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Changing global ip multicast parameters, Defining the maximum number of dvmrp cache entries – Brocade Multi-Service IronWare Multicast Configuration Guide (Supporting R05.6.00) User Manual

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Multi-Service IronWare Multicast Configuration Guide

53-1003032-02

Changing global IP multicast parameters

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Changing global IP multicast parameters

The following sections apply to PIM-DM, PIM-SM, IGMP, and DVMRP.

Concurrent support for multicast routing
and snooping

Multicast routing and multicast snooping instances work concurrently on the same device. For
example, you can configure PIM routing on certain VEs interfaces and snooping on other VEs or
VLANs. The limitation is that either multicast snooping or routing can be enabled on a VE interface
or VLAN, but not on both. This is because all of the multicast data and control packets (IGMP, PIM)
received on the snooping VLAN are handled by multicast snooping and do not reach the multicast
routing component. Similarly, any multicast data or control packets received on a VE interface
enabled with PIM or DVMRP routing are handled by the PIM or DVMRP routing component and are
not seen by the IGMP or PIM snooping component.

The following considerations apply when configuring concurrent operation of Multicast Routing and
Snooping.

1. Either multicast snooping or routing can be enabled on a VE or VLAN but not both.

2. Snooping can be enabled globally (ip multicast active | passive) as can multicast routing (ip

multicast-routing).

3. The global snooping configuration is inherited by all current VLANs that are not enabled for

multicast routing.

4. The global snooping configuration is also inherited by all new VLANs. Enabling multicast

routing on a newly created VLAN or VE automatically disables snooping on the VLAN or VE.

5. When a VLAN-level snooping is configured, it is displayed.

Defining the maximum number of DVMRP
cache entries

You can use the following run-time command to define the maximum number of repeated DVMRP
traffic being sent from the same source address and being received by the same destination
address. The maximum number of multicast cache entries for DVMRP can be defined for the
default VRF using the following command.

Brocade(config)# router dvmrp

Brocade(config-dvmrp-router)# max-mcache 500

Syntax: [no] max-mcache num

The num variable specifies the maximum number of multicast cache entries for DVMRP. If not
defined by this command, the maximum value is determined by available system resources.

The maximum number of multicast cache entries for DVMRP for a specified Virtual Routing
Instance (VRF) can be defined using the following command.

Brocade(config)# router dvmrp vrf vpn1

Brocade(config-dvmrp-router-vrf-vpn1)# max-mcache 500

Syntax: [no] router dvmrp [vrf vrf-name]