R0106-HP MSR Router Series Layer 3 - IP Routing Configuration Guide(V7)

Ste

Command

Remarks

2. Configure the source address of echo

packets.

bfd echo-source-ip ip-address

By default, the source address

of echo packets is not

configured.

3. Enter interface view.

interface interface-type

interface-number

N/A

4. Enable BFD single-hop echo detection.

ospf bfd enable echo

By default, BFD single-hop

echo detection is disabled.

Configuring OSPF FRR

A link or router failure on a path can cause packet loss and even routing loop until OSPF completes

routing convergence based on the new network topology. FRR enables fast rerouting to minimize the

impact of link or node failures.

Figure 21 Network diagram for OSPF FRR

In Figure 21, configure FRR on Router B by using a routing policy to specify a backup next hop. When the

primary link fails, OSPF directs packets to the backup next hop. At the same time, OSPF calculates the

shortest path based on the new network topology. It forwards packets over the path after network

convergence.

You can configure OSPF FRR to calculate a backup next hop by using the loop free alternate (LFA)

algorithm, or specify a backup next hop by using a routing policy.

Configuration prerequisites

Before you configure OSPF FRR, complete the following tasks:

• Configure IP addresses for interfaces to ensure IP connectivity between neighboring nodes.

• Enable OSPF.

Configuration guidelines

• Do not use FRR and BFD at the same time. Otherwise, FRR might fail to take effect.

• Do not use the fast-reroute lfa command together with the vlink-peer or sham-link (see MPLS

Command Reference) command.

• When both OSPF PIC and OSPF FRR are configured, OSPF FRR takes effect.