INT-BMv2

In-Band Network Telemetry for BMv2 P4 switch

Getting started

1. Install dependences:

   • Mininet
   • BMv2
   • p4c
   • Other packages not installed by default: ethtool, xterm

2. Compile code:

   p4c --target bmv2-v1model --std p4-16 switch.p4

   This will produce switch.json file needed for BMv2.

3. Setting up test network:

   sudo python run/demo_net.py --json switch.json

   In other terminal set up rules forwarding rules:

   run/run_forwarding.sh

   And set up rules for In-Band Network Telemetry:

   run/run_int.sh

   Now you can use the standard mininet CLI in the first terminal.

Remarks

• INT metadata is placed behind IP header. So, metrics are collected also for ICMP packets.
• IP packets with metadata are not valid, because field totalLen in IP header is not updated when adding metadata.
• Probably there is a bug in BMv2. Use of field with type varbit in metadata when cloning packet cause that only one packet is forwarded. Others are dropped. As a workaround that, valid metrics are only from last switch and the rest are junk data derived from upper layers headers and data.