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Monitoring and Maintaining IP Multicast

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Table Of Contents

Monitoring and Maintaining IP Multicast

Contents

Prerequisites for Monitoring and Maintaining IP Multicast

Information About Monitoring and Maintaining IP Multicast

IP Multicast Delivery Using IP Multicast Heartbeat

IP Multicast Heartbeat

SNMP Notifications

Session Announcement Protocol (SAP)

How to Monitor and Maintain IP Multicast

Displaying Multicast Peers, Packet Rates, and Loss Information, and Tracing a Path

Displaying IP Multicast System and Network Statistics

Clearing IP Multicast Routing Table or Caches

Monitoring IP Multicast Delivery Using IP Multicast Heartbeat

Advertising Multicast Multimedia Sessions Using SAP Listener

Storing IP Multicast Headers

Disabling Fast Switching of IP Multicast

Configuration Examples for Monitoring and Maintaining IP Multicast

Example: Displaying Multicast Peers, Packet Rates, and Loss Information, and Tracing a Path

Example: Displaying IP Multicast System and Network Statistics

Example: Monitoring IP Multicast Delivery Using IP Multicast Heartbeat

Example: Advertising Multicast Multimedia Sessions Using SAP Listener

Example: Storing IP Multicast Headers

Additional References

Related Documents

MIBs

RFCs

Technical Assistance


Monitoring and Maintaining IP Multicast


This module describes many ways to monitor and maintain an IP multicast network, such as

displaying which neighboring multicast routers are peering with the local router

displaying multicast packet rates and loss information

tracing the path from a source to a destination branch for a multicast distribution tree

displaying the contents of the IP multicast routing table, information about interfaces configured for PIM, the PIM neighbors discovered by the router, and contents of the IP fast-switching cache

clearing caches, tables, and databases

monitoring the delivery of IP multicast packets and being alerted if the delivery fails to meet certain parameters (IP multicast heartbeat)

using session description and announcement protocols and applications to assist the advertisement of multicast multimedia conferences and other multicast sessions and communicating the relevant session setup information to prospective participants (SAP listener support)

storing IP multicast packet headers in a cache and displaying them to find out information such as who is sending IP multicast packets to what groups and any multicast forwarding loops in your network

disabling fast switching of IP multicast in order to log debug messages

Contents

Prerequisites for Monitoring and Maintaining IP Multicast

How to Monitor and Maintain IP Multicast

Configuration Examples for Monitoring and Maintaining IP Multicast

Additional References

Prerequisites for Monitoring and Maintaining IP Multicast

Before performing the tasks in this module, you should be familiar with the concepts described in the "IP Multicast Technology Overview" module.

You must also have enabled IP multicast and have Protocol Independent Multicast (PIM) configured and running on your network. Refer to the "Configuring Basic IP Multicast" module.

Information About Monitoring and Maintaining IP Multicast

IP Multicast Delivery Using IP Multicast Heartbeat

Session Announcement Protocol (SAP)

IP Multicast Delivery Using IP Multicast Heartbeat

The IP multicast heartbeat feature provides a way to monitor the status of IP multicast delivery and be informed when the delivery fails (via Simple Network Management Protocol [SNMP] traps).

IP Multicast Heartbeat

The IP Multicast Heartbeat feature enables you to monitor the delivery of IP multicast packets and to be alerted if the delivery fails to meet certain parameters.

Although you could alternatively use MRM to monitor IP multicast, you can perform the following tasks with IP multicast heartbeat that you cannot perform with MRM:

Generate an SNMP trap

Monitor a production multicast stream

When IP multicast heartbeat is enabled, the router monitors IP multicast packets destined for a particular multicast group at a particular interval. If the number of packets observed is less than a configured minimum amount, the router sends an SNMP trap to a specified network management station to indicate a loss of heartbeat exception.

The ip multicast heartbeat command does not create a heartbeat if there is no existing multicast forwarding state for group in the router. This command will not create a multicast forwarding state in the router. Use the ip igmp static-group command on the router or on a downstream router to force forwarding of IP multicast traffic. Use the snmp-server host ipmulticast command to enable the sending of IP multicast traps to specific receiver hosts. Use the debug ip mhbeat command to debug the Multicast Heartbeat feature.

SNMP Notifications

A key feature of SNMP is the ability to generate notifications from an SNMP agent. These notifications do not require that requests be sent from the SNMP manager. Unsolicited (asynchronous) notifications can be generated as traps or inform requests. Traps are messages alerting the SNMP manager to a condition on the network. Inform requests (informs) are traps that include a request for confirmation of receipt from the SNMP manager. Notifications can indicate improper user authentication, restarts, the closing of a connection, loss of connection to a neighbor router, or other significant events.

Traps are less reliable than informs because the receiver does not send any acknowledgment when it receives a trap. The sender cannot determine if the trap was received. An SNMP manager that receives an inform request acknowledges the message with an SNMP response protocol data unit (PDU). If the manager does not receive an inform request, it does not send a response. If the sender never receives a response, the inform request can be sent again. Thus, informs are more likely to reach their intended destination.

However, traps are often preferred because informs consume more resources in the router and in the network. Unlike a trap, which is discarded as soon as it is sent, an inform request must be held in memory until a response is received or the request times out. Also, traps are sent only once, while an inform may be retried several times. The retries increase traffic and contribute to a higher overhead on the network. Thus, traps and inform requests provide a trade-off between reliability and resources. If it is important that the SNMP manager receives every notification, use inform requests. However, if you are concerned about traffic on your network or memory in the router and you need not receive every notification, use traps.

Session Announcement Protocol (SAP)

Session Announcement Protocol (SAP) listener support is needed to use session description and announcement protocols and applications to assist the advertisement of multicast multimedia conferences and other multicast sessions and to communicate the relevant session setup information to prospective participants.

Sessions are described by the Session Description Protocol (SDP), which is defined in RFC 2327. SDP provides a formatted, textual description of session properties (for example, contact information, session lifetime, and the media) being used in the session (for example, audio, video, and whiteboard) with their specific attributes such as time-to-live (TTL) scope, group address, and User Datagram Protocol (UDP) port number.

Many multimedia applications rely on SDP for session descriptions. However, they may use different methods to disseminate these session descriptions. For example, IP/TV relies on the web to disseminate session descriptions to participants. In this example, participants must know of a web server that provides the session information.

MBONE applications (for example, vic, vat, and wb) and other applications rely on multicast session information sent throughout the network. In these cases, SAP is used to transport the SDP session announcements. SAP Version 2 uses the well-known session directory multicast group 224.2.127.254 to disseminate SDP session descriptions for global scope sessions and group 239.255.255.255 for administrative scope sessions.


Note The Session Directory (SDR) application is commonly used to send and receive SDP/SAP session announcements.


How to Monitor and Maintain IP Multicast

This section contains the following procedures:

Displaying Multicast Peers, Packet Rates, and Loss Information, and Tracing a Path (optional)

Displaying IP Multicast System and Network Statistics (optional)

Clearing IP Multicast Routing Table or Caches (optional)

Monitoring IP Multicast Delivery Using IP Multicast Heartbeat (optional)

Advertising Multicast Multimedia Sessions Using SAP Listener (optional)

Storing IP Multicast Headers (optional)

Disabling Fast Switching of IP Multicast (optional)

Displaying Multicast Peers, Packet Rates, and Loss Information, and Tracing a Path

Monitor IP multicast routing when you want to know which neighboring multicast routers are peering with the local router, what the multicast packet rates and loss information are, or when you want to trace the path from a source to a destination branch for a multicast distribution tree.

SUMMARY STEPS

1. enable

2. mrinfo [host-name | host-address] [source-address | interface]

3. mstat {source-name | source-address} [destination-name | destination-address] [group-name | group-address]

4. mtrace {source-name | source-address} [destination-name | destination-address] [group-name | group-address]

DETAILED STEPS

 
Command or Action
Purpose

Step 1 

enable

Example:

Router> enable

Enables privileged EXEC mode.

Enter your password if prompted.

Step 2 

mrinfo [host-name | host-address] [source-address | interface]

Example:

Router# mrinfo

(Optional) Queries which neighboring multicast routers are "peering" with the local router.

Step 3 

mstat {source-name | source-address} [destination-name | destination-address] [group-name | group-address]

Example:

Router# mstat allsource

(Optional) Displays IP multicast packet rate and loss information.

Step 4 

mtrace {source-name | source-address} [destination-name | destination-address] [group-name | group-address]

Example:

Router# mtrace allsource

(Optional) Traces the path from a source to a destination branch for a multicast distribution tree.

Displaying IP Multicast System and Network Statistics

Display IP multicast system statistics to show the contents of the IP multicast routing table, information about interfaces configured for PIM, the PIM neighbors discovered by the router, contents of the IP fast-switching cache, and the contents of the circular cache header buffer.

SUMMARY STEPS

1. enable

2. ping [group-name | group-address]

3. show ip mroute [group-address | group-name] [source-address | source-name] [type number] [summary] [count] [active kbps]

4. show ip pim interface [type number] [df | count] [rp-address] [detail]

5. show ip pim neighbor [type number]

6. show ip mcache [group-address | group-name] [source-address | source-name]

7. show ip mpacket [group-address | group-name] [source-address | source-name] [detail]

8. show ip pim rp [mapping | metric] [rp-address]

9. show ip rpf {source-address | source-name} [metric]

DETAILED STEPS

 
Command or Action
Purpose

Step 1 

enable

Example:

Router> enable

Enables privileged EXEC mode.

Enter your password if prompted.

Step 2 

ping [group-name | group-address]

Example:

Router# ping cbone-audio

(Optional) Sends an ICMP echo request message to a multicast group address or group name.

Step 3 

show ip mroute [group-address | group-name] [source-address | source-name] [type number] [summary] [count] [active kbps]

Example:

Router# show ip mroute cbone-audio

(Optional) Displays the contents of the IP multicast routing table.

Step 4 

show ip pim interface [type number] [df | count] [rp-address] [detail]

Example:

Router# show ip pim interface ethernet1/0 detail

(Optional) Displays information about interfaces configured for PIM.

Step 5 

show ip pim neighbor [type number]

Example:

Router# show ip pim neighbor

(Optional) Lists the PIM neighbors discovered by the router.

Step 6 

show ip mcache [group-address | group-name] [source-address | source-name]

Example:

Router# show ip mcache

(Optional) Displays the contents of the IP fast-switching cache.

Step 7 

show ip mpacket [group-address | group-name] [source-address | source-name] [detail]

Example:

Router# show ip mpacket smallgroup

(Optional) Displays the contents of the circular cache header buffer.

Step 8 

show ip pim rp [mapping | metric] [rp-address]

Example:

Router# show ip pim rp metric

(Optional) Displays the RP routers associated with a sparse mode multicast group.

Step 9 

show ip rpf {source-address | source-name} [metric]

Example:

Router# show ip rpf 172.16.10.13

(Optional) Displays how the router is doing RPF (that is, from the unicast routing table, DVMRP routing table, or static mroutes). Also displays the unicast routing metric.

Clearing IP Multicast Routing Table or Caches

Clear IP multicast caches and tables to delete entries from the IP multicast routing table, the Auto-RP cache, the IGMP cache, and the caches of Catalyst switches. When these entries are cleared, the information is refreshed by being relearned, thus eliminating any incorrect entries.

SUMMARY STEPS

1. enable

2. clear ip mroute {* | group-name [source-name | source-address] | group-address [source-name | source-address]}

3. clear ip pim auto-rp rp-address

4. clear ip mcache

5. clear ip igmp group [group-name | group-address | interface-type interface-number]

6. clear ip cgmp [interface-type interface-number]

DETAILED STEPS

 
Command or Action
Purpose

Step 1 

enable

Example:

Router> enable

Enables privileged EXEC mode.

Enter your password if prompted.

Step 2 

clear ip mroute {* | group-name [source-name | source-address] | group-address [source-name | source-address]}

Example:

Router# clear ip mroute 224.2.205.42 228.3.0.0

(Optional) Deletes entries from the IP multicast routing table.

Step 3 

clear ip pim auto-rp rp-address

Example:

Router# clear ip pim auto-rp 224.5.6.7

(Optional) Clears the Auto-RP cache.

Step 4 

clear ip mcache

Example:

Router # clear ip mcache

(Optional) Clears the multicast cache.

Step 5 

clear ip igmp group [group-name | group-address | interface-type interface-number]

Example:

Router# clear ip igmp group 224.0.255.1

(Optional) Deletes entries from the IGMP cache.

Step 6 

clear ip cgmp [interface-type interface-number]

Example:

Router# clear ip cgmp

(Optional) Clears all group entries from the caches of Catalyst switches.

Monitoring IP Multicast Delivery Using IP Multicast Heartbeat

SUMMARY STEPS

1. enable

2. configure terminal

3. ip multicast-routing

4. snmp-server host {hostname | ip-address} [traps | informs] [version {1 | 2c | 3 [auth | noauth | priv]}] community-string [udp-port port] [notification-type]

5. snmp-server enable traps ipmulticast

6. ip multicast heartbeat group-address minimum-number window-size interval

DETAILED STEPS

 
Command or Action
Purpose

Step 1 

enable

Example:

Router> enable

Enables privileged EXEC mode.

Enter your password if prompted.

Step 2 

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3 

ip multicast-routing

Example:

Router(config)# ip multicast-routing

Enables IP multicast routing.

Step 4 

snmp-server host {hostname | ip-address} [traps | informs] [version {1 | 2c | 3 [auth | noauth | priv]}] community-string [udp-port port] [notification-type]

Example:

Router(config)# snmp-server host 224.1.0.1 traps public

Specifies the recipient of an SNMP notification operation.

Step 5 

snmp-server enable traps ipmulticast

Example:

Router(config)# snmp-server enable traps ipmulticast

Enables the router to send IP multicast traps.

Step 6 

ip multicast heartbeat group-address minimum-number window-size interval

Example:

Router(config)# ip multicast heartbeat ethernet0 224.1.1.1 1 1 10

Enables the monitoring of the IP multicast packet delivery.

The interval should be set to a multiple of 10 seconds on platforms that use Multicast Distributed Fast Switching (MDFS) because on those platforms, the packet counters are only updated once every 10 seconds. Other platforms may have other increments.

Advertising Multicast Multimedia Sessions Using SAP Listener

Enable SAP listener support when you want to use session description and announcement protocols and applications to assist the advertisement of multicast multimedia conferences and other multicast sessions and to communicate the relevant session setup information to prospective participants.

SUMMARY STEPS

1. enable

2. configure terminal

3. ip sap cache-timeout minutes

4. interface type number

5. ip sap listen

6. end

7. clear ip sap [group-address | "session-name"]

8. show ip sap [group-address | "session-name" | detail]

DETAILED STEPS

 
Command or Action
Purpose

Step 1 

enable

Example:

Router> enable

Enables privileged EXEC mode.

Enter your password if prompted.

Step 2 

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3 

ip sap cache-timeout minutes

Example:

Router(config)# ip sap cache-timeout 600

(Optional) Limits how long a SAP cache entry stays active in the cache.

By default, SAP cache entries are deleted 24 hours after they are received from the network.

Step 4 

interface type number

Example:

Router(config)# interface ethernet 1

Selects an interface that is connected to hosts on which IGMPv3 can be enabled.

Step 5 

ip sap listen

Example:

Router(config-if)# ip sap listen

Enables the Cisco IOS software to listen to session directory announcements.

Step 6 

end

Example:

Router(config-if)# end

Ends the session and returns to EXEC mode.

Step 7 

clear ip sap [group-address | "session-name"]

Example:

Router# clear ip sap "Sample Session"

Deletes a SAP cache entry or the entire SAP cache.

Step 8 

show ip sap [group-address | "session-name" | detail]

Example:

Router# show ip sap 224.2.197.250 detail

(Optional) Displays the SAP cache.

Storing IP Multicast Headers

You can store IP multicast packet headers in a cache and then display them to determine any of the following information:

Who is sending IP multicast packets to what groups

Interpacket delay

Duplicate IP multicast packets (if any)

Multicast forwarding loops in your network (if any)

Scope of the group

UDP port numbers

Packet length

Perform this task if you need any of the information listed above.

SUMMARY STEPS

1. enable

2. configure terminal

3. ip multicast cache-headers [rtp]

4. exit

5. show ip mpacket [group-address | group-name] [source-address | source-name] [detail]

DETAILED STEPS

 
Command or Action
Purpose

Step 1 

enable

Example:

Router> enable

Enables privileged EXEC mode.

Enter your password if prompted.

Step 2 

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3 

ip multicast cache-headers [rtp]

Example:

Router(config)# ip multicast cache-headers

Allocates a circular buffer to store IP multicast packet headers that the router receives.

Step 4 

exit

Example:

Router(config)# exit

Returns to privilege EXEC mode.

Step 5 

show ip mpacket [group-address | group-name] [source-address | source-name] [detail]

Example:

Router# show ip mpacket smallgroup

(Optional) Displays the contents of the circular cache-header buffer.

Disabling Fast Switching of IP Multicast

Disable fast switching if you want to log debug messages, because when fast switching is enabled, debug messages are not logged.

You might also want to disable fast switching, which places the router in process switching, if packets are not reaching their destinations. If fast switching is disabled and packets are reaching their destinations, then switching may be the cause.

Fast switching of IP multicast packets is enabled by default on all interfaces (including generic routing encapsulation [GRE] and DVMRP tunnels), with one exception: It is disabled and not supported over X.25 encapsulated interfaces. The following are properties of fast switching:

If fast switching is disabled on an incoming interface for a multicast routing table entry, the packet is sent at process level for all interfaces in the outgoing interface list.

If fast switching is disabled on an outgoing interface for a multicast routing table entry, the packet is process-level switched for that interface, but may be fast switched for other interfaces in the outgoing interface list.

When fast switching is enabled, debug messages are not logged.

SUMMARY STEPS

1. enable

2. configure terminal

3. interface type number

4. no ip mroute-cache

DETAILED STEPS

 
Command or Action
Purpose

Step 1 

enable

Example:

Router> enable

Enables privileged EXEC mode.

Enter your password if prompted.

Step 2 

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3 

interface type number

Example:

Router(config)# interface ethernet 1

Specifies an interface.

Step 4 

no ip mroute-cache

Example:

Router(config-if)# no ip mroute-cache

Disables fast switching of IP multicast.

Configuration Examples for Monitoring and Maintaining IP Multicast

Example: Displaying Multicast Peers, Packet Rates, and Loss Information, and Tracing a Path

Example: Displaying IP Multicast System and Network Statistics

Example: Monitoring IP Multicast Delivery Using IP Multicast Heartbeat

Example: Advertising Multicast Multimedia Sessions Using SAP Listener

Example: Storing IP Multicast Headers

Example: Displaying Multicast Peers, Packet Rates, and Loss Information, and Tracing a Path

The following is sample output from the mrinfo command:

Router# mrinfo 

192.31.7.37 (labs-allcompany) [version cisco 12.3] [flags: PMSA]: 
192.31.7.37 -> 192.31.7.34 (lab-southwest) [1/0/pim] 
192.31.7.37 -> 192.31.7.47 (lab-northwest) [1/0/pim] 
192.31.7.37 -> 192.31.7.44 (lab-southeast) [1/0/pim] 
131.119.26.10 -> 131.119.26.9 (lab-northeast) [1/32/pim] 

The following is sample output from the mstat command in user EXEC mode:

Router> mstat labs-in-china 172.16.0.1 224.0.255.255 

Type escape sequence to abort. 
Mtrace from 172.16.0.0 to 172.16.0.10 via group 224.0.255.255 
>From source (labs-in-china) to destination (labs-in-africa) 
Waiting to accumulate statistics...... 
Results after 10 seconds: 
Source Response Dest Packet Statistics For Only For Traffic 
172.16.0.0      172.16.0.10 All Multicast Traffic From 172.16.0.0 
| __/ rtt 48 ms Lost/Sent = Pct Rate To 224.0.255.255 
v / hop 48 ms --------------------- -------------------- 
172.16.0.1      labs-in-england 
| ^ ttl 1 
v | hop 31 ms 0/12 = 0% 1 pps 0/1 = --% 0 pps 
172.16.0.2 
172.16.0.3 	 infolabs.com
| ^ ttl 2 
v | hop -17 ms -735/12 = --% 1 pps 0/1 = --% 0 pps 
172.16.0.4 
172.16.0.5      infolabs2.com 
| ^ ttl 3 
v | hop -21 ms -678/23 = --% 2 pps 0/1 = --% 0 pps 
172.16.0.6 
172.16.0.7      infolabs3.com 
| ^ ttl 4 
v | hop 5 ms 605/639 = 95% 63 pps 1/1 = --% 0 pps 
172.16.0.8 
172.16.0.9      infolabs.cisco.com 
| \__ ttl 5 
v \ hop 0 ms 4 0 pps 0 0 pps 
172.16.0.0      172.16.0.10 
Receiver Query Source 

The following is sample output from the mtrace command in user EXEC mode:

Router> mtrace 172.16.0.0 172.16.0.10 239.254.254.254 

Type escape sequence to abort. 
Mtrace from 172.16.0.0 to 172.16.0.10 via group 239.254.254.254 
From source (?) to destination (?) 
Querying full reverse path... 
0 172.16.0.10 
-1 172.16.0.8 PIM thresh^ 0 0 ms 
-2 172.16.0.6 PIM thresh^ 0 2 ms 
-3 172.16.0.5 PIM thresh^ 0 894 ms 
-4 172.16.0.3 PIM thresh^ 0 893 ms 
-5 172.16.0.2 PIM thresh^ 0 894 ms 
-6 172.16.0.1 PIM thresh^ 0 893 ms 

Example: Displaying IP Multicast System and Network Statistics

show ip mroute

The following is sample output from the show ip mroute command for a router operating in sparse mode:

Router# show ip mroute 

IP Multicast Routing Table 
Flags: D - Dense, S - Sparse, B - Bidir Group, s - SSM Group, C - Connected, 
       L - Local, P - Pruned, R - RP-bit set, F - Register flag, 
       T - SPT-bit set, J - Join SPT, M - MSDP created entry, 
       X - Proxy Join Timer Running, A - Candidate for MSDP Advertisement, 
       U - URD, I - Received Source Specific Host Report, Z - Multicast Tunnel, 
       Y - Joined MDT-data group, y - Sending to MDT-data group 
Timers: Uptime/Expires 
Interface state: Interface, Next-Hop, State/Mode 

(*, 224.0.255.3), uptime 5:29:15, RP is 192.168.37.2, flags: SC 
  Incoming interface: Tunnel0, RPF neighbor 10.3.35.1, Dvmrp 
  Outgoing interface list: 
    Ethernet0, Forward/Sparse, 5:29:15/0:02:57 

(192.168.46.0/24, 224.0.255.3), uptime 5:29:15, expires 0:02:59, flags: C 
  Incoming interface: Tunnel0, RPF neighbor 10.3.35.1 
  Outgoing interface list: 
    Ethernet0, Forward/Sparse, 5:29:15/0:02:57 

show ip pim interface

The following is sample output from the show ip pim interface command when an interface is specified:

Router# show ip pim interface Ethernet1/0 

Address          Interface                Ver/   Nbr    Query  DR     DR 
                                          Mode   Count  Intvl  Prior 
172.16.1.4       Ethernet1/0              v2/S   1      100 ms 1      172.16.1.4 

show ip mcache

The following is sample output from the show ip mcache privileged EXEC command when multicast distributed switching (MDS) is in effect:

Router# show ip mcache 

IP Multicast Fast-Switching Cache 
(*, 239.2.3.4), Fddi3/0/0, Last used: mds 
  Tunnel3         MAC Header: 5000602F9C150000603E473F60AAAA030000000800 (Fddi3/0/0) 
  Tunnel0         MAC Header: 5000602F9C150000603E473F60AAAA030000000800 (Fddi3/0/0) 
  Tunnel1         MAC Header: 5000602F9C150000603E473F60AAAA030000000800 (Fddi3/0/0) 

show ip mpacket

The following is sample output from the show ip mpacket command with the group-name argument:

Router# show ip mpacket smallgroup 

IP Multicast Header Cache - entry count:6, next index: 7 
Key: id/ttl timestamp (name) source group 

D782/117 206416.908 (company1.company.com) 192.168.228.10 224.5.6.7 
7302/113 206417.908 (school.edu) 172.16.2.17 224.5.6.7 
6CB2/114 206417.412 (company2.company.com) 172.16.19.40 224.5.6.7 
D782/117 206417.868 (company1.company.com) 192.168.228.10 224.5.6.7 
E2E9/123 206418.488 (company3.com) 239.1.8.10 224.5.6.7 
1CA7/127 206418.544 (company4.company.com) 192.168.6.10 224.5.6.7 

The following is sample output from the show ip pim rp command:

Router# show ip pim rp 

Group:227.7.7.7, RP:10.10.0.2, v2, v1, next RP-reachable in 00:00:48 

show ip pim rp

The following is sample output from the show ip pim rp command when the mapping keyword is specified:

Router# show ip pim rp mapping 

PIM Group-to-RP Mappings 
This system is an RP (Auto-RP) 
This system is an RP-mapping agent 

Group(s) 227.0.0.0/8 
  RP 10.10.0.2 (?), v2v1, bidir 
    Info source:10.10.0.2 (?), via Auto-RP 
         Uptime:00:01:42, expires:00:00:32
Group(s) 228.0.0.0/8 
  RP 10.10.0.3 (?), v2v1, bidir 
    Info source:10.10.0.3 (?), via Auto-RP 
         Uptime:00:01:26, expires:00:00:34 
Group(s) 229.0.0.0/8 
  RP 10.10.0.5 (mcast1.cisco.com), v2v1, bidir 
    Info source:10.10.0.5 (mcast1.cisco.com), via Auto-RP 
         Uptime:00:00:52, expires:00:00:37 
Group(s) (-)230.0.0.0/8 
  RP 10.10.0.5 (mcast1.cisco.com), v2v1, bidir 
    Info source:10.10.0.5 (mcast1.cisco.com), via Auto-RP 
         Uptime:00:00:52, expires:00:00:37 

The following is sample output from the show ip pim rp command when the metric keyword is specified:

Router# show ip pim rp metric 

RP Address      Metric Pref    Metric       Flags   RPF Type   Interface 
10.10.0.2       0              0              L     unicast    Loopback0 
10.10.0.3       90             409600         L     unicast    Ethernet3/3 
10.10.0.5       90             435200         L     unicast    Ethernet3/3 

show ip rpf

The following is sample output from the show ip rpf command:

Router# show ip rpf 172.16.10.13 

RPF information for host1 (172.16.10.13) 
  RPF interface: BRI0 
  RPF neighbor: sj1.cisco.com (172.16.121.10) 
  RPF route/mask: 172.16.0.0/255.255.0.0 
  RPF type: unicast 
  RPF recursion count: 0 
  Doing distance-preferred lookups across tables 

The following is sample output from the show ip rpf command when the metric keyword is specified:

Router# show ip rpf 172.16.10.13 metric 

RPF information for host1.cisco.com (172.16.10.13) 
  RPF interface: BRI0 
  RPF neighbor: neighbor.cisco.com (172.16.121.10) 
  RPF route/mask: 172.16.0.0/255.255.0.0 
  RPF type: unicast 
  RPF recursion count: 0 
  Doing distance-preferred lookups across tables 
  Metric preference: 110 
  Metric: 11 

Example: Monitoring IP Multicast Delivery Using IP Multicast Heartbeat

The following example shows how to monitor IP multicast packets forwarded through this router to group address 244.1.1.1. If no packet for this group is received in a 10-second interval, an SNMP trap will be sent to the SNMP management station with the IP address of 224.1.0.1.

! 
ip multicast-routing 
! 
snmp-server host 224.1.0.1 traps public 
snmp-server enable traps ipmulticast 
ip multicast heartbeat ethernet0 224.1.1.1 1 1 10 

Example: Advertising Multicast Multimedia Sessions Using SAP Listener

The following example enables a router to listen to session directory announcements and changes the SAP cache timeout to 30 minutes.

ip multicast routing 
ip sap cache-timeout 30 
interface loopback 0 
 ip address 10.0.0.51 255.255.255.0 
 ip pim sparse-dense mode 
 ip sap listen 

The following is sample output from the show ip sap command for a session using multicast group 224.2.197.250:

Router# show ip sap 224.2.197.250 

SAP Cache - 198 entries 
Session Name: Session1 
   Description: This broadcast is brought to you courtesy of Name1. 
   Group: 0.0.0.0, ttl: 0, Contiguous allocation: 1 
   Lifetime: from 10:00:00 PDT Jul 4 1999 until 10:00:00 PDT Aug 1 1999 
   Uptime: 4d05h, Last Heard: 00:01:40 
   Announcement source: 128.102.84.134 
   Created by: sample 3136541828 3139561476 IN IP4 128.102.84.134 
   Phone number: Sample Digital Video Lab (555) 555-5555 
   Email: email1 <name@email.com> 
   URL: http://url.com/ 
   Media: audio 20890 RTP/AVP 0 
     Media group: 224.2.197.250, ttl: 127 
     Attribute: ptime:40 
   Media: video 62806 RTP/AVP 31 
     Media group: 224.2.190.243, ttl: 127 

Example: Storing IP Multicast Headers

The following is sample output from the show ip mpacket command for the group named "smallgroup."

Router# show ip mpacket smallgroup 

IP Multicast Header Cache - entry count:6, next index: 7 
Key: id/ttl timestamp (name) source group 

D782/117 206416.908 (company1.company.com) 192.168.228.10 224.5.6.7 
7302/113 206417.908 (school.edu) 172.16.2.17 224.5.6.7 
6CB2/114 206417.412 (company2.company.com) 172.16.19.40 224.5.6.7 
D782/117 206417.868 (company1.company.com) 192.168.228.10 224.5.6.7 
E2E9/123 206418.488 (company3.com) 239.1.8.10 224.5.6.7 
1CA7/127 206418.544 (company4.company.com) 192.168.6.10 224.5.6.7 

Additional References

The following sections provide references related to monitoring and maintaining IP multicast.

Related Documents

Related Topic
Document Title

IP multicast SNMP notifications

"Configuring SNMP Support" module

IP multicast commands: complete command syntax, command mode, defaults, usage guidelines, and examples

Cisco IOS IP Multicast Command Reference


MIBs

MIBs
MIBs Link

CISCO-IPMROUTE-MIB

MSDP-MIB

IGMP-STD-MIB

To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:

http://www.cisco.com/go/mibs


RFCs

RFCs
Title

RFC 2934

Protocol Independent Multicast for IPv4 MIB


Technical Assistance

Description
Link

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http://www.cisco.com/public/support/tac/home.shtml