= VLAN stitching on the (Tunneling) NetFPGA !OpenFlow Switch = 
This page describes how VLAN stitching can be implemented on a NetFPGA running the Tunneling !OpenFlow bitfile (of1). 
== Topology ==
The NetFPGA bridges two VLANs, 5 and 3733. The connections are as follows:
 * of1:nf2c1 <---- VLAN 5 ---> sw-top:geth0/15
 * of1:nf2c2 <-- VLAN 3733 --> sw-outside:geth0/34
These VLANs were stitched together by pushing flow rules to of1 from `kvm-big`, running the Big Switch controller. 

== Configurations ==
`of1` shows up as DPID 00:00:00:23:20:08:0f:f7 on `kvm-big`. On `of1`, this is the MAC address of interface tap0. [[BR]]

This is done from the CLI, in config-switch mode. 
{{{
kvm-big> en 
kvm-big# conf
kvm-big(config)# switch 00:00:00:23:20:08:0f:f7
kvm-big(config-switch)#
}}}

From the config-switch context, two flow entries are created for `of1`'s DPID on `kvm-big`: one for switching VLAN tags from 3733 to 5 on nf2c2, and the other, from 5 to 3733 on nf2c1.
{{{
  flow-entry port-c1
    active True
    ingress-port 2
    vlan-id 5
    actions set-vlan-id=3733,output=3
  flow-entry port-c2
    active True
    ingress-port 3
    vlan-id 3733
    actions set-vlan-id=5,output=2
}}}  

Setting flow entries from the `config-switch` context is a matter of copy/pasting each line above, and exiting between different flow entries. Key points are:
 * The four ports of the NetFPGA are designated 1,2,3,4, not 0,1,2,3 as the nf2cx numbering might suggest.  
 * 'active True' must be specified to enable the flow policy since the default for any newly created flow is 'active False'
 * at least one layer 2 or lower constraint e.g. ingress/egress port or src/dst MAC must be specified
 * there should be no white-spaces between the actions list. 

=== sanity checks ===
For the sake of sanity checking, IP addresses were assigned to the VLAN interfaces for 5 and 3733 on sw-top and sw-outside, respectively. If successful, pings will work between the two VLAN interfaces.