| 摘要 |
A traceroute mechanism enables responses to the traceroute to reach the originating router (originator) along a multihop pseudowire (PW). A traceroute message includes an accumulator operable to count hops along a MH-PW, implemented as a time-to-live (TTL) field, as is known in the art. An originator router employs multiple TTL values, and decrements one of the TTL "accumulators" for each hop. At the ultimate (terminal) router defining the end of the multihop PW, a TTL in the return message is set to the number of hops traveled by the traceroute. The difference between the accumulator and the initial TTL value determines the number of hops traveled by the traceroute message, and hence the number of hops back to the originating node. The traceroute return message, now having a TTL set to the number of hops of the counterpart traceroute, reaches the originator when the TTL value is decremented to zero.
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