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Lectures notes for 2010 - KTH

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• the router gets all 100 packets, be<strong>for</strong>e the first has been sent across<br />

the link!<br />

• the new Router Requirements RFC - says that routers should not generate source quench<br />

errors, since it just consumes network bandwidth and it is an ineffective and unfair fix <strong>for</strong><br />

congestion<br />

• In any case, the sending program never responded to the source<br />

quench errors!<br />

• BSD implementations ignore received source quenchs if the protocol is UDP<br />

• the program finished be<strong>for</strong>e the source quench was received!<br />

Thus if you want reliability you have to build it in and do end-to-end flow control,<br />

error checking, and use (and thus wait <strong>for</strong>) acknowledgements.<br />

Maguire Building a UDP packet from scratch 4: 28 of 74<br />

maguire@kth.se <strong>2010</strong>.03.21 Internetworking/Internetteknik

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