[cisco-voip] 24 port switch question

[Matthew Ballard]

Agreed.  I think it is a badly worded question.  A follow up email from the
original poster indicated it was a multiple choice question.  The keyword
appears to be simultaneously, and collisions are really a non-factor.  If
you¹re looking at an exact snapshot of the shortest time possible, you can¹t
forward more than one frame per port (possibly 2 if you include duplex, one
in each direction), but 24 was one of the answers,  and 48 was not.

Matthew



On 9/29/10 8:33 PM, "Norton, Mike" <mikenorton at pwsd76.ab.ca> wrote:

> If you completely fill the MAC table of a switch, you¹ll ³turn it into a hub²
> in the sense that it would start forwarding traffic out all ports. But you
> still wouldn¹t have collisions, because the ports would still all be full
> duplex.
 
If all ports are full duplex, there is no amount of traffic that could cause
collisions. Collisions can only occur on shared media and shared media can
only be half duplex. With enough traffic, you¹ll start getting
dropped/delayed frames - but that¹s not a collision.
 
At least, that¹s my take on it.
 
-- 
Mike Norton
I.T. Support
Peace Wapiti School Division No. 76
Helpdesk: 780-831-3080
Direct: 780-831-3076
 

From: cisco-voip-bounces at puck.nether.net
[mailto:cisco-voip-bounces at puck.nether.net] On Behalf Of Lelio Fulgenzi
Sent: September-29-10 6:07 PM
To: Matthew Ballard
Cc: cisco-voip at puck. net
Subject: Re: [cisco-voip] 24 port switch question
 

I recall a bug/exposure where one could turn a switch into a hub by flooding
the switch with arp announcements or something like that.

Š

Don't look at me, my iPod maid that spilling mistake.


On 2010-09-29, at 5:57 PM, Matthew Ballard <mballard at otis.edu> wrote:
> 
> On a switch with all ports running full duplex, the collision domain is
> reduced down to the level of the individual port (which is one of the key
> benefits of a switch), so you should never see a collision if all ports are
> connected at full duplex to other switches and/or devices.
> 
> Beyond that, it depends on the switch, as you¹ll hit either port capacity or
> forwarding limits of the switch before anything gets dropped.
> 
> Matthew Ballard
> Network Manager
> Otis College of Art and Design
> mballard at otis.edu
> 
> 
> On 9/29/10 1:41 PM, "Robert Shearrill" <rshearri at uchicago.edu> wrote:
> Hi, 
> 
> Can some answer this question for me, or tell me where i can find the reading
> on this question? I have looked and can find it no where.
> 
> Question:
> 
> How many frames can pass through a 24-port switch simultaneouly, without
> causing a collision and with using full duplex used on all ports?
> 
> Thanks
> 
> Robert 
> 
> 
> _______________________________________________
> cisco-voip mailing list
> cisco-voip at puck.nether.net
> https://puck.nether.net/mailman/listinfo/cisco-voip
> 
> _______________________________________________
> cisco-voip mailing list
> cisco-voip at puck.nether.net
> https://puck.nether.net/mailman/listinfo/cisco-voip
> 
> 
> _______________________________________________
> cisco-voip mailing list
> cisco-voip at puck.nether.net
> https://puck.nether.net/mailman/listinfo/cisco-voip
>> 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://puck.nether.net/pipermail/cisco-voip/attachments/20100929/802cfa12/attachment.html>