Connecting two Gigabit Switches Together

(snip)

How sure are you that the cable is good? Specifically that it isn't mispaired? Is it a commercial four pair cable, or homemade?

-- glen

Do they have Auto-X, or do you need to use a crossover cable ?

(snip)

Gigabit transmits and receives on all four pairs at the same time. It is most obvious to connect two ports with a straight cable, but they are supposed to also work with a crossover.

-- glen

Bonjour Glen,

And now, reading your reply, I'm wondering how full-duplex is possible. The Ethernet 100Base-T4 (never used) was also on four pairs, and full-duplex was not possible.

For the Ajay question, what is the impact of Master and Slave configuration for 1G?

Best regards, Michelot

Thanks for your response... The cable is home made, it runs beetween two floors.. It was tested with a cat5e cable tester and all pairs are connected in the right sequence.. It' also works fine (1GB) if i was just to connect a pc to the end rather than the 8-port hub.

ajay

Justa, I am not sure what Auto-X is... do i need to use a crossover cable to connect 2 switches?

ajay

Bonjour Glen,

And now, reading your reply, I'm wondering how operates 1G in full- duplex if the all four pairs are used at the same time. The Ethernet

For the Ajay question, I'm also wondering what is the impact of Master and Slave configuration with 1G?

Best regards, Michelot

Orchid wrote: (snip)

Just to be sure, the twisted pairs are on pins (1,2), pins (3,6), pins (4,5) and pins (7,8)?

I have had cables where some didn't make contact some of the time, such that it would work plugged into one device and not another device.

Also, the PC you say it works is also running at gigabit speed?

Have you tested with the two switches close together with various cables?

-- glen

It is not easy, but it is possible.

Each end has to subtract the signal that it is sending from the signal on the pin to detect the signal it is receiving.

It is the same problem that speakerphones have.

Even more, gigabit has to subtract any echoes from impedance discontinuities along the cable. It takes a lot more processing than previous ethernet standards.

-- glen

Bonjour Glen,

Thanks for that particularity I missed.

I remember that. And this practise is also used in microwaves to transmit the bidirectional signal along the feeder (large coaxial).

OK, and now I see that in the section 40.1.3 of 802.3:2005 (sorry, I am much standard): "The use of hybrids and cancellers enables full duplex transmission by allowing symbols to be transmitted and received on the same wire pairs at the same time" (in baseband, not like in

Thanks for that, Michelot

I will try this out later today and report back... thanks again for all your ideas and help.

Hi Folks...

Ok, I did a whole bunch of additional tests today, not sure if this is going to help.

Firstly I bought 3 good Quality Cat 5e patch cables and 1 Crossover cable, these were tested to see if they work and they are fine.

2) I tried connecting the crossover cable to connect the 2 switches, and got no response whatsoever.

I really appreciate all the help folk have provided so far... thank you for your time.

(snip)

Does it have all four pairs? Many crossover cables don't.

I suppose it is possible that it isn't supported, but as I understand it, it is common for gigabit to work with crossovers as long as all four pairs get to the other end.

-- glen

yes, the cross over cable has all 4 pairs connected.. i tried it with a cable tester and all seems ok..