HP ProCurve 7000dl Series Basic Management And Configuration Manual page 573

Bridging—Transmitting Non-IP Traffic or Merging Two Networks
Configuring Spanning Tree
To enable Frame Relay and ATM subinterfaces to act as edge ports, move to
the logical interface configuration mode context and enter:
Syntax: spanning-tree edgeport
When the global setting defines all interfaces as edge ports by default, use the
no form of the command to disable the edgeport setting on the individual
subinterface.
You should consider implementing the BPDU guard on edge ports. End
devices should not participate in the spanning tree. However, a user running
software that implements STP or RSTP can join spanning tree and disrupt the
network. If the default priority setting on the user software is low, the end
device can even become the root. The BPDU guard prevents the router
interface from receiving BPDU messages from the end device. It also prevents
the interface from being connected to an unauthorized switch.
You configure the BPDU guard on an individual logical interface with this
command:
Syntax: spanning-tree bpduguard [enable | disable]
Use the enable option to activate the guard.
You can also configure the BPDU guard on all interfaces from the global
configuration mode context:
Syntax: spanning-tree edgeport bpduguard default
You can then override this setting for an individual interface by entering this
form of the command from the interface configuration mode context:
ProCurve(config-fr 1.1)# spanning-tree bpduguard disable
Configuring an Interface for a Point-to-Point Versus a Shared
Connection. RSTP must know whether an interface uses a point-to-point or
shared connection to implement sync.
Point-to-point interfaces use sync to rapidly transition from discarding to
forwarding frames. One interface sends a BPDU proposing that it become the
neighbor's designated switch. If the neighbor agrees, both interfaces become
immediately active.
Interfaces on shared media, which reach more than one neighbor on the same
connection, cannot exchange sync BPDUs to activate a connection.
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