Subject: NACK comment...

From: Jon Crowcroft <[email-masked]>
Date: Mon, 31 Jul 2000 18:50:42 +0100

In message <v0421010db5a4d716efc4@[132.250.92.151]>, Brian Adamson typed:

comment on NACK protocols and advance with Time windows (e.g. PGM)

its sometimes nice if there's not only a NACK (and a NACK confirm) but
also a NACK reject, so that both sender and receiver are synchronised
on their view of the data failure at about the same point in the
stream (i.e. for appllciations that are based on synchronouse
messageing style repliaction - e.g. highly avaialble transaction
servers).....

it also has API issues (you need an error return or exception or
event/message at both sender AND receiver at the right point - like
TCP oob data, only not:-)

cheers
jon

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From: "Dan Leshchiner" <[email-masked]>
Date: Mon, 31 Jul 2000 12:29:18 -0700

in PGM this can be done by sending SPM -- trailing edge sequence number would be
greater than NAK'ed seqno.