CODEWITHSUNDEEP
network-programmingnetwork-protocolsethernet
Schemer
Schemer

Reputation: 1675

Manchester encoding and collision detection on Ethernet

I'm reading a book about networks and it makes the comment that Ethernet uses Manchester encoding and that, if two hosts are not perfectly in synch with each other, that this allows for early collision detection. It doesn't explain why however and I am wondering if someone can clarify this for me.

Regards.

Upvotes: 2

Views: 1417

Answers (2)

maths-help-seeker
maths-help-seeker

Reputation: 966

The answer for syncing can be found here: http://en.wikipedia.org/wiki/Manchester_code.

The answer for collision detection can be found here. http://www.google.com/patents/US5012467. It is link to an US Patent but its abstract describes why collision detection is possible with manchester encoding.

Upvotes: 0

hookenz
hookenz

Reputation: 38947

Suggest you read the wiki article on CSMACD which is what ethernet uses. It explains how the collision detection algorithm works.

http://en.wikipedia.org/wiki/Carrier_sense_multiple_access_with_collision_detection

This of course is less of an issue now with switched networks but was useful in the "old days" of bus style cable ethernet or hub based broadcast ethernet.

Upvotes: 1

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