Ouch, you hurt my head reading that. To me, the easier way to explain it is
that hub/switch ports are crossed, unless specified otherwise (like with a
toggle port, or a straight-through port). Therefore, to go from a crossed
hub/switch port to a crossed hub/switch port, you must add another crossover
to "uncross" one of the two crossed ports. If you want to go from node to
node, you must add the cross with a crossover. What's the cross doing?
Nothing more than flipping the transmit and receive pairs.
--
Jason Roysdon, CCNP+Security/CCDP, MCSE, CNA, Network+, A+
List email: [EMAIL PROTECTED]
Homepage: http://jason.artoo.net/
Cisco resources: http://r2cisco.artoo.net/
""Tony van Ree"" <[EMAIL PROTECTED]> wrote in message
[EMAIL PROTECTED]">news:[EMAIL PROTECTED]...
> 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
> > > >
> > > >
> > > > _________________________________
> > > > FAQ, list archives, and subscription info:
> > > > http://www.groupstudy.com/list/cisco.html
> > > > Report misconduct and Nondisclosure violations to
> > > [EMAIL PROTECTED]
> > >
> > >
> > > __________________________________________________
> > > Do You Yahoo!?
> > > Yahoo! Photos - Share your holiday photos online!
> > > http://photos.yahoo.com/
> > >
> > > _________________________________
> > > FAQ, list archives, and subscription info:
> > > http://www.groupstudy.com/list/cisco.html
> > > Report misconduct and Nondisclosure violations to
> > > [EMAIL PROTECTED]
> > >
> > > _________________________________
> > > FAQ, list archives, and subscription info:
> > > http://www.groupstudy.com/list/cisco.html
> > > Report misconduct and Nondisclosure violations to
> > [EMAIL PROTECTED]
> >
> >
> > __________________________________________________
> > Do You Yahoo!?
> > Get email at your own domain with Yahoo! Mail.
> > http://personal.mail.yahoo.com/
> >
> > _________________________________
> > FAQ, list archives, and subscription info:
http://www.groupstudy.com/list/cisco.html
> > Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
> >
> > _________________________________
> > FAQ, list archives, and subscription info:
http://www.groupstudy.com/list/cisco.html
> > Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
> >
> >
>
>
> --
> www.tasmail.com
>
>
> _________________________________
> FAQ, list archives, and subscription info:
http://www.groupstudy.com/list/cisco.html
> Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
>
_________________________________
FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
