[ovs-discuss] ovs dpdk layer 3 port with neighbour protocol stack support

majieyue majieyue at huawei.com
Tue Nov 29 06:16:21 UTC 2016

Hi guys,

When we deploy OVS as NAT node, I am afraid only flow rules is not enough if you don't know the next hop mac address, e.g.

VM ( -> => OVS ( snat to => Server ( ->

In most situations, admin can't know (and should not know) the mac address of, and switches in traditional way always 
learn this info by sending ARP request. But in OVS, I don't know if there is another way except for inserting a flow rule that has mac 
addresses of and and using such actions as mod_dl_src and mod_dl_dst

What I am asking for is adding a layer 3 port, which has some ability similar with current tunnel port, and such layer 3 port can query
route cache which OVS maintained for tunnel, and neigh tables, w/o asking for kernel (especially it runs in DPDK context). Such layer 3 port
is not tunnel port so its behavior only relies on forwarding and modifying l2 headers

I've searched previous mails and there is indeed some work on layer 3 port, but such port doesn't have all I asked above. I am wondering if there 
is a plan on this in future OVS roadmap, What you maintainer guys think about the requirement I proposed.

I am yearning for your advices, and maybe I can contribute to such things if you think it is worth of doing. Correct me if anything wrong, thank you.


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