Arista Networks, Inc.
Traceroute for Overlays Using Dynamic Filters

Abstract:

The disclosure describes processing packets in connection with a traceroute session in an overlay network that includes detecting traceroute probes using static and dynamic rules and using the time to live (TTL) value in a received traceroute probe to compute an outer TTL value. The TTL value (inner TTL) of the received probe is updated based on the number of underlay routers (hops) comprising the underlay network that are detected during the traceroute session. The received probe with its updated TTL value is encapsulated in an outer frame that includes the computed outer TTL value. The number of hops is updated each time an underlay router sends an ICMP time exceeded message.