recirculate_and_add_header

Recirculate and Add Headers

+--+      +--+     ++-+
|h1+------+s1+-----+h2+
+--+      +-++     +--+

Introduction

In this example we show how to recirculate packets and add a headers at each recirculation. At each recirculation it reads the content of a register and adds it to the new header.

To test the program we provide a sending carrier application that sends special packets that indicate how many times do they have to be recirculated.

We also provide a script to automatically fill a register[i]=i values where i in [0,127].

How to run

Start topology:

sudo p4run

or

sudo python network.py

Send Magic packets:

mx h1
python send_carrier.py <num_recirculations>

You can monitor packets at the port 2 of the switch to see that the number of bytes increases as we recirculate more. You can also inspect the value of those packets and verify that they carry the register's content using tcpdump.

sudo tcpdump -i s1-eth2 -Q out