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Catalyst 3550 Multilayer Switch Software Configuration Guide
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Chapter24 Configuring IP Multicast Routi ng Configuring Optional Multicast Routing Features
Configuring sdr Listener Support
The MBONE is the small subset of Internet routers and hosts that are interconnected and capable of
forwarding IP multicast traffic. Other interesting multimedia content is often broadcast over the
MBONE. Before you can join a multimedia session, you need to know what multicast group address and
port are being used for the session, when the session is going to be active, and what sort of applications
(audio, video, and so forth) are required on your workstation. The MBONE Session Dir ectory version 2
(sdr) tool provides this information. This freeware application ca n be downloaded from several sites on
the World Wide Web, one of which is http://www.video.ja.net/mice/index.html.
SDR is a multicast application that listens to a well-known multicast group address and port for Session
Announcement Protocol (SAP) multicast packets from SAP clients, which announce their conference
sessions. These SAP packets contain a session description, the time the session is active, its IP multicast
group addresses, media format, contact person, and other information about the advertised multimedia
session. The information in the SAP packet is displayed in the SDR Session Announcement window.

Enabling sdr Listener Support

By default, the multilayer switch does not listen to session directory advertisements.
Beginning in privileged EXEC mode, follow these steps to enable the switch to join the default session
directory group (224.2.127.254) on the interface and listen to sessio n d ir ector y ad ver tise men ts:
To disable sdr support, use the no ip sdr listen interface configuration command.

Limiting How Long an sdr Cache Entry Exists

By default, entries are never deleted from the sdr cache. You can limit how long the en try remains active
so that if a source stops advertising SAP information, old advertisements are not needlessly kept.
Beginning in privileged EXEC mode, follow these steps to limit how long an sdr cache entry stays active
in the cache:
Command Purpose
Step1 configure terminal Enter global configuration mode.
Step2 interface interface-id Enter interface configuration mode, and specify the interface to be
enabled for sdr.
Step3 ip sdr listen Enable sdr listener support.
Step4 end Return to privileged EXEC mode.
Step5 show running-config Verify your entries.
Step6 copy running-config startup-config (Optional) Save your entries in the configuration file.
Command Purpose
Step1 configure terminal Enter global configuration mode.
Step2 ip sdr cache-timeout minutes Limit how long an sdr cache entry stays active in the cache.
By default, entries are never deleted from the cache.
For minutes, specify a number from 1 t o 429 496 7295 .