[ovs-dev] Hybrid VLAN capability

[Jean Tourrilhes]

Ken Ajiro wrote :
> 
>   To isolate the L2 domain equivalent to VLAN,
>   I think that following flow entries will be needed.
> 
> in_port=1,vlan_id=100,actions=output:2,output:7,output:8
> in_port=1,vlan_id=110,actions=output:2,output:7,output:8
> in_port=1,vlan_id=120,actions=output:2,output:7,output:8
> in_port=1,drop
> in_port=2,vlan_id=100,...

	The way to avoid cross product explosion has always been to
use multiple tables.
	Actually, Egress Tables introduced in 1.5 were explicitely
designed to address this use case in a generic fashion, because Egress
Tables have exactly the semantic you want. Instead of adding a table
in the output port restricted/dedicated to only VLAN and nothing else,
it introduce a generic OpenFlow table after the output action, so that
not only you can do VLAN filtering, but you can also implement STP
filtering, Reverse Path Filtering or any per-output port policies. In
other words, it is future proof.
	In other words, please look at implementing Egress Tables in
OVS instead of Hybrid Port VLAN. IMHO, I think Ben would be more
likely to merge it. I think the current trend of trying to push more
and more specialised/dedicated features in OVS is not sustainable.
	Regards,

	Jean