Strange terminology : "collision domain"

[Kevin Dorrell]

I have been using the term "collision domain" for years, but it is only when I try explaining it to someone else that I realise I have a problem with it.

I know "collision domain" typically as an Ethernet segment or a collection of Ethernet segments separated by repeaters.

But what about a full-duplex connection between a switch and a host? Is that still a collision domain? Even if there is no concept of collisions in half-duplex?

Does anyone else find this terminology strange?

Kevin Dorrell

Luxembourg

[pflunkert]

Hi Kevin, from the technical view is the term collision domain very easy. A collision domain is the area of a network, in which only ONE station can sent information to the segment or cable. A Switch would seperate this segment. Please remember that a collision domain is not the same as a broadcast domain.

Regards

Peter

[Kevin Dorrell]

Hi Peter,

By this definition is a full-duplex connection between a switch and a host a "collision domain"? Bear in mind that there is no such thing as a collision in full-duplex. Why "collision domain"? Doesn't that make "collision domain" rather a bad terminology?

"Collision domain" came from the time of hubs and half-duplex, where only one station could transmit at a time, and if two stations transmitted it was a "collision". This doesn't really apply in full-duplex switching environments.

My intention was to try and start a debate about words. Isn't it time we abandoned this confusing terminology and went back to calling it an Ethernet segment?

Kevin Dorrell

Luxembourg

[pflunkert]

My answer was the technical definition. On a full-duplex connection you can't have any collsion, so a collision domain don't exists. Collsion domain is a terminolgy from normal ethernet networks. Today you have very rarely collions on you network.

I'am thinking that we can't debate about a collision domain, because the technical description is very precise. We should not misapply this terms.

Regards

Peter

[Kevin Dorrell]

So a full-duplex connection is strictly not a "collision domain". From what you say, the term "collision domain" applies only to half-duplex segments. OK, that makes it clearer, and makes the term acceptable. It seems that it is misapplied very often. Thanks for the clarification.

Kevin Dorrell

Luxembourg.

[Kevin Dorrell]

Sorry, careless typing: second to last paragraph should read "Even if there is no concept of collisions in FULL-duplex?"