Example: Configuring Bpdu Protection On Interfaces To Prevent Stp Miscalculations On Ex Series Switches - Juniper EX9200 Features Manual

Spanning-Tree Protocols Feature Guide for EX9200 Switches
Example: Configuring BPDU Protection on Interfaces to Prevent STP Miscalculations
on EX Series Switches
Requirements
224
Example: Configuring Root Protection to Enforce Root Bridge Placement in Spanning
Trees on EX Series Switches
Understanding BPDU Protection for STP, RSTP, and MSTP on EX Series Switches on
page 217
NOTE: This example uses Junos OS for EX Series switches with support for
the Enhanced Layer 2 Software (ELS) configuration style. If your switch runs
software that does not support ELS, see Example: Configuring BPDU Protection
on Interfaces to Prevent STP Miscalculations on EX Series Switches. For ELS
details, see Getting Started with Enhanced Layer 2 Software.
Spanning-tree protocols support loop-free network communication through the exchange
of a special type of frame called a bridge protocol data unit (BPDU). However, when
BPDUs generated by spanning-tree protocols are communicated to devices on which
spanning-tree protocols are not configured, these devices recognize the BPDUs, which
can lead to network outages. You can, however, enable BPDU protection on switch
interfaces to prevent BPDUs generated by spanning-tree protocols from passing through
those interfaces. When BPDU protection is enabled, an interface shuts down when any
incompatible BPDU is encountered, thereby preventing the BPDUs generated by
spanning-tree protocols from reaching the switch.
This example configures BPDU protection on STP switch downstream interfaces that
connect to two PCs:
Requirements on page 224
Overview and Topology on page 225
Configuration on page 226
Verification on page 227
This example uses the following software and hardware components:
One EX Series switch in an RSTP topology
One EX Series switch that is not in any spanning-tree topology
Junos OS Release 13.2X50-D10 or later or later for EX Series switches
Before you configure the interfaces on Switch 2 for BPDU protection, be sure you have:
Ensured that RSTP is operating on Switch 1.
Disabled RSTP on Switch 2
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