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Superblade Network Modules User’s Manual
6-28
• Authorization – This displays the authentication status of an enabled port. It
includes the following status:
• In Progress – This indicates that the authentication is still in progress. Traffic is not
forwarded before authentication is verified.
• Yes indicates the port access is authorized.
• No indicates the port access is not authorized.
• N/A means no authentication required.
6-12 IGMP Snooping
IP multicast is often used to distribute video/audio multimedia data over the network.
The layer 2 switch will flood multicast frames to all of ports of switch, which wastes a lot
of unnecessary network bandwidth. IGMP is a standard defined in RFC1112 for IGMPv1
and in RFC2236 for IGMPv2. IGMP specifies how a host can register a router in order to
receive specific multicast traffic. A layer 3 switch usually supports Internet Group
Management Protocol (IGMP) to manage multicast groups by sending and processing
IGMP packets. To prevent the unnecessary flooding, the gigabit layer 2 switch can
enable the
IGMP snooping function to control how IP multicast packets are forwarded to
required ports by monitoring IGMP queries and response packets generated by layer 3
switches or the IGMP querier.
Currently, the gigabit switch supports IGMP snooping for IGMP v1/v2 packets. In the
real network setup, the switch is seated between the Multicast Router/Server and the
host. The Multicast Router/Server will periodically send an IGMP v2 query packet and
the host will respond with an IGMP v2 report packet if the host is in the same multicast
group. When the host wants to go away, it can send an IGMP v2 Leave packet. The
switch will remove the connected port number from the multicast group entry of a table.
If the host is just silently removed, then the switch will clean it from table when the timer
expires.
Figure 6-21 shows the IGMP S
NOOPING
configuration screen. Table 6-8 describes each
configuration item.