Protocol-Independent Multicast (PIM), routers maintain forwarding tables that they use to forward multicast datagrams.

Packets delivered to members of the multicast group are identified by a single multicast group address. Any host, regardless of whether it is a member of a group, can send to a group. However, only the members of a group receive the message. Membership in an IP multicast group is dynamic; hosts can join and leave at any time. There is no restriction on the location or number of members in a multicast group. A host can be a member of more than one multicast group at a time.

IGMP Snooping

A traditional Layer-2 switch is unable to determine which end stations on the LAN are interested in which multicast groups. To avoid unnecessary flooding, the switch may use IGMP Snooping. That means the switch listens to IGMP messages to learn which ports want multicast traffic from which multicast groups. The switch inserts the correct Ethernet multicast address into the forwarding table for the ports where an end station has joined a multicast group.

4.5.1 Configuring IP Multicast Traffic Management

The Multicast Traffic Management Menu allows you to set up group transmission. To access the Multicast Traffic Management Menu, type c in the Configuration Menu. You will see a screen similar to the following:

IntraCore

3524 IP Multicast Traffic Management Menu

VID: [01]

IP Multicast Forwarding Database

 

--------------------------------

 

IP Multicast Address Count

: 0

 

IGMP Status

 

: [Disabled]

 

IGMP Proxy Report Forward

: [Disabled]

 

--------

-------- --------

--XXXXXX --------

-------- -------- --XXXXXX

<Cmd>

<Description>

 

 

i

Toggle IGMP Enable/Disable

 

x

Toggle IGMP Proxy Report Forward Enable/Disable

m

IP Multicast Forwarding Database Configuration

d

Display Group Addresses

 

a

Display Group Addresses in All VLAN

 

q

Return to previous menu

 

Command>

 

 

 

 

S)elect VLAN

N)ext VLAN

P)rev VLAN

 

 

 

 

 

 

Enabling and Disabling IGMP Snooping

To enable or disable IGMP Snooping on the switch, from the Multicast Traffic Management Menu, type i to toggle the status of IGMP Snooping.

Displaying a Summary of Group Addresses

To display a list of multicast group addresses for the current VLAN, from the IP Multicast Traffic Management Menu, type d. You will see a screen similar to the following:

Multicast IP Addr

Action

+--------------------

+--------------------

+

xxx.xxx.xxx.xxx

 

IGMP

 

xxx.xxx.xxx.xxx

 

IGMP

 

xxx.xxx.xxx.xxx

 

IGMP

 

xxx.xxx.xxx.xxx

 

Mgm Action

 

End of Summary,

Quit

 

 

To display a list of all multicast group addresses, from the IP Multicast Traffic Management Menu, type a. You will see a screen similar to the following:

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Asante Technologies 3500 Series user manual Configuring IP Multicast Traffic Management, Igmp Snooping