Interfaces To Layer 3 Protocols; Igmp Snooping - Allied Telesis AT-8800 SERIES User Manual

Layer 2 Switching
Software Release 2.6.1
C613-02039-00 REV A
Table 20: Parameters in the output of the SHOW STP COUNTER command
Parameter
Config BPDU length
TCN BPDU length
RST BPDU length
If necessary, all the STP configuration that users have created on the switch can
be removed, so that all STPs except the default STP are destroyed, and all other
defaults are restored, using the command:
PURGE STP
The PURGE STP command should be used with caution, and generally only
before major reconfiguration of the switch, as it removes all STP configuration
entered on the switch.

Interfaces to Layer 3 Protocols

Interfaces can be configured to VLANs for IP, IPX and Appletalk routing
protocols in the same way that other interfaces are created for other interface
types. Concatenate VLAN with the VID of the VLAN giving VLANn, for
instance:
INTERFACE=VLAN3

IGMP Snooping

IGMP (Internet Group Management Protocol) is used by IP hosts to report their
multicast group memberships to routers and switches. IP hosts join a multicast
group to receive broadcast messages directed to the multicast group address.
IGMP is an IP-based protocol and uses IP addresses to identify both the
multicast groups and the host members. For a VLAN-aware devices, this
means multicast group membership is on a per-VLAN basis. If at least one port
in the VLAN is a member of a multicast group, by default multicast packets
will be flooded onto all ports in the VLAN.
IGMP snooping enables the switch to forward multicast traffic intelligently on
the switch. The switch listens to IGMP membership reports, queries and leave
messages to identify the switch ports that are members of multicast groups.
Multicast traffic will only be forwarded to ports identified as members of the
specific multicast group.
IGMP snooping is performed at Layer 2 on VLAN interfaces automatically. By
default, the switch will only forward traffic out those ports with multicast
listeners, therefore it will not act as a simple hub and flood all multicast traffic
Meaning
The number of Configuration BPDUs that had an incorrect
length.
The number of Topology Change Notification BPDUs that
had an incorrect length.
The number of Rapid Spanning Tree BPDUs that had an
incorrect length (RAPID mode only).
97