[ovs-discuss] Openvswitch with DPDK - gre tunnels over dummy interface

Krzysztof Wojciechowski krzysztof.wojciechowski at techstorage.pl
Tue Oct 20 17:04:30 UTC 2015


Hello

I have few questions about improving performance of our openvswitch
implementation. Now we are using some old openvswitch (1.8 or something
like that) on few machines. We are going to update them. We are using
them for routers for our software defined network.

Details:
1.Machines have few ovs bridges.
2.Every bridge have one local interface (with assigned ip) and a lot of
gre tunnels.
3.Machines use ospf to communicate with our internal network (to other
machines - gre tunnels, its not reachable from inside of ovs networks).
4.They have dummy interface with IP (other machines in network use this
ip for gre tunnels)
5. This machines have other interface to communicate with internet.
6. we have own modified openflow controller
Its something like this:
http://blog.scottlowe.org/2012/10/31/layer-3-routing-with-open-vswitch/
But we use gre tunnels instead of vlans and separate ovs bridges.

first question- is DPDK fit here? if other nodes are communicating with
ip on dummy interface its going trough linux routing and then to
openvswitch or directly from interface to ovs?

Second question - I watched this video:
https://www.youtube.com/watch?v=MbBX_J5zR4w
DPDK performance drop a lot when number of flows increase - was it
fixed? or can i expect low performance when i will have ~250 flows per
bridge?

third question  - i have idea to implement routing in openvswitch - is
there a way to "forward" packets between ovs bridges (i would modify it
using flows)? or i have to connect everything to one bridge (i would
like to avoid it because of modified controller - don't know what will
happen)? or i can use another bridge over interfaces connected to local
interfaces or something?

last question - i saw that "ovs-ofctl" commands have problems with
multiple flow tables (in 2.3 and older openvswitches) - for examples
ovs-ofctl replace-flows. Is it fixed in 2.4? Or someone can fix that?

Sorry for my bad english.

Regards
Krzysztof






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