Implementation and Evaluation of In- Band Network Telemetry in P4

Abstract: As computer networks grow more complex as the number of connected devices increases, the monitoring and management of such networks also increases in complexity. Current network monitoring tools such as NetFlow, sFlow, ping, traceroute, and tcpdump prove to be both tedious and offer low accuracy when reporting the network state. With the recent emergence in programmable data plane switches, a new framework was created by the P4 Applications Working Group named In- Band Network Telemetry (INT). INT enables network programmers to obtain fine- grained telemetry information directly from the data plane without involvement from the control plane. This project implements INT in hardware Intel Tofino switches and provides a comparison between the three different INT modes of operations (INTXD, INTMX and INTMD) as defined in the framework specifications. The results show the effects of INT when implemented in the data plane, providing the ability to monitor the path a packet took through the network (switch ingress and egress ports), the hop latency, queue occupancy and queuing latency. However, INT can increase the overhead in both the packet and the bandwidth of the network, reducing application throughput. Measures to counteract this are discussed. An earlier implementation of a standalone telemetry report monitoring system was used and analysed, and it allowed for telemetry reports to be reported and visualised at a rate of up to 50 Kpps without any event detection. The results are applied to a Saab 9LV CMS network, and it is concluded that INT allows network operators to obtain a precise overview of the network state, allowing for easier network troubleshooting.