Configuring OSPFv3 IP FRR
If a link fails, an OSPFv3 IP FRR-capable device can fast switch traffic to a backup link, which protects traffic and improves OSPFv3 network reliability.
Usage Scenario
As networks develop, services such as Voice over IP (VoIP) and on-line video services require high-quality real-time transmission. Nevertheless, if an OSPFv3 fault occurs, traffic can be switched to a new link only after the fault detection that lasts milliseconds, fault notification to the routing control plane that lasts milliseconds, new topology information generation and flooding that lasts milliseconds, Shortest Path First (SPF) calculation that lasts tens of milliseconds, and new route notification and adding that lasts hundreds of milliseconds. As a result, it takes much more than 50 ms, the maximum convergence time tolerable for VoIP and on-line video services, which cannot meet the requirement for real-time services on the network.
With OSPFv3 IP FRR that calculates a backup link in advance, devices can fast switch traffic to the backup link without interrupting traffic if the primary link fails, which protects traffic and improves OSPFv3 network reliability.
OSPFv3 IP FRR is applicable to services that are sensitive to the packet delay and packet loss.
After OSPFv3 IP FRR is configured, the lower layer needs to fast respond to a link change so that traffic can be fast switched to the backup link. After FRR and BFD are bound, link failures can be detected rapidly so that traffic is rapidly switched to the backup link if the primary link fails.
- Enabling OSPFv3 IP FRR
With OSPFv3 IP FRR and loop-free backup links, a device can switch traffic to a backup link immediately if the primary link fails. - (Optional) Binding IP FRR and BFD
Binding IP FRR and BFD enables the lower layer to fast respond to a link change so that traffic can be rapidly switched to the backup link if the primary link fails. - (Optional) Blocking FRR on an OSPFv3 Interface
If FRR is not required on certain OSPFv3 interfaces, FRR needs to be blocked on these interfaces. - Verifying the Configuration of OSPFv3 IP FRR
After configuring OSPFv3 IP FRR, you can view information about the primary and backup links.
Enabling OSPFv3 IP FRR
With OSPFv3 IP FRR and loop-free backup links, a device can switch traffic to a backup link immediately if the primary link fails.
Procedure
- Run system-view
The system view is displayed.
- Run ospfv3 [ process-id ] [ vpn-instance vpn-instance-name ]
An OSPFv3 process is enabled, and the OSPFv3 view is displayed.
- Run frr
The OSPFv3 IP FRR view is displayed.
- Run loop-free-alternate
OSPFv3 IP FRR is enabled, and a loop-free backup link is generated.
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NOTE: OSPFv3 can generate a loop-free backup link only when the OSPFv3 IP FRR traffic protection inequality is met.
- (Optional) Run frr-policy route { route-policy route-policy-name | route-filter route-filter-name }
An OSPFv3 IP FRR filtering policy is configured.
After the OSPFv3 IP FRR filtering policy is configured, only the OSPFv3 backup routes that match the filtering conditions of the policy can be added to the forwarding table.
- (Optional) Run tiebreaker { node-protecting | lowest-cost } preference preference
The solution of selecting a backup path for OSPFv3 IP FRR is set.
By default, the solution of selecting a backup path for OSPFv3 IP FRR is node-protection path first. In some cases, the solution needs to be changed to smallest-cost path first because of data forwarding capacity or link cost consideration. In Figure 6-5, the primary path is Link-1 (Device S -> Device E -> Device D), and Link-2 and Link-3 (Device S -> Device N -> Device D) are backup path candidates. By default, Link-3 is selected as the backup path. To change the solution of selecting a backup path for OSPFv3 IP FRR to smallest-cost path first, run the tiebreaker command. After the command is run, Link-2 is selected as the backup path. - Run commit
The configuration is committed.
(Optional) Binding IP FRR and BFD
Binding IP FRR and BFD enables the lower layer to fast respond to a link change so that traffic can be rapidly switched to the backup link if the primary link fails.
Context
Binding the BFD session status to the link status of an interface ensures that link failures are detected rapidly and that traffic is rapidly switched to the backup link.
- If IP FRR of an OSPFv3 process is bound to BFD, IP FRR on all interfaces in the OSPFv3 process is bound to BFD.
- If only a small number of interfaces need to have IP FRR bound to BFD, bind IP FRR on each interface to BFD one by one.
Perform the following steps on the NE where IP FRR and BFD need to be associated:
(Optional) Blocking FRR on an OSPFv3 Interface
If FRR is not required on certain OSPFv3 interfaces, FRR needs to be blocked on these interfaces.
Verifying the Configuration of OSPFv3 IP FRR
After configuring OSPFv3 IP FRR, you can view information about the primary and backup links.
Procedure
- Run the display ospfv3 [ process-id ] routing verbose command to view the primary and backup links after OSPFv3 IP FRR is enabled.
Example
Run the display ospfv3 [ process-id ] routing command on the device running OSPFv3 to view information about the backup next hop.
<HUAWEI> display ospfv3 routing verbose OSPFv3 Process (1) Destination :34:: Prefix Length :64 Metric :1 Type :INTRA-AREA Nexthop ::: Nexthop Interface:Eth0/3/0 Priority :Low Destination :44:: Prefix Length :64 Metric :2 Type :INTRA-AREA Nexthop :FE80:ABCD:ABCD:ABCD::ABCD Nexthop Interface:Eth0/3/0 Backup Nexthop:FE80::2200:10FF:FE03:0 Backup Interface :Eth0/3/0.1 Backup Type :LINK PROTECT Priority :Low
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