[strongSwan] Multiple tunnels between same peer

[Martin Willi]

> But I would like to know what these values mean (10, 11, 20, 21) and
> how they help in sending traffic through a particular tunnel only. I
> need to try and set up multiple tunnels, and then send traffic through
> each one of them, and then all of them together, in order to compare
> performances. 

You can use the same mark values in iptables to tag traffic for use with
a specific tunnel, have a look at [1]. 

Use the MARK target to set a mark on a packet. Depending on the mark you
set, the tunnel with the mark configured in ipsec.conf will be used.

Regards
Martin

[1]http://www.strongswan.org/uml/testresults/ikev2/rw-mark-in-out/console.log