[ovs-discuss] Interconnection of subnets using OVS

[Justin Pettit]

> On Sep 25, 2015, at 4:08 AM, Nishanth Devarajan <dev_raj82 at yahoo.com> wrote:
> 
> Hello everyone,
> 			So I have an experimental lab setup of multiple subnets which require to have traffic forwarding between them (only in the forward and backward directions ). 
> i.e:                           Subnet1—> Subnet2 —> Subnet3   or    Subnet1 <— Subnet2 <— Subnet3 . 
> 
> The subnets are NOT connected to some router like typical network topologies. Each subnets consists of 2 hosts and and an OVS switch so that traffic can be forwarded between the subnets.
> 
> i.e       													|
> 														|
> 						Each subnet:					    OVS
> 													    /     \
> 													   /	    \
> 													h1	    h2
> 
> Now,  what is the best way to connect the OVS switches ? I was thinking of GRE tunnels (but I could be wrong), and also does the OVS GRE tunnelling have support for subnets ?  I thank you for your help :)

All of the tunnel formats that OVS supports are L2, so they don't inherently have any understanding of subnets.  In fact, neither does OVS; you'd need to program flows to handle any sort of routing.  GRE is a fine tunnel format, but so is VXLAN, STT, and Geneve.  They all have their pros and cons.  If you want to just do some testing, they'll all be about equivalent.

--Justin