Talk:Head-of-line blocking

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[edit] TODO

A diagram may assist the understanding further.

[edit] Effect on switch throughput

Where did this statistic come from? (Karmastan 22:23, 17 February 2007 (UTC))

[edit] A factual error

"HOL arises when packets arriving at the same input port are destined for different output ports."

This does not make sense. I think it should be: "HOL arises when packets arriving at different input ports are destined for the same output port." Otherwise no contention can obviously occur at the output. I am going to fix it. Uploading also an illustration I made.

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HOL blocking can be both ways. If a 100TX input is linked to a 10TX output, then additional packets can be blocked. Also, if multiple inputs are converging on one output as you mentioned.

13:43, 15 October 2007 (UTC)~

I think the article needs to mention a different definition of HOL blocking in the context of TCP. If packet N gets dropped, when N+1, N+2, N+3, ... is received, instead of ACK'ing with N+1, N+2, etc., it ACK's with N-1. This creates an inherent problem in TCP that allows only one hole to be filled each round trip time.

Robertbrichter 13:43, 15 October 2007 (UTC) Robert Richter