At 11:48 AM 10/18/2007, Jeff W. Boote wrote: ...Emile wrote:Packet duplication differs. The reference of time for waiting a copy is the arrival of a first image of the packet. So it does rely on any remote time.
A lost packet, should never be counted as a duplicate. These metrics should not be looked at in isolation - they are related.
We should be using one waiting time-out for all arrivals of a packet launched at T, T+Th. That's how the ITU-T definition works, and the RFC 2680 definition for loss:
I agree.
Henk
... + If the packet fails to arrive within a reasonable period of time, the one-way packet-loss is taken to be one. Note that the threshold of "reasonable" here is a parameter of the methodology.
{Comment: The definition of reasonable is intentionally vague, and is intended to indicate a value "Th" so large that any value in the closed interval [Th-delta, Th+delta] is an equivalent threshold for loss. Here, delta encompasses all error in clock synchronization along the measured path. If there is a single value after which the packet must be counted as lost, then we reintroduce the need for a degree of clock synchronization similar to that needed for one-way delay. Therefore, if a measure of packet loss parameterized by a specific non-huge "reasonable" time-out value is needed, one can always measure one-way delay and see what percentage of packets from a given stream exceed a given time-out value.}
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