This example adapts the basic_tunnel example from the P4 tutorial to run in the ALV topology.
See also: a split variant of this program.
Packets follow a different path in the network when using the tunnel; to emphasise this, we make the path a bit convoluted.
The normal routing follows this path:
p0h3 -> p0e1 -> p0a1 -> c3 -> p3a1 -> p3e1 -> p3h2
In the experiment we'll refer to packets following this path as "Untunneled traffic".
Traffic that use the tunnel, which we'll refer to as "Tunneled traffic", follows this path:
p0h3 -> p0e1 -> p0a0 -> c0 -> p1a0 -> c1 -> p3a0 -> p3e0 -> p3a1 -> p3e1 -> p3h2
Such traffic can be generated by using the --dst_id 1 parameter.
This relies on send.py and myTunnel_header.py which were copied from the basic_tunnel P4 tutorial.
MODE=bt_experiment_base ./tests.sh
MODE=bt_experiment_encapsulated ./tests.sh
We can confirm that the recipient is receiving the tunneled traffic:
~/Documents/Flightplan/P4Boosters/Wharf/splits3/ALV_bt$ tcpdump -nXXSvr test_output/alv_k\=4/pcap_dump/p3e1_to_p3h2.pcap | head
reading from file test_output/alv_k=4/pcap_dump/p3e1_to_p3h2.pcap, link-type EN10MB (Ethernet)
12:02:49.826292 02:00:00:cf:e6:4f > ff:ff:ff:ff:ff:ff, ethertype Unknown (0x1212), length 55:
0x0000: ffff ffff ffff 0200 00cf e64f 1212 0800 ...........O....
0x0010: 0001 4500 0025 0001 0000 4000 f8cf c000 ..E..%....@.....
0x0020: 0103 c003 0102 466c 6967 6874 706c 616e ......Flightplan
0x0030: 2074 6573 7420 31 .test.1
12:02:51.194254 02:00:00:cf:e6:4f > ff:ff:ff:ff:ff:ff, ethertype Unknown (0x1212), length 55:
0x0000: ffff ffff ffff 0200 00cf e64f 1212 0800 ...........O....
0x0010: 0001 4500 0025 0001 0000 4000 f8cf c000 ..E..%....@.....
0x0020: 0103 c003 0102 466c 6967 6874 706c 616e ......Flightplan
0x0030: 2074 6573 7420 32 .test.2
tcpdump: Unable to write output: Broken pipe