17-28
Ethernet Card Software Feature and Configuration Guide, R7.2
January 2009
Chapter 17 Configuring Cisco Proprietary Resilient Packet Ring
Understanding Cisco Proprietary RPR Link Fault Propagation
Step 23 If the ML-Series card in the new node is to be deleted in CTC and physically removed, d o so now. Refer
to the “Install Cards and Fiber-Optic Cable” chapter of the Cisco ONS 15454 Procedure Guide or the
“Install Cards and Fiber-Optic Cable” chapter of the Cisco ONS 15454 SDH Procedure Guide for
procedures for installing cards in ONS nodes.
Step 24 Build an STS circuit with a circuit state of IS from the available POS port on Adjacent Node 1 to the
available POS port on Adjacent Node 2, as shown in Figure 17-12. For detailed steps on building the
circuit, see “Configuring CTC Circuits for Cisco Proprietary RPR” section on page 17-8.
Note A best practice is to configure SONET/SDH circuits in an east-to-west or west-to-east
configuration, from Port 0 (east) to Port 1 (west) or Port 1 (east) to Port 0 (west), around the
SONET/SDH ring.
Step 25 Start or resume a Cisco IOS CLI session for the ML-Series card in Adjacent Node 1.
Step 26 Complete the following Cisco IOS configuration for the ML-Series card in Adjacent Node 1, beginning
in global configuration mode:
Step 27 Start a Cisco IOS CLI session for the ML-Series card in Adjacent Node 2.
Step 28 Complete the following Cisco IOS configuration on the Adjacent Node 2 ML-Series card, beginning in
global configuration mode:
Step 29 Use a test set to verify that Ethernet connectivity exists on the Cisco proprietary RPR.
Step 30 Monitor Ethernet traffic and routing tables for at least one hour after the node deletion.
Stop. You have completed this procedure.
Understanding Cisco Proprietary RPR Link Fault Propagation
Link fault propagation (LFP), also known as link pass-through, decreases convergence times in networks
where routers interconnect through ML-Series card Cisco proprietary RPRs. It quickly relays link fau lts
from a master Gigabit Ethernet link to a remote slave link, either Gigabit Ethernet or Fast Ethernet. LFP
greatly improves the time it takes for a router connected to the slave link to fail over to an alternate path.
Under normal protection schemes, convergence might take as long as forty seconds. Using LFP, the slave
interface reflects the state of the master interface in less than a second. This feature is often used to
enable a link failure at a far-end hub site in order to trigger a link down state at a near-end access site.
Figure 17-13 illustrates LFP.
a. Router(config)# interface pos
interface-number
Enters interface configuration mode for the POS port at one
endpoint of the first newly created circuit.
b. Router(config-if)# no shutdown Enables the port.
a. Router(config)# interface pos
interface-number
Enters interface configuration mode for the POS port at one
endpoint of the second newly created circuit.
b. Router(config-if)# no shutdown Enables the port.