might
want to control the set of multicast groups to which a user on a
switch port can belong. You can control the
distribution of multicast services, such as IP/TV, based on some type of
subscription or service plan. You might also want to limit the number of
multicast groups to which a user on a
switch port can belong.
With the IGMP filtering
feature, you can filter multicast joins on a per-port basis by configuring IP
multicast profiles and associating them with individual
switch ports. An IGMP profile can contain one
or more multicast groups and specifies whether access to the group is permitted
or denied. If an IGMP profile denying access to a multicast group is applied to
a
switch port, the IGMP join report requesting
the stream of IP multicast traffic is dropped, and the port is not allowed to
receive IP multicast traffic from that group. If the filtering action permits
access to the multicast group, the IGMP report from the port is forwarded for
normal processing. You can also set the maximum number of IGMP groups that a
Layer 2 interface can join.
IGMP filtering controls only
group-specific query and membership reports, including join and leave reports.
It does not control general IGMP queries. IGMP filtering has no relationship
with the function that directs the forwarding of IP multicast traffic. The
filtering feature operates in the same manner whether CGMP or MVR is used to
forward the multicast traffic.
IGMP filtering applies only
to the dynamic learning of IP multicast group addresses, not static
configuration.
With the IGMP throttling
feature, you can set the maximum number of IGMP groups that a Layer 2 interface
can join. If the maximum number of IGMP groups is set, the IGMP snooping
forwarding table contains the maximum number of entries, and the interface
receives an IGMP join report, you can configure an interface to drop the IGMP
report or to replace the randomly selected multicast entry with the received
IGMP report.
Note
IGMPv3 join and leave
messages are not supported on
switches running IGMP filtering.
Default IGMP Filtering and Throttling Configuration
This table displays
the default IGMP filtering and throttling configuration for the
switch.
Table 5. Default IGMP Filtering
Configuration
Feature
Default Setting
IGMP filters
None applied.
IGMP maximum number of IGMP
groups
No maximum set.
Note
When the maximum number of groups is in the
forwarding table, the default IGMP throttling action is to deny the IGMP
report.
IGMP profiles
None defined.
IGMP profile action
Deny the range addresses.
How to Configure IGMP Snooping and MVR
Enabling or Disabling IGMP Snooping on a
Switch
When IGMP snooping is
globally enabled or disabled, it is also enabled or disabled in all existing
VLAN interfaces. IGMP snooping is enabled on all VLANs by default, but can be
enabled and disabled on a per-VLAN basis.
Global IGMP snooping
overrides the VLAN IGMP snooping. If global snooping is disabled, you cannot
enable VLAN snooping. If global snooping is enabled, you can enable or disable
VLAN snooping.
Follow these steps
to globally enable IGMP snooping on the
switch:
Procedure
Command or Action
Purpose
Step 1
enable
Example:
Switch> enable
Enables
privileged EXEC mode. Enter your password if prompted.
Step 2
configure terminal
Example:
Switch# configure terminal
Enters the global
configuration mode.
Step 3
ip igmp
snooping
Example:
Switch(config)# ip igmp snooping
Globally enables
IGMP snooping in all existing VLAN interfaces.
Note
To globally
disable IGMP snooping on all VLAN interfaces, use the
no ip igmp snooping
global configuration command.
Step 4
end
Example:
Switch(config)# end
Returns to
privileged EXEC mode.
Step 5
copy running-config
startup-config
Example:
Switch# copy running-config startup-config
(Optional) Saves your entries
in the configuration file.
Enabling or Disabling IGMP Snooping on a VLAN Interface
Follow these steps to enable IGMP snooping on a VLAN interface:
Procedure
Command or Action
Purpose
Step 1
enable
Example:
Switch> enable
Enables
privileged EXEC mode. Enter your password if prompted.
Step 2
configure terminal
Example:
Switch# configure terminal
Enters the global
configuration mode.
Step 3
ip igmp snooping
vlan vlan-id
Example:
Switch(config)# ip igmp snooping vlan 7
Enables IGMP
snooping on the VLAN interface. The VLAN ID range is 1 to 1001 and 1006 to
4094.
IGMP snooping
must be globally enabled before you can enable VLAN snooping.
Note
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.
Step 4
end
Example:
Switch(config)# end
Returns to
privileged EXEC mode.
Step 5
copy running-config
startup-config
Example:
Switch# copy running-config startup-config
(Optional) Saves your entries
in the configuration file.
Setting the Snooping
Method
Multicast-capable
router ports are added to the forwarding table for every Layer 2 multicast
entry. The switch learns of the ports through one of these methods:
Snooping on IGMP
queries, Protocol-Independent Multicast (PIM) packets, and Distance Vector
Multicast Routing Protocol (DVMRP) packets.
Listening to Cisco Group
Management Protocol (CGMP) packets from other routers.
Statically
connecting to a multicast router port using the
ip igmp snooping
mrouter global configuration command.
You can configure
the switch either to snoop on IGMP queries and PIM/DVMRP packets or to listen
to CGMP self-join or proxy-join packets. By default, the switch snoops on
PIM/DVMRP packets on all VLANs. To learn of multicast router ports through only
CGMP packets, use the ip igmp snooping vlan
vlan-id mrouter learn cgmp global configuration command. When
this command is entered, the router listens to only CGMP self-join and CGMP
proxy-join packets and to 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 global configuration command.
If you want to use
CGMP as the learning method and no multicast routers in the VLAN are CGMP
proxy-enabled, you must enter the ip cgmp
router-only command to dynamically access the router.
Procedure
Command or Action
Purpose
Step 1
enable
Example:
Switch> enable
Enables
privileged EXEC mode. Enter your password if prompted.
Switch(config)# ip igmp snooping
vlan 1 mrouter learn cgmp
Specifies the
multicast router learning method:
cgmp —Listens for CGMP packets. This method is
useful for reducing control traffic.
pim-dvmrp —Snoops on IGMP queries and PIM-DVMRP
packets. This is the default.
Note
To return to
the default learning method, use the
no ip igmp snooping
vlan vlan-idmrouter
learn cgmp global configuration command.
Step 4
end
Example:
Switch(config)# end
Returns to
privileged EXEC mode.
Step 5
show ip igmp
snooping
Example:
Switch# show ip igmp snooping
Verifies the
configuration.
Step 6
copy running-config
startup-config
Example:
Switch# copy running-config startup-config
(Optional) Saves your entries
in the configuration file.
Configuring a Multicast Router Port
Perform these steps to add a
multicast router port (enable a static connection to a multicast router) on the
switch.
Note
Static connections to
multicast routers are supported only on
switch ports.
Procedure
Command or Action
Purpose
Step 1
enable
Example:
Switch> enable
Enables
privileged EXEC mode. Enter your password if prompted.
Step 2
configure terminal
Example:
Switch# configure terminal
Enters the global
configuration mode.
Step 3
ip igmp snooping
vlan vlan-idmrouter interface interface-id
Example:
Switch(config)# ip igmp snooping vlan 5 mrouter interface gigabitethernet1/0/1
Specifies the
multicast router VLAN ID and the interface to the multicast router.
The VLAN ID range
is 1 to 1001 and 1006 to 4094.
The interface can
be a physical interface or a port channel. The port-channel range is 1 to 128.
Note
To remove a
multicast router port from the VLAN, use the
no ip igmp snooping
vlan vlan-idmrouter
interface interface-idglobal configuration command.
Step 4
end
Example:
Switch(config)# end
Returns to
privileged EXEC mode.
Step 5
show ip igmp snooping
mrouter [vlan vlan-id]
Example:
Switch# show ip igmp snooping mrouter vlan 5
Verifies that IGMP
snooping is enabled on the VLAN interface.
Step 6
copy running-config
startup-config
Example:
Switch# copy running-config startup-config
(Optional) Saves your entries
in the configuration file.
Configuring a Host Statically to Join a Group
Hosts or Layer 2 ports
normally join multicast groups dynamically, but you can also statically
configure a host on an interface.
Follow these steps to add a Layer 2 port as a member of a multicast
group:
Procedure
Command or Action
Purpose
Step 1
enable
Example:
Switch> enable
Enables
privileged EXEC mode. Enter your password if prompted.
Step 2
configure terminal
Example:
Switch# configure terminal
Enters the global
configuration mode.
Step 3
ip igmp snooping
vlan vlan-idstatic ip_addressinterface interface-id
Example:
Switch(config)# ip igmp snooping vlan 105 static 230.0.0.1 interface gigabitethernet1/0/1
Statically
configures a Layer 2 port as a member of a multicast group:
vlan-id is the multicast group VLAN ID. The range
is 1 to 1001 and 1006 to 4094.
ip-address is the group IP address.
interface-id is the member port. It can be a
physical interface or a port channel (1 to 128).
Note
To remove the
Layer 2 port from the multicast group, use theno ip
igmp snooping vlan
vlan-idstatic mac-addressinterface interface-id global configuration command.
Step 4
end
Example:
Switch(config)# end
Returns to
privileged EXEC mode.
Step 5
show ip igmp
snooping groups
Example:
Switch# show ip igmp snooping groups
Verifies the
member port and the IP address.
Step 6
copy running-config
startup-config
Example:
Switch# copy running-config startup-config
(Optional) Saves your entries
in the configuration file.
Enabling IGMP Immediate Leave
When you enable IGMP
Immediate Leave, the
switch immediately removes a port when it
detects an IGMP Version 2 leave message on that port. You should use the
Immediate-Leave feature only when there is a single receiver present on every
port in the VLAN.
Note
Immediate Leave is supported
only on IGMP Version 2 hosts. IGMP Version 2 is the default version for the
switch.
Procedure
Command or Action
Purpose
Step 1
enable
Example:
Switch> enable
Enables
privileged EXEC mode. Enter your password if prompted.
Step 2
configure terminal
Example:
Switch# configure terminal
Enters the global
configuration mode.
Step 3
ip igmp snooping
vlan vlan-idimmediate-leave
Example:
Switch(config)# ip igmp snooping vlan 21 immediate-leave
Enables IGMP
Immediate Leave on the VLAN interface.
Note
To disable
IGMP Immediate Leave on a VLAN, use the no ip igmp snooping vlan vlan-idimmediate-leave global configuration command.
Step 4
end
Example:
Switch(config)# end
Returns to
privileged EXEC mode.
Step 5
show ip igmp
snooping vlan vlan-id
Example:
Switch# show ip igmp snooping vlan 21
Verifies that
Immediate Leave is enabled on the VLAN interface.
Step 6
end
Example:
Switch(config)# end
Returns to
privileged EXEC mode.
Configuring the IGMP Leave Timer
You can configure the leave time globally or on a per-VLAN basis.
Follow these steps to enable the IGMP configurable-leave timer:
Procedure
Command or Action
Purpose
Step 1
enable
Example:
Switch> enable
Enables
privileged EXEC mode. Enter your password if prompted.
Step 2
configure terminal
Example:
Switch# configure terminal
Enters the global
configuration mode.
Step 3
ip igmp snooping
last-member-query-interval time
Example:
Switch(config)# ip igmp snooping last-member-query-interval 1000
Configures the
IGMP leave timer globally. The range is 100 to 32767 milliseconds.
The default leave
time is 1000 milliseconds.
Note
To globally
reset the IGMP leave timer to the default setting, use the no ip igmp snooping last-member-query-interval
global configuration command.
Step 4
ip igmp snooping
vlan vlan-idlast-member-query-interval time
Example:
Switch(config)# ip igmp snooping vlan 210 last-member-query-interval 1000
(Optional)
Configures the IGMP leave time on the VLAN interface. The range is 100 to 32767
milliseconds.
Note
Configuring the
leave time on a VLAN overrides the globally configured timer.
Note
To remove the
configured IGMP leave-time setting from the specified VLAN, use the
no ip igmp snooping
vlan vlan-idlast-member-query-interval global configuration
command.
Step 5
end
Example:
Switch(config)# end
Returns to
privileged EXEC mode.
Step 6
show ip igmp
snooping
Example:
Switch# show ip igmp snooping
(Optional)
Displays the configured IGMP leave time.
Step 7
copy running-config
startup-config
Example:
Switch# copy running-config startup-config
(Optional) Saves your entries
in the configuration file.
Configuring TCN-Related Commands
Controlling the Multicast Flooding Time After a TCN Event
You can configure the number
of general queries by which multicast data traffic is flooded after a topology
change notification (TCN) event. If you set the TCN flood query count to 1 the
flooding stops after receiving 1 general query. If you set the count to 7, the
flooding continues until 7 general queries are received. Groups are relearned
based on the general queries received during the TCN event.
Some examples of TCN events
are when the client location is changed and the receiver is on same port that
was blocked but is now forwarding, and when a port goes down without sending a
leave message.
Follow these steps to configure the TCN flood query count:
Procedure
Command or Action
Purpose
Step 1
enable
Example:
Switch> enable
Enables
privileged EXEC mode. Enter your password if prompted.
Step 2
configure terminal
Example:
Switch# configure terminal
Enters the global
configuration mode.
Step 3
ip igmp snooping
tcn flood query count count
Example:
Switch(config)# ip igmp snooping tcn flood query count 3
Specifies the
number of IGMP general queries for which the multicast traffic is flooded.
The range is 1 to 10. The default, the flooding query count is 2.
Note
To return to
the default flooding query count, use the
no ip igmp snooping tcn flood
query count global configuration command.
Step 4
end
Example:
Switch(config)# end
Returns to
privileged EXEC mode.
Step 5
show ip igmp
snooping
Example:
Switch# show ip igmp snooping
Verifies the TCN
settings.
Step 6
copy running-config
startup-config
Example:
Switch# copy running-config startup-config
(Optional) Saves your entries
in the configuration file.
Recovering from Flood Mode
When a topology change occurs, the spanning-tree root sends a
special IGMP leave message (also known as global leave) with the group
multicast address 0.0.0.0. However, you can enable the
switch to send the global leave message
whether it is the spanning-tree root or not. When the router receives this
special leave, it immediately sends general queries, which expedite the process
of recovering from the flood mode during the TCN event. Leaves are always sent
if the
switch is the spanning-tree root regardless
of this configuration.
Follow these steps to enable sending of leave messages:
Procedure
Command or Action
Purpose
Step 1
enable
Example:
Switch> enable
Enables
privileged EXEC mode. Enter your password if prompted.
Step 2
configure terminal
Example:
Switch# configure terminal
Enters the global
configuration mode.
Step 3
ip igmp snooping
tcn query solicit
Example:
Switch(config)# ip igmp snooping tcn query solicit
Sends an IGMP
leave message (global leave) to speed the process of recovering from the flood
mode caused during a TCN event. By default, query solicitation is disabled.
Note
To return to
the default query solicitation, use the no ip igmp snooping tcn query solicit global
configuration command.
Step 4
end
Example:
Switch(config)# end
Returns to
privileged EXEC mode.
Step 5
show ip igmp
snooping
Example:
Switch# show ip igmp snooping
Verifies the TCN
settings.
Step 6
copy running-config
startup-config
Example:
Switch# copy running-config startup-config
(Optional) Saves your entries
in the configuration file.
Disabling Multicast Flooding During a TCN Event
When the
switch receives a TCN, multicast traffic is
flooded to all the ports until 2 general queries are received. If the
switch has many ports with attached hosts
that are subscribed to different multicast groups, this flooding might exceed
the capacity of the link and cause packet loss. Follow these steps to control
TCN flooding:
Procedure
Command or Action
Purpose
Step 1
enable
Example:
Switch> enable
Enables
privileged EXEC mode. Enter your password if prompted.
Step 2
configure terminal
Example:
Switch# configure terminal
Enters the global
configuration mode.
Step 3
interface interface-id
Example:
Switch(config)# interface gigabitethernet 1/0/1
Specifies the
interface to be configured, and enters interface configuration mode.
Step 4
no ip igmp
snooping tcn flood
Example:
Switch(config-if)# no ip igmp snooping tcn flood
Disables the
flooding of multicast traffic during a spanning-tree TCN event.
By default,
multicast flooding is enabled on an interface.
Note
To re-enable
multicast flooding on an interface, use the ip igmp snooping tcn flood interface
configuration command.
Step 5
end
Example:
Switch(config)# end
Returns to
privileged EXEC mode.
Step 6
show ip igmp
snooping
Example:
Switch# show ip igmp snooping
Verifies the TCN
settings.
Step 7
copy running-config
startup-config
Example:
Switch# copy running-config startup-config
(Optional) Saves your entries
in the configuration file.
Configuring the IGMP Snooping Querier
Follow these steps to enable
the IGMP snooping querier feature in a VLAN:
Procedure
Command or Action
Purpose
Step 1
enable
Example:
Switch> enable
Enables
privileged EXEC mode. Enter your password if prompted.
Step 2
configure terminal
Example:
Switch# configure terminal
Enters the global
configuration mode.
Step 3
ip igmp snooping
querier
Example:
Switch(config)# ip igmp snooping querier
Enables the IGMP
snooping querier.
Step 4
ip igmp snooping
querier address ip_address
Example:
Switch(config)# ip igmp snooping querier address 172.16.24.1
(Optional)
Specifies an IP address for the IGMP snooping querier. If you do not specify an
IP address, the querier tries to use the global IP address configured for the
IGMP querier.
Note
The IGMP snooping
querier does not generate an IGMP general query if it cannot find an IP address
on the
switch.
Step 5
ip igmp snooping
querier query-interval interval-count
Example:
Switch(config)# ip igmp snooping querier query-interval 30
(Optional) Sets
the interval between IGMP queriers. The range is 1 to 18000 seconds.
Switch(config)# ip igmp snooping querier tcn query interval 20
(Optional) Sets
the time between Topology Change Notification (TCN) queries. The count range is
1 to 10. The interval range is 1 to 255 seconds.
Step 7
ip igmp snooping
querier timer expiry timeout
Example:
Switch(config)# ip igmp snooping querier timer expiry 180
(Optional) Sets
the length of time until the IGMP querier expires. The range is 60 to 300
seconds.
Step 8
ip igmp snooping
querier version version
Example:
Switch(config)# ip igmp snooping querier version 2
(Optional) Selects
the IGMP version number that the querier feature uses. Select 1 or 2.
Step 9
end
Example:
Switch(config)# end
Returns to
privileged EXEC mode.
Step 10
show ip igmp
snooping vlan vlan-id
Example:
Switch# show ip igmp snooping vlan 30
(Optional)
Verifies that the IGMP snooping querier is enabled on the VLAN interface. The
VLAN ID range is 1 to 1001 and 1006 to 4094.
Step 11
copy running-config
startup-config
Example:
Switch# copy running-config startup-config
(Optional) Saves your entries
in the configuration file.
Disabling IGMP Report Suppression
Follow these steps to disable
IGMP report suppression:
Procedure
Command or Action
Purpose
Step 1
enable
Example:
Switch> enable
Enables
privileged EXEC mode. Enter your password if prompted.
Step 2
configure terminal
Example:
Switch# configure terminal
Enters the global
configuration mode.
Step 3
no ip igmp
snooping report-suppression
Example:
Switch(config)# no ip igmp snooping report-suppression
Disables IGMP
report suppression. When report suppression is disabled, all IGMP reports are
forwarded to the multicast routers.
IGMP report suppression is enabled by default.
When IGMP report supression is enabled, the
switch
forwards only one IGMP report per multicast router query.
Note
To re-enable
IGMP report suppression, use the ip igmp snooping
report-suppression global configuration command.
Step 4
end
Example:
Switch(config)# end
Returns to
privileged EXEC mode.
Step 5
show ip igmp
snooping
Example:
Switch# show ip igmp snooping
Verifies that IGMP
report suppression is disabled.
Step 6
copy running-config
startup-config
Example:
Switch# copy running-config startup-config
(Optional) Saves your entries
in the configuration file.
Configuring MVR Global Parameters
You do not need to set the
optional MVR parameters if you choose to use the default settings. If you want
to change the default parameters (except for the MVR VLAN), you must first
enable MVR.
Note
For complete syntax and usage
information for the commands used in this section, see the command reference
for this release.
Procedure
Command or Action
Purpose
Step 1
enable
Example:
Switch> enable
Enables
privileged EXEC mode. Enter your password if prompted.
Step 2
configure terminal
Example:
Switch# configure terminal
Enters the global
configuration mode.
Step 3
mvr
Example:
Switch (config)# mvr
Enables MVR on the
switch.
Step 4
mvr group ip-address [count]
Example:
Switch(config)# mvr group
228.1.23.4
Configures an IP
multicast address on the
switch or use the
count parameter to configure a contiguous series
of MVR group addresses (the range for
count is 1 to 256; the default is 1). 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 would
correspond to one television channel.
Note
To return
the switch to its default settings, use the
no mvr [mode |
group ip-address |
querytime |
vlan ]
global configuration commands.
Step 5
mvr querytime value
Example:
Switch(config)# mvr querytime
10
(Optional) Defines
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 range is 1 to 100, and the default is 5 tenths or
one-half second.
Step 6
mvr vlan vlan-id
Example:
Switch(config)# mvr vlan 22
(Optional)
Specifies the VLAN in which multicast data is received; all source ports must
belong to this VLAN. The VLAN range is 1 to 1001 and 1006 to 4094. The default
is VLAN 1.
Step 7
mvr mode {dynamic |
compatible }
Example:
Switch(config)# mvr mode
dynamic
(Optional)
Specifies the MVR mode of operation:
dynamic —Allows dynamic MVR membership on source
ports.
compatible —Is compatible with Catalyst 3500 XL and
Catalyst 2900 XL
switches and does not support IGMP dynamic
joins on source ports.
The default is
compatible mode.
Note
To return
the switch to its default settings, use the
no mvr [mode |
group ip-address |
querytime |
vlan ]
global configuration commands.
Step 8
end
Example:
Switch(config)# end
Returns to
privileged EXEC mode.
Step 9
Use one of the following:
show
mvr
show mvr
members
Example:
Switch# show mvrORSwitch# show mvr members
Verifies the
configuration.
Step 10
copy running-config
startup-config
Example:
Switch# copy running-config startup-config
(Optional) Saves your entries
in the configuration file.
Configuring MVR Interfaces
Follow these steps to configure Layer 2 MVR interfaces:
Procedure
Command or Action
Purpose
Step 1
enable
Example:
Switch> enable
Enables
privileged EXEC mode. Enter your password if prompted.
Step 2
configure terminal
Example:
Switch# configure terminal
Enters the global
configuration mode.
Step 3
mvr
Example:
Switch (config)# mvr
Enables MVR on the
switch.
Step 4
interface interface-id
Example:
Switch(config)# interface
gigabitethernet1/0/2
Specifies the
Layer 2 port to configure, and enter interface configuration mode.
Step 5
mvr type {source |
receiver }
Example:
Switch(config-if)# mvr type receiver
Configures an MVR
port as one of these:
source —Configures 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 —Configures 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.
The default
configuration is as a non-MVR port. If you attempt to configure a non-MVR port
with MVR characteristics, the operation fails.
Note
To return
the interface to its default settings, use theno mvr
[type |
immediate |
vlan vlan-id |
group ] interface configuration commands.
Step 6
mvr vlan vlan-idgroup [ip-address]
Example:
Switch(config-if)# mvr vlan 22 group
228.1.23.4
(Optional)
Statically configures a port to receive multicast traffic sent to the multicast
VLAN and 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 to only 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 7
mvr
immediate
Example:
Switch(config-if)# mvr immediate
(Optional) Enables
the Immediate-Leave feature of MVR on the port.
Note
This command
applies to only receiver ports and should only be enabled on receiver ports to
which a single receiver device is connected.
Step 8
end
Example:
Switch(config)# end
Returns to
privileged EXEC mode.
Step 9
Use one of the following:
show mvr
show mvr
interface
show mvr
members
Example:
Switch# show mvr interface
Port Type Status Immediate Leave
---- ---- ------- ---------------
Gi1/0/2 RECEIVER ACTIVE/DOWN ENABLED
Verifies the
configuration.
Step 10
copy running-config
startup-config
Example:
Switch# copy running-config startup-config
(Optional) Saves your entries
in the configuration file.
Configuring IGMP Profiles
Follow these steps to create an IGMP profile:
This task is optional.
Procedure
Command or Action
Purpose
Step 1
enable
Example:
Switch> enable
Enables
privileged EXEC mode. Enter your password if prompted.
Step 2
configure terminal
Example:
Switch# configure terminal
Enters the global
configuration mode.
Step 3
ip igmp
profile profile number
Example:
Switch(config)# ip igmp profile 3
Assigns a number
to the profile you are configuring, and enters IGMP profile configuration mode.
The profile number range is 1 to 4294967295. When you are in IGMP profile
configuration mode, you can create the profile by using these commands:
deny —Specifies that matching addresses are denied;
this is the default.
exit —Exits
from igmp-profile configuration mode.
no —Negates a
command or returns to its defaults.
permit —Specifies that matching addresses are
permitted.
range —Specifies a range of IP addresses for the
profile. You can enter a single IP address or a range with a start and an end
address.
The default is for the
switch
to have no IGMP profiles configured.
Note
To delete a
profile, use the
no ip igmp profile profile
number global configuration command.
Step 4
permit |
deny
Example:
Switch(config-igmp-profile)# permit
(Optional) Sets
the action to permit or deny access to the IP multicast address. If no action
is configured, the default for the profile is to deny access.
Step 5
range ip multicast
address
Example:
Switch(config-igmp-profile)# range 229.9.9.0
Enters the IP
multicast address or range of IP multicast addresses to which access is being
controlled. If entering a range, enter the low IP multicast address, a space,
and the high IP multicast address.
You can use the
range command
multiple times to enter multiple addresses or ranges of addresses.
Note
To delete an
IP multicast address or range of IP multicast addresses, use the
no range ip multicast address
IGMP profile configuration command.
Step 6
end
Example:
Switch(config)# end
Returns to
privileged EXEC mode.
Step 7
show ip igmp
profile profile number
Example:
Switch# show ip igmp profile 3
Verifies the
profile configuration.
Step 8
show running-config
Example:
Switch# show running-config
Verifies your entries.
Step 9
copy running-config
startup-config
Example:
Switch# copy running-config startup-config
(Optional) Saves your entries
in the configuration file.
Applying IGMP Profiles
To control access as defined
in an IGMP profile, you have to apply the profile to the appropriate
interfaces. You can apply IGMP profiles only to Layer 2 access ports; you
cannot apply IGMP profiles to routed ports or SVIs. You cannot apply profiles
to ports that belong to an EtherChannel port group. You can apply a profile to
multiple interfaces, but each interface can have only one profile applied to
it.
Follow these steps to apply an IGMP profile to a switch port:
Procedure
Command or Action
Purpose
Step 1
enable
Example:
Switch> enable
Enables
privileged EXEC mode. Enter your password if prompted.
Step 2
configure terminal
Example:
Switch# configure terminal
Enters the global
configuration mode.
Step 3
interface interface-id
Example:
Switch(config)# interface gigabitethernet1/0/1
Specifies the
physical interface, and enters interface configuration mode. The interface must
be a Layer 2 port that does not belong to an EtherChannel port group.
Step 4
ip igmp
filter profile number
Example:
Switch(config-if)# ip igmp filter 321
Applies the
specified IGMP profile to the interface. The range is 1 to 4294967295.
Note
To remove a
profile from an interface, use theno ip
igmp filter
profile number interface configuration command.
Step 5
end
Example:
Switch(config-if)# end
Returns to
privileged EXEC mode.
Step 6
show running-config
Example:
Switch# show running-config
Verifies your entries.
Step 7
copy running-config
startup-config
Example:
Switch# copy running-config startup-config
(Optional) Saves your entries
in the configuration file.
Setting the Maximum Number of IGMP Groups
Follow these steps to set the
maximum number of IGMP groups that a Layer 2 interface can join:
Before you begin
This
restriction can be applied to Layer 2 ports only; you cannot set a maximum
number of IGMP groups on routed ports or SVIs. You also can use this command on
a logical EtherChannel interface but cannot use it on ports that belong to an
EtherChannel port group.
Procedure
Command or Action
Purpose
Step 1
enable
Example:
Switch> enable
Enables
privileged EXEC mode. Enter your password if prompted.
Step 2
configure terminal
Example:
Switch# configure terminal
Enters the global
configuration mode.
Step 3
interface interface-id
Example:
Switch(config)# interface gigabitethernet1/0/2
Specifies the
interface to be configured, and enters interface configuration mode. The
interface can be a Layer 2 port that does not belong to an EtherChannel group
or a EtherChannel interface.
Step 4
ip igmp
max-groups number
Example:
Switch(config-if)# ip igmp max-groups 20
Sets the maximum
number of IGMP groups that the interface can join. The range is 0 to
4294967294. The default is to have no maximum set.
Note
To remove
the maximum group limitation and return to the default of no maximum, use the
no ip igmp
max-groups interface configuration command.
Step 5
end
Example:
Switch(config)# end
Returns to
privileged EXEC mode.
Step 6
show
running-config interface interface-id
Example:
Switch# show running-config interface gigabitethernet1/0/1
Verifies your
entries.
Step 7
copy running-config
startup-config
Example:
Switch# copy running-config startup-config
(Optional) Saves your entries
in the configuration file.
Configuring the IGMP Throttling Action
After you set the maximum number of IGMP groups that a Layer 2 interface can
join, you can configure an interface to replace the existing group with the new
group for which the IGMP report was received.
Follow these steps to configure the throttling action when the maximum
number of entries is in the forwarding table:
Procedure
Command or Action
Purpose
Step 1
enable
Example:
Switch> enable
Enables
privileged EXEC mode. Enter your password if prompted.
Step 2
configure terminal
Example:
Switch# configure terminal
Enters the global
configuration mode.
Step 3
interface interface-id
Example:
Switch(config)# interface gigabitethernet 1/0/1
Specifies the
physical interface to be configured, and enters interface configuration mode.
The interface can be a Layer 2 port that does not belong to an EtherChannel
group or an EtherChannel interface. The interface cannot be a trunk port.
Step 4
ip igmp max-groups
action {deny |
replace }
Example:
Switch(config-if)# ip igmp max-groups action replace
When an interface
receives an IGMP report and the maximum number of entries is in the forwarding
table, specifies the action that the interface takes:
deny —Drops the report. If you configure this
throttling action, the entries that were previously in the forwarding table are
not removed but are aged out. After these entries are aged out and the maximum
number of entries is in the forwarding table, the
switch
drops the next IGMP report received on the interface.
replace —Replaces the existing group with the new
group for which the IGMP report was received. If you configure this throttling
action, the entries that were previously in the forwarding table are removed.
When the maximum number of entries is in the forwarding table, the
switch
replaces a randomly selected entry with the received IGMP report.
To prevent the
switch
from removing the forwarding-table entries, you can configure the IGMP
throttling action before an interface adds entries to the forwarding table.
Note
To return to
the default action of dropping the report, use the
no ip igmp max-groups
action interface configuration command.
Step 5
end
Example:
Switch(config)# end
Returns to
privileged EXEC mode.
Step 6
show
running-config interface interface-id
Example:
Switch# show running-config interface gigabitethernet1/0/1
Verifies your
entries.
Step 7
copy running-config
startup-config
Example:
Switch# copy running-config startup-config
(Optional) Saves your entries
in the configuration file.
Monitoring IGMP Snooping and MVR
Monitoring IGMP
Snooping Information
You can display IGMP
snooping information for dynamically learned and statically configured router
ports and VLAN interfaces. You can also display MAC address multicast entries
for a VLAN configured for IGMP snooping.
Table 6. Commands for
Displaying IGMP Snooping Information
Command
Purpose
show ip igmp snooping
[vlan vlan-id ]
Displays the snooping
configuration information for all VLANs on the
switch or for a specified VLAN.
(Optional) Enter
vlan vlan-id to
display information for a single VLAN. The VLAN ID range is 1 to 1001 and 1006
to 4094.
show ip igmp snooping groups
[count |dynamic [count ] |
user [count ]]
Displays multicast table
information for the
switch or about a specific parameter:
count —Displays the total number of entries for the
specified command options instead of the actual entries.
dynamic —Displays entries learned through IGMP
snooping.
user —Displays only the user-configured multicast
entries.
show ip igmp
snooping groups vlan vlan-id
[ip_address
|
count |
dynamic [count ] |
user [count ]]
Displays multicast table
information for a multicast VLAN or about a specific parameter for the VLAN:
vlan-id—The VLAN ID range is 1 to 1001 and 1006 to
4094.
count —Displays the total number of entries for the
specified command options instead of the actual entries.
dynamic —Displays entries learned through IGMP
snooping.
ip_address—Displays characteristics of the
multicast group with the specified group IP address.
user —Displays only the user-configured multicast
entries.
show ip igmp snooping mrouter
[vlan vlan-id]
Displays information on
dynamically learned and manually configured multicast router interfaces.
Note
When you enable IGMP snooping, the
switch automatically learns the interface to
which a multicast router is connected. These are dynamically learned
interfaces.
(Optional) Enter the
vlan vlan-id to
display information for a particular VLAN.
show ip igmp snooping
querier
[vlan vlan-id]
Display
information about the IP address and receiving port for the most-recently
received IGMP query messages in the VLAN.
(Optional)
Enter vlan vlan-id to display information for a single VLAN.
show ip igmp snooping
querier
[vlan vlan-id]
detail
Displays information about
the IP address and receiving port of the most-recently received IGMP query
message in the VLAN and the configuration and operational state of the IGMP
snooping querier in the VLAN.
Monitoring MVR
You can monitor MVR for the
switch or for a specified interface by displaying the following MVR
information.
Table 7. Commands for Displaying MVR
Information
Command
Purpose
show mvr
Displays MVR status and
values for the switch—whether MVR is enabled or disabled, the multicast VLAN,
the maximum (256) and current (0 through 256) number of multicast groups, 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 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. The VLAN ID range is 1 to 1001 and 1006 to
4094.
show mvr members [ip-address]
Displays all receiver and
source ports that are members of any IP multicast group or the specified IP
multicast group IP address.
Monitoring IGMP Filtering and Throttling Configuration
You can display IGMP profile
characteristics, and you can display the IGMP profile and maximum group
configuration for all interfaces on the
switch or for a specified interface. You can
also display the IGMP throttling configuration for all interfaces on the
switch or for a specified interface.
Table 8. Commands for Displaying IGMP
Filtering and Throttling Configuration
Command
Purpose
show ip igmp profile
[profile
number]
Displays the
specified IGMP profile or all the IGMP profiles defined on the
switch.
show running-config
[interface
interface-id]
Displays the configuration of
the specified interface or the configuration of all interfaces on the
switch, including (if configured) the maximum
number of IGMP groups to which an interface can belong and the IGMP profile
applied to the interface.
Configuration Examples for IGMP Snooping and MVR
Example: Configuring
IGMP Snooping Using CGMP Packets
This example shows how to
configure IGMP snooping to use CGMP packets as the learning method:
Switch# configure terminalSwitch(config)# ip igmp snooping vlan 1 mrouter learn cgmpSwitch(config)# end
Example: Enabling a
Static Connection to a Multicast Router
This example shows
how to enable a static connection to a multicast router:
Example: Configuring
a Host Statically to Join a Group
This example shows
how to statically configure a host on a port:
Switch# configure terminalSwitch# ip igmp snooping vlan 105 static 224.2.4.12 interface gigabitethernet1/0/1Switch# end
Example: Enabling
IGMP Immediate Leave
This example shows
how to enable IGMP Immediate Leave on VLAN 130:
Switch# configure terminalSwitch(config)# ip igmp snooping vlan 130 immediate-leaveSwitch(config)# end
Example: Setting the
IGMP Snooping Querier Source Address
This example shows
how to set the IGMP snooping querier source address to 10.0.0.64:
Switch# configure terminalSwitch(config)# ip igmp snooping querier 10.0.0.64Switch(config)# end
Example: Setting the
IGMP Snooping Querier Maximum Response Time
This example shows
how to set the IGMP snooping querier maximum response time to 25 seconds:
Switch# configure terminalSwitch(config)# ip igmp snooping querier query-interval 25Switch(config)# end
Example: Setting the
IGMP Snooping Querier Timeout
This example shows
how to set the IGMP snooping querier timeout to 60 seconds:
Switch# configure terminalSwitch(config)# ip igmp snooping querier timeout expiry 60Switch(config)# end
Example: Setting the
IGMP Snooping Querier Feature
This example shows
how to set the IGMP snooping querier feature to Version 2:
Switch# configure terminalSwitch(config)# no ip igmp snooping querier version 2Switch(config)# end
Example: Configuring
IGMP Profiles
This example shows how to
create IGMP profile 4 allowing access to the single IP multicast address and
how to verify the configuration. If the action was to deny (the default), it
would not appear in the
show ip igmp profile
output display.
Switch(config)# ip igmp profile 4Switch(config-igmp-profile)# permitSwitch(config-igmp-profile)# range 229.9.9.0Switch(config-igmp-profile)# endSwitch# show ip igmp profile 4
IGMP Profile 4
permit
range 229.9.9.0 229.9.9.0
Example: Applying
IGMP Profile
This example shows how to
apply IGMP profile 4 to a port:
Switch(config)# interface gigabitethernet1/0/2Switch(config-if)# ip igmp filter 4Switch(config-if)# end
Example: Setting the
Maximum Number of IGMP Groups
This example shows how to
limit to 25 the number of IGMP groups that a port can join:
Switch(config)# interface gigabitethernet1/0/2Switch(config-if)# ip igmp max-groups 25Switch(config-if)# end
Example: Configuring
MVR Global Parameters
This example shows
how to enable MVR, configure the group address, set the query time to 1 second
(10 tenths), specify the MVR multicast VLAN as VLAN 22, and set the MVR mode as
dynamic:
Switch(config)# mvrSwitch(config)# mvr group 228.1.23.4Switch(config)# mvr querytime 10Switch(config)# mvr vlan 22Switch(config)# mvr mode dynamicSwitch(config)# end
Example: Configuring
MVR Interfaces
This example shows
how to configure a port as a receiver port, statically configure the port to
receive multicast traffic sent to the multicast group address, configure
Immediate Leave on the port, and verify the results:
Switch(config)# mvrSwitch(config)# interface gigabitethernet1/0/2Switch(config-if)# mvr type receiverSwitch(config-if)# mvr vlan 22 group 228.1.23.4Switch(config-if)# mvr immediateSwitch(config)# endSwitch# show mvr interface
Port Type Status Immediate Leave
---- ---- ------- ---------------
Gi1/0/2 RECEIVER ACTIVE/DOWN ENABLED
Additional
References
Related
Documents
Related
Topic
Document
Title
For
complete syntax and usage information for the commands used in this chapter.
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