Configuring Advanced

Features

 

 

Configuring Advanced Features

Multimedia Traffic Control with IP Multicast (IGMP)

 

Enabling IGMP allows the ports to detect IGMP queries and report packets

 

and manage IP multicast traffic through the switch. If no other querier is

 

detected, the switch will then also function as the querier. (If you need to

 

disable the querier feature, you can do so through the IGMP configuration

 

MIB. Refer to “Changing the Querier Configuration Setting” on page 9-97.)

 

 

N o t e

IGMP configuration on the Switch 2512/2524 operates at the VLAN context

 

level. If you are not using VLANs, then configure IGMP in VLAN 1 (the default

 

VLAN) context. IGMP requires an IP address and subnet mask for any VLAN

 

used for IGMP traffic. If the switch relies on DHCP or Bootp to acquire an IP

 

address, ensure that an IP addressing has been assigned to the appropriate

 

VLANs by using show ip or by viewing the menu interface “Management

 

Address Information” screen (page 10-6).

 

In order for IGMP service to take effect, an IP address must be configured and

 

active on the VLAN in which you want IGMP to operate. If the only VLAN on

 

the switch is the default VLAN (VLAN ID, or VID, of “1”), then you must

 

configure an IP address for VLAN 1. If multiple VLANs are configured, you

 

must configure an IP address for the VLAN(s) in which you want to implement

 

IGMP. Refer to “IP Configuration” on page 5-3.

 

 

IGMP Operating Features

In the factory default configuration, IGMP is disabled. If multiple VLANs are not configured, you must configure IGMP on the default VLAN (DEFAULT_VLAN; VID = 1). If multiple VLANs are configured, you must configure IGMP on a per-VLAN basis. When you use either the CLI or the web browser interface to enable IGMP on the switch or a VLAN, the switch forwards IGMP traffic only to ports belonging to multicast groups. Using the console enables these additional options:

■ Forward with High Priority. Disabling this parameter (the default) causes the switch or VLAN to process IP multicast traffic, along with other traffic, in the order received (normal priority). Enabling this parameter causes the switch or VLAN to give a higher priority to IP multicast traffic than to other traffic.

■ Auto/Blocked/Forward: You can use the console to configure individual ports to any of the following states:

• Auto (the default): Causes the switch to interpret IGMP packets and to filter IP multicast traffic based on the IGMP packet information for ports belonging to a multicast group. This means that IGMP traffic will be forwarded on a specific port only if an IGMP host or multicast router is connected to the port.

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