Router-Port Group Management Protocol
This feature module describes the Router-Port Group Management Protocol (RGMP) feature and
includes the following sections:
Note
•
Feature Overview, page 1
•
Supported Platforms, page 7
•
Prerequisites, page 8
•
Configuration Tasks, page 8
•
Monitoring and Maintaining RGMP, page 9
•
Configuration Examples, page 10
•
Command Reference, page 13
•
Debug Commands, page 15
•
Glossary, page 17
This feature was introduced in Cisco IOS Release 12.0(10)S and later integrated into
Cisco IOS Release 12.1(1)E and Cisco IOS Release 12.1(5)T.
Feature Overview
The Router-Port Group Management Protocol (RGMP) feature introduces a Cisco protocol that restricts
IP multicast traffic in switched networks. RGMP is a Layer 2 protocol that enables a router to
communicate to a switch (or a networking device that is functioning as a Layer 2 switch) the multicast
group for which the router would like to receive or forward traffic. RGMP restricts multicast traffic at
the ports of RGMP-enabled switches that lead to interfaces of RGMP-enabled routers. RGMP is
designed for switched Ethernet backbone networks running Protocol Independent Multicast (PIM)
sparse mode.
Note
RGMP-enabled switches and router interfaces in a switched network support directly
connected, multicast-enabled hosts that receive multicast traffic. RGMP-enabled switches
and router interfaces in a switched network do not support directly connected,
multicast-enabled hosts that source multicast traffic. A multicast-enabled host can be a
PC, a workstation, or a multicast application running in a router.
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Router-Port Group Management Protocol
Feature Overview
Cisco Group Management Protocol (CGMP) and Internet Group Management Protocol (IGMP)
snooping are existing Layer 2 protocols that restrict multicast traffic from switches to hosts. However,
unlike RGMP, CGMP and IGMP snooping do not restrict multicast traffic from switches to routers.
Note
RGMP and IGMP snooping interoperate in the same switched network; RGMP and CGMP
do not interoperate in the same switched network. If RGMP is enabled on a switch or
router interface, CGMP is automatically disabled on that switch or router interface; if
CGMP is enabled on a switch or router interface, RGMP is automatically disabled on that
switch or router interface.
Switches in a network running CGMP or IGMP snooping forward multicast traffic out all ports that lead
to router interfaces in the network because the routers cannot communicate to the switches, using
CGMP or IGMP, the multicast traffic that the routers want to forward to other networks. Routers use
IGMP only to communicate to switches the multicast traffic the routers want to receive for multicast
applications running in the routers.
Figure 1 shows a switched Ethernet backbone network running PIM in sparse mode, RGMP, and IGMP
snooping.
RGMP in a Switched Network
Router B
PIM SM
RGMP
Router A
PIM SM
RGMP
A
B
B
A
Source for
group A
Switched network
B
Source for
group B
B
A
A
A
Receiver 1
for group A
A
Receiver 2
for group A
A
B
Switch A
RGMP
IGMP
snooping
B
Switch B
RGMP
IGMP
snooping
B
Receiver 1
for group B
A
Router D
PIM SM
RGMP
Router C
PIM SM
RGMP
Traffic restricted by RGMP
B
39165
Figure 1
Receiver 2
for group B
In Figure 1, the sources for the two different multicast groups (the source for group A and the source
for group B) send traffic into the same switched network. Without RGMP, traffic from source A is
unnecessarily flooded from switch A to switch B, then to router B and router D. Also, traffic from
source B is unnecessarily flooded from switch B to switch A, then to router A and router C. With
RGMP enabled on all routers and switches in this network, traffic from source A would not flood
router B and router D. Also, traffic from source B would not flood router A and router C. Traffic from
both sources would still flood the link between switch A and switch B. Flooding over this link would
still occur because RGMP does not restrict traffic on links toward other RGMP-enabled switches with
routers behind them.
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Feature Overview
Figure 2 shows the RGMP messages sent between an RGMP-enabled router and an RGMP-enabled
switch.
Figure 2
RGMP Messages
PIM SM
RGMP
RGMP
IGMP Snooping
PIM Hello
RGMP Hello
X
RGMP Join <G>
All multicast packets
Multicast packets for group <G>
RGMP Leave <G>
All multicast packets
Multicast packets for group <G>
42759
RGMP Bye
X
The router sends simultaneous PIM Hello (or a PIM Query message if PIM version 1 is configured) and
RGMP Hello messages to the switch. The PIM Hello message is used to locate neighboring PIM routers.
The RGMP Hello message instructs the switch to restrict all multicast traffic on the interface from
which the switch received the RGMP Hello message.
Note
RGMP messages are sent to the multicast address 224.0.0.25, which is the local-link
multicast address reserved by the Internet Assigned Numbers Authority (IANA) for
sending IP multicast traffic from routers to switches.
If RGMP is not enabled on both the router and the switch, the switch automatically
forwards all multicast traffic out the interface from which the switch received the PIM
Hello message.
The router sends the switch an RGMP Join <G> message (where G is the multicast group address) when
the router wants to receive traffic for a specific multicast group. The RGMP Join message instructs the
switch to forward multicast traffic for group <G> out the interface from which the switch received the
RGMP Hello message.
Note
The router sends the switch an RGMP Join <G> message for a multicast group even if the
router is only forwarding traffic for the multicast group into a switched network. By
joining a specific multicast group, the router can determine if another router is also
forwarding traffic for the multicast group into the same switched network. If two routers
are forwarding traffic for a specific multicast group into the same switched network, the
two routers use the PIM assert mechanism to determine which router should continue
forwarding the multicast traffic into the network.
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Feature Overview
The router sends the switch an RGMP Leave <G> message when the router wants to stop receiving
traffic for a specific multicast group. The RGMP Leave message instructs the switch to stop forwarding
the multicast traffic on the port from which the switch received the PIM and RGMP Hello messages.
Note
An RGMP-enabled router cannot send an RGMP Leave <G> message until the router does
not receive or forward traffic from any source for a specific multicast group (if multiple
sources exist for a specific multicast group).
The router sends the switch an RGMP Bye message when RGMP is disabled on the router. The RGMP
Bye message instructs the switch to forward the router all IP multicast traffic on the port from which
the switch received the PIM and RGMP Hello messages, as long as the switch continues to receive PIM
Hello messages on the port.
Benefits
Increases Available Bandwidth
By restricting unwanted multicast traffic in a switched network, RGMP increases the available
bandwidth for all other multicast traffic in the network. Without RGMP, the sum of all multicast traffic
sent into a switched network must be smaller than the slowest link on the slowest router can sustain.
With RGMP, this restriction is limited. Multicast traffic will flood only on links between switches in the
network, whereas routers will receive only the multicast traffic that they need.
Increases Scalability for Multicast Traffic
In a switched Ethernet network where RGMP is not enabled and n routers (n being any number of
routers) are connected to a single switch through individual 100-Mbps full-duplex connections, the
theoretical maximum aggregate bandwidth for unicast traffic sent into the network is n * 100 Mbps and
the theoretical maximum aggregate bandwidth for multicast traffic sent into the network is only
100 Mbps. When RGMP is enabled in this same network, the theoretical maximum aggregate
bandwidth for multicast traffic sent into the network changes to n * 100 Mbps.
Increases Available Resources
By eliminating unwanted multicast traffic in a switched network, routers need not devote processing
resources to examining unwanted multicast packets.
Limited Impact on Router and Switch Efficiency
RGMP has limited impact on router and switch processing resources and does not require additional
system memory. RGMP also does not introduce new timers or other control mechanisms in routers that
might introduce new error conditions.
Restrictions
General Restrictions
•
For Catalyst switches running CatOS, RGMP is configured for the entire switch. For Cisco routers,
RGMP is configured on specific interfaces. RGMP remains passive on Catalyst switches (and in the
entire switched network) until RGMP is configured on a router interface that is connected to the
switched network.
•
RGMP is only supported on Ethernet, Fast Ethernet, and Gigabit Ethernet interfaces.
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Feature Overview
•
RGMP is supported on interfaces on which the ip pim sparse-mode or ip pim sparse-dense-mode
command has been used. RGMP is not supported on interfaces on which the ip pim dense-mode
command has been used.
•
RGMP is supported in groups that are in PIM sparse mode and PIM source specific mode. It is also
supported in groups that are in bidirectional mode except for interfaces that function as the
designated forwarder (DF). RGMP is not supported in groups that are in PIM dense mode.
Note
RGMP interoperates with the Auto-Rendezvous Point (Auto-RP) protocol in PIM
dense mode. Specifically, multicast traffic that is sent to reserved multicast
addresses 224.0.1.39 and 224.0.1.40 from interfaces that have been configured
with the ip pim sparse-dense-mode command is never restricted by RGMP
because these two addresses utilize the Auto-RP protocol in PIM dense mode. No
other multicast addresses are supported in PIM dense mode.
•
Do not configure RGMP on a router interface that is functioning as the DF for a bidirectional PIM
group. Doing so will keep the DF from forwarding multicast packets up the bidirectional shared
tree to the rendezvous point (RP).
•
RGMP and CGMP do not interoperate. If RGMP is enabled on a switch or router, CGMP is
automatically disabled; if CGMP is enabled on a switch or router, RGMP is automatically disabled.
•
Routers that are not enabled for RGMP are supported in an RGMP network; however, all multicast
traffic in the network is forwarded to these routers.
Topology Restrictions
•
RGMP-enabled switches and router interfaces in a switched network support directly connected,
multicast-enabled hosts that receive multicast traffic. RGMP-enabled switches and router interfaces
in a switched network do not support directly connected, multicast-enabled hosts that source
multicast traffic. A multicast-enabled host can be a PC, a workstation, or a multicast application
running in a router. Cisco IOS software utilities that source multicast traffic (for example, mtrace)
are not supported in RGMP networks. However, functionality associated with the ip sdr listen
command is supported because the functionality only receives multicast traffic.
•
Do not configure Multicast Routing Monitor (MRM) on a router interface that is already configured
for RGMP.
Note
RGMP is intended and most beneficial for switched backbone networks, for
switched exchange point networks between different domains, or for general
switched networks in which traffic flows between routers.
•
RGMP is a point-to point protocol. When an RGMP-enabled switch receives an RGMP message,
the switch assumes that the message was sent from a connected RGMP-enabled router. RGMP does
not work properly when Ethernet hubs or RGMP-disabled switches are used to interconnect the
ports and interfaces of RGMP-enabled routers and switches. We do not recommend using hubs or
RGMP-disabled switches in an RGMP network. If you must include RGMP-disabled routers in an
RGMP network, configure the RGMP-disabled routers on separate, individual ports of
RGMP-enabled switches that are not shared by other routers.
•
Each RGMP segment must connect only two ports of two separate RGMP-enabled devices
(a router or switch). An RGMP segment is the Ethernet between the two RGMP-enabled devices.
•
A host PC or workstation can be added to any RGMP segment. Connect only a host PC or
workstation to individual switch ports to achieve the best traffic suppression per host.
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Feature Overview
•
Do not connect an RGMP-enabled router and an RGMP-disabled router to an RGMP-disabled
switch. Use RGMP-disabled switches in your RGMP network as leaf switches, where one port of
the RGMP-disabled switch is connected to an RGMP-enabled switch and the remaining ports of
the RGMP-disabled switch are connected to hosts.
•
RGMP-enabled router ports should be directly connected to switched ports on RGMP-enabled
switches. An RGMP-enabled router port may share an RGMP segment with a host port, but not with
another router port (RGMP enabled or disabled).
•
Because all multicast traffic is forwarded to RGMP-disabled routers in an RGMP network, we
recommend placing RGMP-disabled routers in one or more RGMP segments off the same
RGMP-enabled switch. Doing so isolates the multicast traffic to the RGMP-disabled routers. Do
not put RGMP-disabled routers in segments at opposite edges of an RGMP network.
Note
RGMP-enabled and RGMP-disabled routers must reside on separate RGMP
segments. RGMP-enabled and RGMP-disabled routers cannot share the same
RGMP segment.
Layer 2 Restrictions
The following restrictions are specific to configuring RGMP on switches:
•
RGMP does not restrict multicast traffic between MAC-layer ambiguous multicast addresses.
RGMP restricts traffic on multicast group addresses; however, Catalyst switches running RGMP
only restrict multicast traffic based on the Ethernet MAC addresses that map to the IP address of
the multicast group. If a router needs to receive traffic for a specific multicast group, RGMP will
not effectively suppress traffic for all multicast groups that are MAC-layer ambiguous with the
specific multicast group. Multicast groups are MAC-layer ambiguous if they have the same trailing
23 bits in their multicast addresses. For example, multicast group address 224.0.47.11 is
MAC-layer ambiguous with multicast group address 224.128.47.11 through 239.128.47.11.
•
RGMP does not restrict traffic for local-link multicast addresses 224.0.0.x. The multicast addresses
in this network are always forwarded and are not restricted by either RGMP or IGMP snooping.
Unless the specific switches in your network support restricting traffic for local-link multicast
addresses in 224.0.0.x, traffic is also not suppressed on multicast group addresses that are
MAC-layer ambiguous to local-link multicast addresses in 224.0.0.x.
•
Traffic restriction in switches is limited by the amount of available forwarding state memory
(typically some form of content-addressable memory that holds forwarding state information for
thousands of multicast groups). If the available forwarding state memory is exceeded, traffic for
additional multicast groups is forwarded within the network.
•
RGMP restricts traffic based on the destination IP address of a multicast group; RGMP does not
restrict traffic based on the IP address of a multicast source or a router forwarding traffic into a
switched network. When specified by an RGMP Join message, RGMP restricts all traffic for a
multicast group regardless of the traffic source or forwarding router.
Related Features and Technologies
In Cisco IOS Release 12.1(5)T or later releases, RGMP interoperates with the Source Specific Multicast
(SSM) feature. For more information on the Source Specific Multicast feature, refer to the Source
Specific Multicast with IGMPv3, IGMPv3lite, and URD document in the “New Features in Release
12.1(5)T” area of Cisco Connection Online.
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Supported Platforms
RGMP is related to CGMP, IGMP snooping, PIM sparse mode, and IP multicast over ATM
Point-to-Multipoint virtual circuits (ATM PTMP-VCs).
Refer to the “IP Multicast” part of the Release 12.1 Cisco IOS IP and IP Routing Configuration Guide
and the Cisco IOS IP and IP Routing Command Reference, and the Catalyst switch software
configuration guides for configuration and command reference information on CGMP and PIM sparse
mode.
Refer to the “Constrained Multicast Flooding (CMF)” section of the “Configuring Transparent
Bridging” chapter of the Release 12.1 Cisco IOS Bridging and IBM Networking Configuration Guide
and the “Transparent Bridging Commands” chapter of the Cisco IOS Bridging and IBM Networking
Command Reference, Vol 1 for configuration and command reference information on IGMP snooping
on Cisco routers functioning as Layer 2 switches or transparent bridges. Additionally, refer to the
Catalyst switch software configuration guides for configuration and command reference information on
IGMP snooping.
Note
All Catalyst switches, except the Catalyst 6000 series switches, support CGMP. (The
Supervisor Engine for the Catalyst 6000 series switches does not support CGMP at
Layer 2. The Multilayer Switch Feature Card [MSFC] for the Catalyst 6000 series
switches supports CGMP at Layer 3.) IGMP snooping is currently supported on the
Catalyst 4000 series, Catalyst 5000 series, and the Catalyst 6000 series switches.
The benefits of RGMP for IP multicast over a switched Ethernet network are similar to the benefits of
ATM PTMP-VC for IP multicast over an ATM network. The differences in benefits are that the ATM
PTMP-VC feature only supports PIM routers in the network receiver (RGMP supports hosts in addition
to PIM routers) and that ATM PTMP-VC restricts traffic based on the multicast group, the multicast
source, and the forwarding router (RGMP restricts traffic based on the IP multicast group). ATM
PTMP-VC provides better traffic restriction than RGMP; however, RGMP in a switched Ethernet
network is a less complex and less expensive solution. Refer to the “IP Multicast” part of the Release
12.1 Cisco IOS IP and IP Routing Configuration Guide and the Cisco IOS IP and IP Routing Command
Reference for configuration and command reference information on the ATM PTMP-VC feature.
Supported Platforms
RGMP is supported on the following platforms:
•
Catalyst 5000 series
•
Catalyst 6000 series
•
Cisco 800 series
•
Cisco 1400 series
•
Cisco 1600 series
•
Cisco 1700 series
•
Cisco 2500 series
•
Cisco 2600 series
•
Cisco 3600 series
•
Cisco 4000 series (Cisco 4000, 4000-M, 4500, 4500-M, 4700, 4700-M)
•
Cisco 6400 universal access concentrator
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Supported Standards, MIBs, and RFCs
•
Cisco 7000 series
•
Cisco 7200 series
•
Cisco 7500 series
•
Cisco AS5800 access server
•
Cisco AS5400 series
•
Cisco AS5300 series
•
Cisco AS5200 series
•
Cisco MC3810 series
•
Cisco MGX8850 WAN edge switch
•
Cisco uBR7200 series
Supported Standards, MIBs, and RFCs
Standards
No new or modified standards are supported by this feature.
MIBs
No new or modified MIBs are supported by this feature.
To obtain lists of MIBs supported by platform and Cisco IOS releases, and to download MIB modules,
go to the Cisco MIB web site on Cisco Connection Online (CCO) at
http://www.cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml.
RFCs
No new or modified RFCs are supported by this feature.
Prerequisites
•
You must have IP routing, IP multicast, and PIM in sparse mode or sparse-dense mode enabled on
your router before enabling RGMP.
•
You must have IP multicast and IGMP snooping enabled on your switch before enabling RGMP.
Configuration Tasks
To configure RGMP, first ensure that your network meets the prerequisites listed in the previous section,
then use the following commands on all routers in your network beginning in global configuration
mode.
Note
Refer to the Catalyst switch software documentation for RGMP switch configuration tasks
and command information.
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Monitoring and Maintaining RGMP
Command
Purpose
Step 1
Router(config)# interface type number
Router(config-if)#
Specifies the specific router interface on which you
want to configure RGMP and enters interface
configuration mode.
Step 2
Router(config-if)# ip rgmp
Enables RGMP on a specified interface.
Verifying RGMP Configuration
To verify that RGMP is enabled on the correct interfaces, use the show ip igmp interface EXEC
command:
Router> show ip igmp interface
Ethernet1/0 is up, line protocol is up
Internet address is 10.0.0.0/24
IGMP is enabled on interface
Current IGMP version is 2
RGMP is enabled
IGMP query interval is 60 seconds
IGMP querier timeout is 120 seconds
IGMP max query response time is 10 seconds
Last member query response interval is 1000 ms
Inbound IGMP access group is not set
IGMP activity: 1 joins, 0 leaves
Multicast routing is enabled on interface
Multicast TTL threshold is 0
Multicast designated router (DR) is 10.0.0.0 (this system)
IGMP querying router is 10.0.0.0 (this system)
Multicast groups joined (number of users):
224.0.1.40(1)
Note
If RGMP is not enabled on an interface, no RGMP information is displayed in the show
ip igmp interface command output for that interface.
Monitoring and Maintaining RGMP
To enable RGMP debugging, use the following command in privileged EXEC mode:
Command
Purpose
Router# debug ip rgmp [group-name | group-address]
Logs debug messages sent by an RGMP-enabled
router.
Using the command without arguments logs
RGMP Join <G> and RGMP Leave <G> messages
for all multicast groups configured on the router.
Using the command with arguments logs RGMP
Join <G> and RGMP Leave <G> messages for the
specified group.
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Configuration Examples
Figure 3 shows the debug messages that are logged by an RGMP-enabled router as the router sends
RGMP Join <G> and RGMP Leave <G> messages to an RGMP-enabled switch.
Figure 3
RGMP Debug Messages
PIM SM
RGMP
RGMP
IGMP snooping
PIM Hello
RGMP Hello
RGMP: Sending a Hello packet on Ethernet1/0
X
RGMP Join 224.1.2.3
All multicast packets
RGMP: Sending a Join packet on Ethernet1/0 for group 224.1.2.3
Multicast packets for group 224.1.2.3
RGMP Leave 224.1.2.3
RGMP: Sending a Leave packet on Ethernet1/0 for group 224.1.2.3
Multicast packets for group 224.1.2.3
RGMP Bye
X
All multicast packets
42760
RGMP: Sending a Bye packet on Ethernet1/0
Configuration Examples
The following example shows the individual configurations for the routers and switches shown in
Figure 4.
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Configuration Examples
Figure 4
RGMP Configuration Example
1/0
Router B
PIM SM
RGMP
Router A
PIM SM
RGMP
1/1
1/0
1/1
Source for
group B
Source for
group A
Receiver 1
for group A
1/1
Switch A
RGMP
IGMP
snooping
Switch B
RGMP
IGMP
snooping
Receiver 1
for group B
1/1
1/0
Router C
PIM SM
RGMP
Router D
PIM SM
RGMP
42758
Receiver 2
for group A
1/0
Receiver 2
for group B
Router A
ip routing
ip multicast-routing
interface ethernet 1/0
ip address 10.0.0.1 255.0.0.0
ip pim sparse-dense-mode
no shutdown
interface ethernet 1/1
ip address 10.1.0.1 255.0.0.0
ip pim sparse-dense-mode
ip rgmp
no shutdown
Router B
ip routing
ip multicast-routing
interface ethernet 1/0
ip address 10.2.0.1 255.0.0.0
ip pim sparse-dense-mode
no shutdown
interface ethernet 1/1
ip address 10.3.0.1 255.0.0.0
ip pim sparse-dense-mode
ip rgmp
no shutdown
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Configuration Examples
Router C
ip routing
ip multicast-routing
interface ethernet 1/0
ip address 10.4.0.1 255.0.0.0
ip pim sparse-dense-mode
no shutdown
interface ethernet 1/1
ip address 10.5.0.1 255.0.0.0
ip pim sparse-dense-mode
ip rgmp
no shutdown
Router D
ip routing
ip multicast-routing
interface ethernet 1/0
ip address 10.6.0.1 255.0.0.0
ip pim sparse-dense-mode
no shutdown
interface ethernet 1/1
ip address 10.7.0.1 255.0.0.0
ip pim sparse-dense-mode
ip rgmp
no shutdown
Switch A
Switch> (enable) set igmp enable
Switch> (enable) set rgmp enable
Switch B
Switch> (enable) set igmp enable
Switch> (enable) set rgmp enable
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Command Reference
Command Reference
This section documents the new ip rgmp command. All other commands used with this feature are
documented in the Cisco IOS Release 12.1 command reference publications.
Note
Refer to the Catalyst switch software documentation for RGMP switch configuration tasks
and command information.
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ip rgmp
ip rgmp
To enable the Router-Port Group Management Protocol (RGMP) on IEEE 802.3 Ethernet interfaces, use
the ip rgmp interface configuration command. To disable RGMP on the interfaces, use the no form of
this command.
ip rgmp
no ip rgmp
Syntax Description
This command has no arguments or keywords.
Defaults
RGMP is not enabled.
Command Modes
Interface configuration
Command History
Release
Modification
12.0(10)S
This command was introduced.
12.1(1)E
This command was integrated into Cisco IOS Release 12.1(1)E.
12.1(5)T
This command was integrated into Cisco IOS Release 12.1(5)T.
Usage Guidelines
RGMP is supported only on IEEE 802.3 Ethernet interfaces.
You must have IP routing, IP multicast, and PIM in sparse mode enabled on your router before enabling
RGMP.
You must have IP multicast and IGMP snooping enabled on your switch before enabling RGMP.
See the “Restrictions” section earlier in this document for additional RGMP usage guidelines.
Examples
The following example enables RGMP on Ethernet interface 1/0:
Router(config)# interface ethernet 1/0
Router(config-if)# ip rgmp
Related Commands
Command
Description
debug ip rgmp
Logs debug messages sent by an RGMP-enabled router.
show ip igmp interface Displays multicast-related information about an interface.
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Debug Commands
Debug Commands
This section documents the new debug ip rgmp command related to the Router-Port Group
Management Protocol feature. All other commands used with this feature are documented in the Cisco IOS
Release 12.1 command reference publications.
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debug ip rgmp
debug ip rgmp
To log debug messages sent by an RGMP-enabled router, use the debug ip rgmp privileged EXEC
command. To disable RGMP debugging, use the no form of this command.
debug ip rgmp [group-name | group-address]
no debug ip rgmp
Syntax Description
group-name
(Optional) The name of a specific IP multicast group.
group-address
(Optional) The IP address of a specific IP multicast group.
Defaults
Debugging for RGMP is not enabled. If the debug ip rgmp command is used without arguments,
debugging is enabled for all RGMP message types.
Command Modes
Privileged EXEC
Command History
Release
Modification
12.0(10)S
This command was introduced.
12.1(1)E
This command was integrated into Cisco IOS Release 12.1(1)E.
12.1(5)T
This command was integrated into Cisco IOS Release 12.1(5)T.
Examples
The following example shows output for the debug ip rgmp command:
Router# debug ip rgmp
RGMP: Sending a Hello packet on Ethernet1/0
RGMP: Sending a Join packet on Ethernet1/0 for group 224.1.2.3
RGMP: Sending a Leave packet on Ethernet1/0 for group 224.1.2.3
RGMP: Sending a Bye packet on Ethernet1/0
Related Commands
Command
Description
ip rgmp
Enables the RGMP on IEEE 802.3 Ethernet interfaces.
show ip igmp interface Displays multicast-related information about an interface.
Cisco IOS Release 12.0(10)S, 12.1(1)E, and 12.1(5)T
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Router-Port Group Management Protocol
Glossary
Glossary
Auto-RP—IP multicast protocol developed by Cisco that automates the distribution of
group-to-rendezvous point (RP) mappings in a PIM network.
Cisco Group Management Protocol—See CGMP.
CGMP—Cisco Group Management Protocol. IP multicast protocol developed by Cisco. CGMP is used
by Cisco routers to restrict IP multicast traffic on Catalyst switch ports that are directly or indirectly
(through another switch) connected to hosts.
Internet Group Management Protocol (IGMP) snooping—See IGMP snooping.
IGMP snooping—A mechanism used by switches—IGMP snooping is transparent to hosts and
routers—to restrict IP multicast traffic on switch ports that are directly or indirectly (through another
switch) connected to hosts. Switches snoop, or examine, all multicast traffic from hosts for IGMP
membership report messages. When a switch discovers a membership report message sent by a host for
a multicast group, the switch sends multicast traffic for that group out the port that leads to the host (the
port on which the switch received the membership report message).
Router-Port Group Management Protocol—See RGMP.
RGMP—IP multicast protocol developed by Cisco that restricts IP multicast traffic to router ports.
RGMP is designed for switched networks where routers are interconnected by switches. RGMP reduces
multicast congestion in these networks by restricting unwanted IP multicast traffic on the ports of
RGMP-enabled switches that are directly or indirectly (through another RGMP-enabled switch)
connected to RGMP-enabled routers.
Cisco IOS Release 12.0(10)S, 12.1(1)E, and 12.1(5)T
17
Router-Port Group Management Protocol
Glossary
Cisco IOS Release 12.0(10)S, 12.1(1)E, and 12.1(5)T
18