Sign in with
Sign up | Sign in
Your question

Do two Transceivers = Collision Domain?

Last response: in Networking
Share
Anonymous
June 7, 2005 5:30:40 PM

Archived from groups: comp.dcom.lans.ethernet (More info?)

To settle an old argument, do two transceivers with a cable between them
(of PHD spec lenght) constitute a valid collision domain? Years ago I was
told that was considered extremely bad practice....
Anonymous
June 7, 2005 6:10:28 PM

Archived from groups: comp.dcom.lans.ethernet (More info?)

"Hal Kuff" <kuff@tessco.com> wrote:
>To settle an old argument, do two transceivers with a cable between them
>(of PHD spec lenght) constitute a valid collision domain?

Sure, why not? If they both talk at the same time, they'll collide.
[Well, unless they are full-duplex, but then there are no collisions,
so talking about a domain for them isn't sensical...]

>Years ago I was
>told that was considered extremely bad practice....

What was? To put two transcievers on a cable? To consider that a
collision domain?

Maybe I'm missing something, what's "PHD spec lenght"?
Anonymous
June 7, 2005 10:47:36 PM

Archived from groups: comp.dcom.lans.ethernet (More info?)

Sorry I meant PHY, that is to say the cable length would satisfy minimum
length .....Honestly, there seemed a debate occuring in past years about
whether the spec supported the use of transceivers in this manner.


<William P. N. Smith> wrote in message
news:qioba1hrgifodd1j5budr7e40049spi1b5@4ax.com...
> "Hal Kuff" <kuff@tessco.com> wrote:
>>To settle an old argument, do two transceivers with a cable between them
>>(of PHD spec lenght) constitute a valid collision domain?
>
> Sure, why not? If they both talk at the same time, they'll collide.
> [Well, unless they are full-duplex, but then there are no collisions,
> so talking about a domain for them isn't sensical...]
>
>>Years ago I was
>>told that was considered extremely bad practice....
>
> What was? To put two transcievers on a cable? To consider that a
> collision domain?
>
> Maybe I'm missing something, what's "PHD spec lenght"?
>
Related resources
Anonymous
June 8, 2005 5:16:33 PM

Archived from groups: comp.dcom.lans.ethernet (More info?)

In article <11ac90c34kvc7ea@corp.supernews.com>,
"Hal Kuff" <kuff@tessco.com> wrote:

> Sorry I meant PHY, that is to say the cable length would satisfy minimum
> length .....Honestly, there seemed a debate occuring in past years about
> whether the spec supported the use of transceivers in this manner.
>

In the case of 10/100/1000BASE-T, having only two transceivers connected
by a proper cable is the ONLY way to connect them. Unlike
10BASE2/10BASE5 (coaxial Ethernet), you cannot have more than two
transceivers connected to a given cable.

Whether those two transceivers comprise the entire collision domain or
only a portion of it is a function of the hub device (bridge/switch vs.
repeater). Remember, the hub device has an internal transceiver for each
port, and all 10/100/1000BASE-T configurations use only point-to-point
links between pairs of transceivers.


--
Rich Seifert Networks and Communications Consulting
21885 Bear Creek Way
(408) 395-5700 Los Gatos, CA 95033
(408) 228-0803 FAX

Send replies to: usenet at richseifert dot com
Anonymous
June 9, 2005 1:20:31 AM

Archived from groups: comp.dcom.lans.ethernet (More info?)

On Tue, 7 Jun 2005, Hal Kuff wrote:

> To settle an old argument, do two transceivers with a cable
> between them (of PHD spec lenght) constitute a valid collision
> domain?

Any chance of a translation into English for native speakers?

Back in co-ax days, there was a recommended minimum distance between
nodes for proper collision resolution, if that has any relevance to
the question.
!