wiki:Internal/OpenFlow/VLANstitching

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.

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

If using the REST API, the exact same keyword=value pairs can be placed in a HTTP PUT using a script, or a tool such as curl:

% curl -d '{"switch": "00:00:00:23:20:08:0f:f7", "name": "port-c1", "active": "true" ... }'  http://<controller_ip>:8080/wm/staticflowentrypusher/json

Setting flow entries from the config-switch context is a matter of copy/pasting each line above, and exiting contexts 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

The NetFPGA host implements OpenFlow features via the following processes:

root      1374     1  0 10:55 ?        00:00:00 /opt/netfpga2.1.1/openflow/udatapath/ofdatapath -D punix:/var/run/test -d 002320080ff7 -i nf2c0 nf2c1 nf2c2 nf2c3
root      1452     1  0 10:55 ?        00:00:00 /opt/netfpga2.1.1/openflow/secchan/ofprotocol -D unix:/var/run/test tcp:nox.orbit-lab.org:6633 --out-of-band

To check for flows on the host itself, dpctl should be used. The commands to pull the switch's status and current flows (e.g. traces) are:

dpctl show unix:/var/run/test
dpctl status unix:/var/run/test
dpctl montior unix:/var/run/test

This is similar to the commands show [DPID] status and show [DPID] trace detail on the controller CLI.

An external test involved IP address assignments to the VLAN interfaces for VLANs 5 and 3733 on sw-top and sw-outside, respectively. The IP addresses were pinged from each side; Pings pass between the two VLAN interfaces when stitched correctly.

Last modified 7 years ago Last modified on 05/16/12 01:55:21