Hi,
NO!!!!
For a start the cable is a layer 1 device as are the electrical properties of the
ports so the theory of different layered devices does not hold up.
Secondly a layer 2 device cannot talk directly to a layer 3 in another machine. Layer
2 can only talk to layers 1 & 3 in the device it is in. Then layer 1 passes the data
(electrical pulses) to the layer 1 on the next device. If the layer 2 passes the data
(a frame) to layer 3 then layer 3 decides on where to pass it up the protocol stack
only if the layer 3 sees it as valid.
BASIC COMMS (similar to a normal conversation between 2 people)
A talker speaks to a listener via some medium (air, telephone wire, sign language) a
protocol must be agreed to. Maybe English, Chinese or sign language. If someone
spoke to me in sign language thay may as well speak to me in Chinese as I don't
understand either nor would sign language be appropriate over a phone.
Each talker must have a listener if you have two devices that are the same thier
electrical paths will be the same therefore you need a crossover. Switch to switch
(both layer 2 SO WHAT), Switch to Hub (Layer 2 to Layer 1) both are similar
electrically in there port design (this was deliberate to make connections to PC NIC's
and routers etc simple else would would need a NIC for a Hub and a different one for a
Switch) A switch to a hub requires a crossover.
A router or PC to a switch or hub. The ports are different electrically a straight
cable will work. A router to a PC are similar electrically these need a crossover.
X cross over simply puts the send signal to a receive on similar port types nothing
more flash than that. The secrete is cables are a part of layer 1 and have nothing to
do with the upper layers.
I put a spread on this and the pinouts a couple of weeks ago.
Hope this makes it easier.
Teunis
Hobart, Tasmania
Australia
On Wednesday, January 17, 2001 at 10:55:58 AM, Lowell Sharrah wrote:
> funny,, I said the same thing over two months ago. Good rule to follow.
>
> >>> Sampy Ren <[EMAIL PROTECTED]> 01/17/01 10:34AM >>>
> The rule to follow about cross-over or straight
> cabling confusion is this :
>
> If you are connecting same layer devices, use a
> cross-over cable (as in switch to a switch-layer 2 to
> layer 2 or a router to a router -layer 3 to layer 3).
>
> If you are connecting devices from different layers,
> use a straight cable ( as in connecting a switch to a
> router - layer 2 to layer 3 connectivity).
>
> Hopefully this gives you the concept of the cabling
> schema.
>
> Regards/Sampath.
>
> --- Chuck Larrieu <[EMAIL PROTECTED]> wrote:
> > Didn't we just have this discussion - straight thru
> > or crossover - a couple
> > of weeks ago?
> >
> > -----Original Message-----
> > From: [EMAIL PROTECTED]
> > [mailto:[EMAIL PROTECTED]] On Behalf Of
> > Yonkerbonk
> > Sent: Thursday, December 28, 2000 12:47 AM
> > To: sean; [EMAIL PROTECTED]
> > Subject: Re: crossover or straight cable?
> >
> > A trunk port is simply a port that has traffic from
> > more than one VLAN running over it. It is a function
> > of the software to combine and split the data. That
> > has nothing to do with how the cabling is done.
> > If you have a trunk running from switch to switch,
> > it
> > will be crossover. If you have a trunk running from
> > switch to router, it will be straight through.
> > Normal
> > cabling scheme.
> >
> > --- sean <[EMAIL PROTECTED]> wrote:
> > > Tony,
> > >
> > > Are you saying that, to connect "trunk" ports
> > > between switches, crossover
> > > cable is required?
> > >
> > > I know for "switch" ports that's the case, I am
> > > wondering if it is true for
> > > trunk as well.
> > >
> > > Tks
> > >
> > >
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