Description                                                    Configure a group of tagged Ethernet interfaces for forwarding Bridge Protocol Data Units (BPDUs). BPDU forwarding groups enable you to use the ACOS device in a network that runs Spanning Tree Protocol (STP).

A BPDU forwarding group is a set of tagged Ethernet interfaces that will accept and broadcast STP BPDUs among themselves. When an interface in a BPDU forwarding group receives an STP BPDU (a packet addressed to MAC address 01-80-C2-00-00-00), the interface broadcasts the BPDU to all the other interfaces in the group.

Syntax                                                                  [no] bpdu-fwd-group group-num

Replace group-num with the BPDU forwarding group number (1-8).

If the ACOS device is a member of an aVCS virtual chassis, specify the group number as follows: DeviceID/group-num

This command changes the CLI to the configuration level for the BPDU forwarding group, where the following command is available.

[no] ethernet portnum [to portnum] [ethernet portnum]

This command enables you to specify the ethernet interfaces you want to add to the BPDU forwarding group.

Default                                                                None

Mode                                                                   Configuration mode

Usage                                                                  This command is specifically for configuring VLAN-tagged interfaces to accept and forward BPDUs.

Rules for trunk interfaces:

     BPDUs are broadcast only to the lead interface in the trunk.

     If a BPDU is received on an Ethernet interface that belongs to a trunk, the BPDU is not broadcast to any other members of the same trunk.

Example                                                            The following commands create BPDU forwarding group 1 containing Ethernet ports 1-3, and verify the configuration:

ACOS(config)# bpdu-fwd-group 1

ACOS(config-bpdu-fwd-group:1)# ethernet 1 to 3

ACOS(config-bpdu-fwd-group:1)# show bpdu-fwd-group

BPDU forward Group 1 members: ethernet 1 to 3

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