Using Igmp Traffic Filtering; Igmp Software Requirements; Default Igmp Filter Configuration - Cisco WS-C2950SX-48-SI Configuration Manual

Filtering IGMP Traffic
If a port is set to permit, only matching IPs are forwarded; all others are dropped. If a filtering action
permits a particular IGMP packet, only that packet is forwarded for processing, and all others are
dropped.
If a port is set to deny, matched IPs are dropped; all others are forwarded. If the filtering action causes
an IGMP packet to be dropped, the switch port requesting the stream of IP multicast traffic cannot
receive IP multicast traffic for that group.
Note IGMP filtering actions do not direct IP multicast traffic forwarding. For example, IGMP filtering does
not know if CGMP is used to allow IP multicast traffic forwarding.
The following sections describe IGMP traffic filtering usage, requirements, and configurations.

Using IGMP Traffic Filtering

You can use IGMP filters in video service deployment of Ethernet to the Home (ETTH).
IGMP transmits video channels as IP multicast traffic using MPEG encoding. In access switches, filters
specify which video channels (multicast addresses) are allowed to be received by every customer.
In ETTH, a typical access switch has two high-speed uplink ports. The other ports are user ports, each
connected to a different end subscriber who has a box that generates IGMP report and leave messages.
You can define which channels (IP multicast addresses) to monitor and the minimum monitoring
interval. If an end subscriber is looking at a channel for more than the minimum monitoring interval, an
entry is created in a monitoring table. IGMP monitoring creates statistics about channel changing
patterns of which channels are viewed when and for how long.

IGMP Software Requirements

IGMP requires software release 7.1(1) or later releases and has the following physical restrictions for
filtering through software:
•
•
•

Default IGMP Filter Configuration

Table 15-3
Table 15-3 IGMP Default Configuration
Feature
IGMP filtering
IGMP enable state
IGMP match-action state
Catalyst 4500 Series, Catalyst 2948G, Catalyst 2980G Switches Software Configuration Guide
15-18
A threshold of 1024 profiles available on the Catalyst 4500 series switch
A limit of 512 Class D multicast IP addresses which can be filtered in all profiles
One (1) profile per port
shows the default IGMP traffic filter configuration.
Default Value
None
Disabled
Deny
Chapter 15 Configuring Multicast Services
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Release 8.1
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