Switches - Juniper JUNOS OS 10.4 - FOR EX REV 1 Manual

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Copyright © 2010, Juniper Networks, Inc.
Peer STP applications running on the switch interfaces use BPDUs to communicate.
Ultimately, the exchange of BPDUs determines which interfaces block traffic and which
interfaces become root ports and forward traffic.
However, a user bridge application running on a PC can also generate BPDUs. If these
BPDUs are picked up by STP applications running on the switch, they can trigger STP
miscalculations, and those miscalculations can lead to network outages.
Enable BPDU protection on switch interfaces connected to user devices or on interfaces
on which no BPDUs are expected, such as edge ports. If BPDUs are received on a protected
interface, the interface is disabled and stops forwarding frames.
Not only can you configure BPDU protection on a switch with a spanning tree, but also
on a switch without a spanning tree. This type of topology typically consists of a non-STP
switch connected to an STP switch through a trunk interface.
To configure BPDU protection on a switch with a spanning tree, include the
statement at the [
bpdu-block-on-edge
To configure BPDU protection on a switch without a spanning tree, include the
statement at the [ edit ethernet-switching-options interface interface-name
level.
After the misconfiguration that triggered the BPDUs being sent to an interface is fixed in
the topology, the interface can be unblocked in one of two ways:
If the disable-timeout statement has been included in the BPDU configuration, the
interface automatically returns to service after the timer expires.
Use the operational mode command
Disabling the BPDU protection configuration does not unblock the interface.
Example: Configuring BPDU Protection on STP Interfaces to Prevent STP
Miscalculations on EX Series Switches on page 1795
Example: Configuring BPDU Protection on non-STP Interfaces to Prevent STP
Miscalculations on EX Series Switches on page 1799
Understanding Loop Protection for STP, RSTP, VSTP, and MSTP on EX Series Switches
on page 1758
Understanding Root Protection for STP, RSTP, VSTP, and MSTP on EX Series Switches
on page 1759
Understanding MSTP for EX Series Switches on page 1755
Understanding RSTP for EX Series Switches on page 1753
Understanding STP for EX Series Switches on page 1751
Understanding VSTP for EX Series Switches on page 1760
Chapter 70: Spanning-Tree Protocols—Overview
( | |
edit protocols stp mstp
clear ethernet-switching bpdu-error
)] hierarchy level.
rstp
bpdu-block
] hierarchy
.
1757