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This chapter describes IP multicast tools that allow you to trace a multicast path or test a multicast environment. It includes the following sections:
For a complete description of the commands in this chapter, refer to the "IP Multicast Tools Commands" chapter in the Cisco IOS IP and IP Routing Command Reference publication.
Use the following commands in EXEC mode to monitor IP multicast routers, packets, and paths:
| Command | Purpose |
|---|---|
Router# mrinfo [hostname | address] [source-address | interface] | Query a multicast router about which neighboring multicast routers are peering with it. |
Router# mstat source [destination] [group] | Display IP multicast packet rate and loss information. |
Router# mtrace source [destination][group] | Traces the path from a source to a destination branch for a multicast distribution tree for a given group. |
The Multicast Routing Monitor (MRM) feature is a management diagnostic tool that provides network fault detection and isolation in a large multicast routing infrastructure. It is designed to notify a network administrator of multicast routing problems in near real time.
MRM has three components that play different roles: the Manager, the Test Sender, and the Test Receiver.
You create a test based on various test parameters, name the test, and start the test. The test runs in the background and the command prompt returns.
If the Test Receiver detects an error (such as packet loss or duplicate packets), it sends an error report to the router configured as the Manager. The Manager immediately displays the error report. Also, by issuing a certain show command, you can see the error reports, if any. You then troubleshoot your multicast environment as normal, perhaps using the mtrace command from the source to the Test Receiver. If the show command displays no error reports, the Test Receiver is receiving test packets without loss or duplicates from the Test Sender.
Cisco's implementation of MRM supports Internet-Draft of Multicast Routing Monitor (MRM), IETF, March 1999.
The benefits of the MRM feature are as follows:
You must make sure the underlying multicast forwarding network being tested has no access lists or boundaries that deny the MRM data and control traffic. Specifically, consider the following:
Perform the following tasks to configure and use the MRM feature:
You must configure a Test Receiver on a router or host. To do so, use the following commands beginning in global configuration mode:
| Command | Purpose | |
|---|---|---|
Step1 | Router(config)# interface type number | Specifies an interface. |
Step2 | Router(config-if)# ip mrm test-receiver | Configures the interface to be a Test Receiver. |
Step3 | Router(config)# ip mrm accept-manager {access-list-name | access-list-number} | Optionally, specifies that the Test Receiver can accept status report requests only from Managers specified by the access list. |
To use MRM on test packets instead of actual IP multicast traffic, you must also use the following commands to configure a Test Sender on a different router or host from where you configured the Test Receiver. Use the following command beginning in globacl configuration mode:
| Command | Purpose | |
|---|---|---|
Step1 | Router(config)# interface type number | Specifies an interface. |
Step2 | Router(config-if)# ip mrm test-sender | Configures the interface to be a Test Sender. |
Step3 | Router(config)# ip mrm accept-manager
{access-list-name | access-list-number}
| Optionally, specifies that the Test Sender can accept status report requests only from Managers specified by the access list. |
If you have more than one multicast group to monitor, you could configure an interface that is a Test Sender for one group and a Test Receiver for another group.
Figure 60 illustrates an environment where the router on the left is the Test Sender for Group A and the Test Receiver for Group B.
In this case, you would configure the Test Sender in Group B and the Test Receiver in Group A separately, as already discussed. You would also configure the following commands on the router or host that belongs to both Group A and Group B (in the upper left of Figure 60).
| Command | Purpose | |
|---|---|---|
Step1 | Router(config)# interface type number | Specifies an interface. |
Step2 | Router(config-if)# ip mrm test-sender-receiver | Configures the interface to be a Test Sender for one group and a Test Receiver for another group. |
Step3 | Router(config)# ip mrm accept-manager
{access-list-name | access-list-number}[test-sender |
test-receiver]
| Optionally, specifies that the Test Sender or Test Receiver can accept status report requests only from Managers specified by the access list. By default, the command applies to both the Sender and Receiver. Because this device is both, you might need to specify that the restriction applies to only the Sender or only the Receiver. |
You must configure a router as a Manager in order for MRM to function; a host cannot be a Manager. Perform the following steps:
| Command | Purpose | |
|---|---|---|
Step1 | Router(config)# ip mrm manager test-name | |
Step2 | Router(config-mrm-manager)# manager type number group ip-address | Specifies which interface on the router is the Manager, and specifies the multicast group address the Test Receiver will listen to. |
Step3 | Router(config-mrm-manager)# beacon [interval seconds][holdtime seconds] [ttl hops] | Changes the frequency, duration, or scope of beacon messages that the Manager sends to the Test Sender and Test Receiver. |
Step4 | Router(config-mrm-manager)# udp-port [test-packet port-number] [status-report port-number] | |
Step5 | Router(config-mrm-manager)# senders {access-list-number | access-list-name}[packet-delay milliseconds][rtp | udp] [target-only | all-multicasts | all-test-senders] | Configures Test Sender parameters. |
Step6 | Router(config-mrm-manager)# receivers {access-list-name | access-list-number} [sender-list {access-list-name | access-list-number} [packet-delay]] [window seconds] [report-delay seconds] [loss percentage] [no-join] [monitor | poll] |
Use the show ip mrm manager command to display the Manager configuration.
Use the following command in EXEC mode to start and subsequently stop your MRM test.
| Command | Purpose |
|---|---|
Router# mrm test-name {start | stop} | Starts or stops the MRM test. |
When the test begins, the Manager sends a unicast control packet to the Test Sender and Test Receiver, and then the Manager starts sending beacons. The Test Sender and Test Receiver send acknowledgments to the Manager and begin sending or receiving test packets. If an error occurs, the Test Receiver sends an error report to the Manager, which immediately displays the report.
You cannot change the Manager parameters while the test is in progress.
| Command | Purpose |
|---|---|
Router# clear ip mrm status-report [ip-address] | Clears the status report cache buffer. |
Router# show ip mrm interface [interface-unit] | |
Router# show ip mrm manager [test-name] | Displays MRM test information. |
Router# show ip mrm status-report [ip-address] | Displays the status reports (errors) in the circular cache buffer. |
Figure 61 illustrates a Test Sender, a Test Receiver, and a Manager in an MRM environment. The partial configurations for the three devices follow the figure.
Test Sender
interface Ethernet 0 ip mrm test-sender
Test Receiver
interface Ethernet 0 ip mrm test-receiver
Manager
ip mrm manager test1 manager Ethernet 1 group 239.1.1.1 senders 1
receivers 2 sender-list 1 ! access-list 1 permit 10.1.1.2 access-list 2 permit 10.1.4.2
Posted: Wed Jul 26 18:43:14 PDT 2000
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