SRv6 Network Debugging Support System Assigning Identifiers to SRH

Segment Routing over IPv6 (SRv6) is used to control mobile communication backbones and data center networks. SRv6 enables flexible control of packets using a list of segments. Network debugging is important to improve network reliability. In network debugging, it is sometimes necessary to track packets in order to identify where packets are dropped. However, conventional tools such as traceroute and ping have difficulty debugging SRv6 networks. In traceroute and ping, probe packets are sent, and ICMP messages in response are used to check the reachability of the packets. In SRv6, which enables flexible operation, the ICMP messages in response are not always returned. In addition, when load balancing such as Equal Cost MultiPath (ECMP) is used, it is not easy to track packets because the routes change dynamically. Therefore, we have developed a network debugging support system that can track packets by assigning identifiers to SRv6 packets. In our system, packet identifiers are assigned as Segment Routing Header (SRH) options. We use Extended Berkeley Packet Filter (eBPF) for identifier assignment to reduce the overhead. After tracking packets by their identifiers, our system verifies the packet routes and visualizes them on a GUI. Our system facilitates understanding of SRv6 network operation and reduces the burden of packet tracking.