• McKeown Group OpenFlow WiFi Network (aka "ofwifi")
Skip to end of metadata
Go to start of metadata

Network Topology (logical, datapath)

Tunneling

OpenFlow APs are scattered in the building and we don't always have direct physical connection from our OpenFlow switch to them. This configuration creates multiple OpenFlow islands, which most of the current OpenFlow controllers ('controller applications' to be exact) do not support. We use L2 over IP tunneling software (capsulator) to deal with this situation.

The figure below illustrates how tunneling works in OpenFlow WiFi network. The right column shows the switch adjacency we would like to have and the left column shows the physical topology we deployed. The challenge here is we have many (~30) APs that use tunneling and we need to feed their traffic into the different physical port of our OpenFlow switch. Noiive way to do this is to have 30 of PCs on which run tunneling software. Another naiive way is to have a single PC which have 30 of ethernet interfaces. Both are not practical. Insted we used a single PC with two ethernet interfaces and a VLAN tag switch. The PC running tunneling software feeds the traffic from an AP (say AP number X) to the VLAN tag switch with vlan tag X. The VLAN tag swtich is configured in such a way that it has as many vlans as APs and each vlan has two ports -- a non-tag port and vlan tagged port where all the vlans share a single tagged port which is connected to the tunneling termination PC. That way, the packet from PC with different vlan tag is forwarded to the different non-tag ports.

One caveat is that the VLAN swtich (Quanta in the figure) drops some L2 control packet including 802.1 standard LLDP packet (destination MAC address starts with 01:80:C2), which many OpenFlow controllers use to discover the network topology. Using non-standard LLDP destination can avoid this issue. 

Switch DIPDs


Switch Name

DPID

IP address

Location

Note

necsw4

00:00:00:12:e2:98:a5:df

172.24.74.97

Comm3.3

 

wimax-bs

00:00:d8:d3:85:00:00:00

171.64.94.175

Packard

 

necsw5

01:76:00:12:e2:78:32:44

172.24.74.193

Comm3.3

 

hpsw3

01:76:00:25:61:64:8f:00

172.24.70.211

Comm3.2

 

swan-ap2

00:00:00:0d:b9:00:00:02

172.27.74.201

Basement

 

swan-ap3

00:00:00:0d:b9:00:00:03

172.27.74.202

1F

Tunnel

swan-ap4

00:00:00:0d:b9:00:00:04

172.27.74.203

1F

Tunnel

swan-ap5

00:00:00:0d:b9:00:00:05

172.27.74.204

1F

Tunnel

swan-ap6

00:00:00:0d:b9:00:00:06

172.27.74.205

1F(G104)

Tunnel

swan-ap7

00:00:00:0d:b9:00:00:07

172.27.74.206

1F

Tunnel

swan-ap8

00:00:00:0d:b9:00:00:08

172.27.74.207

1F

Tunnel

swan-ap9

00:00:00:0d:b9:00:00:09

172.27.74.208

2F

Tunnel

swan-ap10

00:00:00:0d:b9:00:00:0a

172.27.74.209

2F

Tunnel

swan-ap11

00:00:00:0d:b9:00:00:0b

172.27.74.210

2F

Tunnel

swan-ap12

00:00:00:0d:b9:00:00:0c

172.27.74.211

2F

Tunnel

swan-ap13

00:00:00:0d:b9:00:00:0d

172.27.74.212

2F

Tunnel

swan-ap14

00:00:00:0d:b9:00:00:0e

172.27.74.213

2F

Tunnel

swan-ap15

00:00:00:0d:b9:00:00:0f

172.24.74.51

3F

Direct

swan-ap16

00:00:00:0d:b9:00:00:10

172.24.74.59

3F

Direct

swan-ap17

00:00:00:0d:b9:00:00:11

172.24.74.85

3F

Direct

swan-ap18

00:00:00:0d:b9:00:00:12

172.24.74.84

3F

Direct

swan-ap19

00:00:00:0d:b9:00:00:13

172.27.74.218

3F

Tunnel

swan-ap21

00:00:00:0d:b9:00:00:15

172.27.74.220

3F

Tunnel

swan-ap22

00:00:00:0d:b9:00:00:16

172.27.74.221

3F

Tunnel

swan-ap23

00:00:00:0d:b9:00:00:17

172.27.74.222

4F

Tunnel

swan-ap24

00:00:00:0d:b9:00:00:18

172.27.74.223

4F

Tunnel

swan-ap25

00:00:00:0d:b9:00:00:19

172.27.74.224

4F

Tunnel

swan-ap26

00:00:00:0d:b9:00:00:1a

172.27.74.225

4F

Tunnel

swan-ap27

00:00:00:0d:b9:00:00:1b

172.27.74.226

4F

Tunnel

swan-ap28

00:00:00:0d:b9:00:00:1c

172.27.74.227

4F

Tunnel

swan-ap29

00:00:00:0d:b9:00:00:1d

172.27.74.228

5F

Tunnel

swan-ap30

00:00:00:0d:b9:00:00:1e

172.27.74.229

5F

Tunnel


For WiFi APs, visit Gates Network OpenFlow WiFi AP Info (restricted access)

  • No labels