- Allied Telesis, Inc Switch Specification Manual

Protecting the network

Create A Secure Network With Allied Telesis Managed Layer 3 Switches 8

IGMP filtering

IGMP filtering lets you dictate exactly which multicast

groups a specific port can receive, by creating a filter list and

applying it to the port. Different ports may have different

filter lists applied to them.

If desired, you can select the type of message to filter. By

default, filters apply to IGMP reports. You can create extra

entries to also filter queries (type=query) and leave

messages (type=leave).

Configuration

For each port:

1. Work out which groups you want users on the port to be able to join.

2. Create an IGMP filter.

3. Create entries to allow the appropriate groups (action=include).

Note: The order of entries in a filter is important. When IGMP tries to match a message

to a filter, it performs a linear search of the filter to find a matching entry. It tries

each entry in turn, and stops processing the filter after the first match it finds.

4. Create an entry to block all groups (action=exclude). Give this entry a higher entry

number than entries for the included groups.

5. Apply the filter to the port.

Example

To stop the user attached to port

from joining any group except 224.

create igmp filter=1

add igmp filter=1 entry=1 group=224.12.13.14 action=include

add igmp filter=1 entry=2 group=224.0.0.0-239.255.255.255

action=exclude

set switch port=1 igmpfilter=1

IGMP throttling

Throttling limits the number of multicast groups that an

individual port can join.

To limit port 2 to a total of 6 groups:

set switch port=2 igmpmaxgroup=6

igmpaction=replace

Products

All switches listed on page 2

that support 2.7.5 or later