>It's kind of funny that nobody thinks about this. A network of hubs must be
>designed in a hierarchical fashion. I guess that is just second-nature to
>people who grew up with hubs.
I thought about it too (and was shaking my head to the uh-uh fashion), but
was waiting for your reply... :)
(The thought that ran through my head was :
Ooooo, Priscilla's gonna love this one, hehehe...
Have a good one!
-Mark
-----Original Message-----
From: Priscilla Oppenheimer [mailto:[EMAIL PROTECTED]]
Sent: Mon 12/9/2002 12:10 PM
To: [EMAIL PROTECTED]
Cc:
Subject: RE: Dumb question [7:58783]
Jay Dunn wrote:
>
> A "hub" or "repeater" operates at layer 1 and makes no
> intelligent
> decision about what to forward. A packet enters a port and is
> forwarded
> out all other active ports on the hub. The concept of a loop
> only exists
> at higher layers.
A loop could exist at the physical layer too. A newbie could connect the
hubs in such a way that there was a loop. And it could indeed cause problems
due to the fact that a hub doesn't make any intelligent decisions about what
it forwards, as you say, and doesn't participate in higher-layer
loop-avoidance solutions such as STP, Dijkstra, split horizon, etc. There
would be nothing to stop the looping bits. The very idea makes me cringe.
:-)
It's kind of funny that nobody thinks about this. A network of hubs must be
designed in a hierarchical fashion. I guess that is just second-nature to
people who grew up with hubs.
When hubs entered the market they allowed us to move away from the
ubiquitous bus topology and into a star (hub-and-spoke) topology. They
allowed us to start using the structured cabling that AT&T and other vendors
were starting to install, rather than the Christmas-tree-lights topology so
popular with coax cable and so prone to problems. As networks grew, it
became necessary to connect multiple hubs. The term that was often used was
"cascating hubs." Hubs cascaed from other hubs, within the rules related to
Ethernet propagation delay and collision detection.
Priscilla
>
> Jay Dunn
> IPI*GrammTech, Ltd.
> www.ipi-gt.com
> Nunquam Facilis Est
>
> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On
> Behalf Of
> Han Chuan Alex Ang
> Sent: Monday, December 09, 2002 3:44 AM
> To: [EMAIL PROTECTED]
> Subject: Dumb question [7:58783]
>
> I am wondering if Hub could be subjected to loop problems , if
> not, what
> will happen if there is a loop within a Hub enviroment
Message Posted at:
http://www.groupstudy.com/form/read.php?f=7&i=58817&t=58783
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