A Little Confused over Cross over and Straight Through Cabling

owen2433

owen2433

owen2433

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Right, Doing some uni work and researched google for a while and haven't Gotten up to a Reasonable Answer as of yet.

Right, i know there are standards such as T568A and B for cabling. Cross over cabling is to connect two computers together and Straight through is to connect Computers to Router ETC . . correct of wrong?

Some sites say different some are confusing, but i know the absis of Cross over connects PC - PC or any other X - X , C - C.

But lets take at my home. I have a Netgear DG834. 3 Computers connected through the Network cable. Is my cable be Cross over or Straight Through. Im a bit confused on when would you use Cross over elsewere and Straight through

Mike :)
 
Modern switches and routers allow you to use x-over or straight through, however, for computer<->x-over is required.

In the days of hubs, you needed straight through iirc.
 
think of devices that run at layer 2 and layer 3

layer 2 - hubs, switches etc
layer 3 - ethernet cards, routers etc

same to same - cropss cable
different layers - straight
 
jimjamuk said:
think of devices that run at layer 2 and layer 3

layer 2 - hubs, switches etc
layer 3 - ethernet cards, routers etc

same to same - cropss cable
different layers - straight
Click to expand...

really??

so the hub that i've got plugged into a switch doesn't work then???
 
on that eth card to a router - remember home routers have switch ports built in these days - you would need a cross cable to plug an eth card into a proper router port which you normally have plugged into your uplink to your ISP

As for that hub to switch - has it got auto MDI? or is it multilayered?
 
Correct me if I am wrong, but a switch is not defined as being such because it allows you to use a straight-through to perform connectivity from, say, an eth interface. Its a switch because its actually intelligent and is not broadcasting the packets all over the place.

Since when were crossovers used for anything but ad-hoc connectivity between two eth interfaces or uplinking where the device did not have auto-uplinking capability?

you would need a cross cable to plug an eth card into a proper router port which you normally have plugged into your uplink to your ISP
Click to expand...

Eh..? Define 'Proper Router port'.
 
Sin_Chase said:
Since when were crossovers used for anything but ad-hoc connectivity between two eth interfaces or uplinking where the device did not have auto-uplinking capability?
Click to expand...

Definitely with the older cisco routers (eg the 2500 series) You had to use a xover cable for router to router, or router to PC.

I recently needed to use a crossover for a 2600 router to a Pix firewall (for example)
 
sorry guys - there are so many devices out there now which will either autosense or be intelligent switches which can make it all sound confusing because its not as straightforward as it used to be

Modern home routers have two types of ports - switch ports (normally around 4 of them on the back) and the uplink port (which will be a routed port). The switch ports are all layer 2 so straight cables to eth cards which put all the interfaces in a broadcast domain. The uplink port thoug is different and you wouldnt be able to get an eth card connected with a straight cable - its a routed (layer 3) port and would need a cross cable. Just like in oddjobs62's example - the router and pix are layer 3 devices hence the cross cable

In the ISP world its stil pretty straightforwards - routers route and switches switch (bar the new multilayered switches!) which makes it easy to figure out which cables are needed.
 
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