source_routing

Source Routing

                 
                   
                   +--+
            +------+s2+------+
            |      +--+      |
+--+      +-++              ++-+       +--+
|h1+------+s1|              |s4+-------+h2|
+--+      +-++              ++-+       +--+
            |                |
            |      +--+      |
            +------+s3+------+
                   +--+

         

Introduction

In this example we will show how source hosts can add some custom headers to instruct switches how to route packets in the network. For that we will use header stacks and remove one header at each hop.

How to run

Run the topology:

sudo p4run

Start the receiver script at h2:

mx h2
python receive.py

Send packets with the source routing header indicating which path the packet has to take. Once you start the script it will ask you which path do you want to take.

You can decide to go to h2 through s2 and s4:

mx h1
python send.py 10.0.4.2
Type space separated switch_ids nums (example: "2 3 2 2 1") or "q" to quit: 2 4

Or you can use s3 instead:

python send.py 10.0.4.2
Type space separated switch_ids nums (example: "2 3 2 2 1") or "q" to quit: 3 4

You can also do some loops:

python send.py 10.0.4.2
Type space separated switch_ids nums (example: "2 3 2 2 1") or "q" to quit: 2 4 3 1 2 4