1.6 KiB
P4 v1.1 Simple Router
Description
This program is a version of the now famous simple_router program, written according to the P4 v1.1 specification. In addition to the original simple_router, this version can keep track of the number of IPv4 packets dropped because of an expired TTL. This was added to illustrate some of P4 v1.1 more advanced capabilities. For more information on P4 v1.1, please refer to [p4.org] (http://p4.org/spec/).
Look at the [P4 program] (p4src/simple_router.p4) and observe some of the P4 v1.1 additions:
- strong typing in header type definitions and action declarations
- assignment with
=instead ofmodify_field(extension to the v1.1 spec) - register indexing
- support for the ternary operator (extension to the v1.1 spec)
Running the demo
We provide a small demo to let you test the program. Before trying to run the demo, please make sure that your [env.sh] (../env.sh) file is up-to-date.
To run the demo:
- start the switch in Mininet with
./run_switch.sh - in another terminal, populate the table entries with
./add_entries.sh - you should now be able to ping h2 from h1 by typing
h1 ping h2in the Mininet CLI
Once you have the basic demo running, you can start sending packets with a TTL of 1, activate packet drop tracking in the switch and observe the count go up. To do this:
- activate the tracking with
./register_on_off.sh on - send ICMP packets with a TTL of 1 from the Mininet CLI:
h1 ping h2 -t 1. The packets are now dropped by the switch, so you should not be able to observe a reply
To get the drop count, simply run ./read_register.sh.