Configuring Health Check - Lenovo RackSwitch G8264 Application Manual

Configuring Health Check

© Copyright Lenovo 2016
You can configure tracking/health check parameters for each of the next hop IP
address you specify in the route map. By default, Address Resolution Protocol
(ARP) resolves the next hop IP address. The ARP re‐try interval is two minutes.
Use the following command to configure health check:
RS G8264(config­route­map)# set ip next­hop verify­availability <next hop IP
address> <priority> [icmp|arp] [interval] [retry] [access­list {<access list
ID>|<access list range>}]
Default values:
Protocol: ARP
Interval: 2 seconds
Retry: 3 times
You must configure a separate statement for verifying health check of each next
hop. A maximum of four health check statements can be included in a route map.
Note: When you configure next hops using set ip next­hop command and
health check using the set ip next­hop verify­availability command
in the same route map, only the health check statements will be considered.
Following is an example of a route map health check statement:
RS G8264(config­route­map)# set ip next­hop verify­availability 12.1.1.1
10 icmp access­list 4
Similarly, if there are inconsistent tracking parameters for a particular next hop IP
address among multiple route maps, the route map with the lowest route map
number is considered.
Note: We strongly recommend that you configure health check if all or multiple
next hops specified in the route map belong to the same Spanning Tree Group
(STG). This is required in case of an STP topology change where all forwarding
database (FDB) entries on all the ports in an STG are cleared. In such a scenario, the
associated ARP entries are purged and the next hop specified in the PBR policy
will not get resolved. When health check is configured, the PBR policy will route
the traffic based on the second next hop that you have specified.
Chapter 27: Policy-Based Routing
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