Ensuring SD-WAN prioritizes healthy SD-WAN members
When using the SD-WAN rule option set tie-break fib-best-match, traffic that matches this rule will be sent through member(s) with the best FIB match for the destination. This can result in traffic taking unhealthy links.
When combined with the setting set minimum-sla-meet-members 1, SD-WAN rules will prioritize members that are in-SLA, and use the FIB to select the best path if there are multiple members within SLA.
Example use cases:
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In multi-hub environments where each hub provides access to a resource, one hub may be preferred over the other. When both hubs are in-SLA, the FIB can be used to prefer one hub over the other. If the preferred hub is not in SLA, the secondary hub (though less preferred) will be used as it is in SLA.
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When using ADVPN, if the shortcut tunnels and the spoke-to-hub tunnels are both in SLA, spoke-to-spoke traffic will prefer ADVPN shortcut tunnels as they will be the best according to the FIB. If the shortcut tunnels are out of SLA, the spoke-to-hub tunnel (though less preferred) will be used as it is in SLA.
config system sdwan
...
config members
edit 1
set interface "port3"
set zone "WAN1"
next
edit 2
set interface "port4"
set zone "WAN2"
next
edit 3
set interface "HUB1-VPN1"
set zone "HUB1"
set cost 10
...
next
edit 4
set interface "HUB1-VPN1-2"
set zone "HUB1"
set cost 11
...
next
edit 5
set interface "HUB2-VPN1"
set zone "HUB2"
set cost 20
...
next
edit 6
set interface "HUB2-VPN1-2"
set zone "HUB2"
set cost 21
...
next
end
...
config service
edit 1
set name "HUB"
set mode sla
set minimum-sla-meet-members 1
set dst "Datacenter"
set src "all"
config sla
edit "HUB"
set id 1
next
end
set priority-members 3 4 5 6
set tie-break fib-best-match
next
end
end