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Ethernet Card Software Feature and Configuration Guide, R7.2
January 2009
Chapter 17 Configuring Cisco Proprietary Resilient Packet Ring
Configuring Shortest Path and Topology Discovery
Configuring Shortest Path and Topology Discovery
To enable and configure shortest path and topology discovery, perform the following procedure,
beginning in global configuration mode:

Monitoring and Verifying Topology Discovery and Shortest Path Load

Balancing

After configuring topology discovery, you can monitor the status using the global command show spr
topology 1 to display the Cisco proprietary RPR topology information. Example 17-9 illustrates the
output of this commands.
Example 17-9 Output of show spr topology command
Router> show spr topology 1
***** ML-RPR Topology Map **************
Local Station Topology Info
Node Id : 40
West Span neighbor : 0
East Span neighbor : 0
Ring Topology: OPEN (UNSTABLE)
Advertised Protection requests:
ringlet0: IDLEringlet1: IDLE
Active Edges:
ringlet0: NO ringlet1: NO
Sequence Number: 0
=======================================================================
East Interface: POS1 West Interface: POS0
Number of nodes on east: 2
Number of nodes on west: 2
Active Topology Defects:
1. Topology Instability
Hops (POS 0) Node Id Edge W/E Request W/E
4 20 NO/NO IDLE/IDLE
6 40 NO/NO IDLE/IDLE
Hops (POS 1) Node Id Edge W/E Request W/E
2 20 NO/NO IDLE/IDLE
6 40 NO/NO IDLE/IDLE
Command Purpose
Step 1 Router# interface spr1 Activates interface configuration mode to
configure the POS interface.
Step 2 Router(config-if)# spr topology discovery Enables topology discovery on Cisco proprietary
RPR.
Step 3 Router(config-if)# spr load-balance
shortest-hop
Configures shortest path load-balancing for
Layer 2 unicast packets being added to the ring.
Step 4 Router(config-if)# no shutdown Enables the interface by preventing it from
shutting down.
Step 5 Router(config)# end Returns to privileged EXEC mode.
Step 6 Router# copy running-config startup-config (Optional) Saves configuration changes to the
TCC2/TCC2P flash database.