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

Krzysztof Wojciechowski krzysztof.wojciechowski at techstorage.pl
Fri Oct 16 18:52:44 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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