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OSPF how handle parallel links

Posted: Thu Jun 17, 2021 11:43 pm
by homerwsmith
Dear gentle Folk,

I have two tiks with 2 identical non bridged links between them

Tik1 port 1 -> AP1 -> SM1-> Tik2 port 1
Tik1 port 2 -> AP2 -> SM2 -> Tik2 port 2
Tik1 port3 GW Tik2 port 3 ->
Port 1 and port 2 are NOT bridged.

What will OSPF do with traffic destined for a subnet on the right?

Will it round robin by default? If so is there any real problem with this?

Wlll i have to use bonding of one kind or another?
Thanks in advance, Homer

Re: OSPF how handle parallel links

Posted: Sat Jun 19, 2021 6:15 pm
by IPANetEngineer
OSPF ECMP will be used if the cost is equal to reach a destination prefix over multiple paths. ECMP is a session based load balancing algorithm - not per packet

From the Tik wiki:

Because results of the forwarding decision are cached, packets with the same source address, destination address, source interface, routing mark and ToS are sent to the same gateway. This means that ECMP route does not perform pure per-connection balancing, but it can be used to load balance connections if at least one of previously mentioned parameters is different than previous connection. See interface bonding if you need to achieve per-packet load balancing. ... .29_routes