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Gigabit Ethernet

Community Veteran
Posts: 1,236
Registered: ‎02-08-2007

Gigabit Ethernet

I am planning to hopefully soon change my switch and the cards in 2 of my computers to gigabit. Do I need cat 6 cable? I currenlty have cat 5e through the house. It would not be difficult to change but I hate working with the solid core cable so would rather keep my existing cable. The longest length of cable that would be involved in the gigabit connection is about 15 metres. Thanks, Sean.
10 REPLIES
Community Veteran
Posts: 14,469
Registered: ‎30-07-2007

Re: Gigabit Ethernet

Cat 5e should work fine for your distances.
Community Veteran
Posts: 1,236
Registered: ‎02-08-2007

Re: Gigabit Ethernet

Thanks. Actually just seen that in an internet article after posting. Good news!
Community Veteran
Posts: 14,469
Registered: ‎30-07-2007

Re: Gigabit Ethernet

Also your PCI bus is likely to reach its limit before your network does. You may get 100MB/s out your Gigabit link (all connections being good) but PCI maxes out at about 127MB/s but that is shared between other PCI devices so you won't reach the network capacity.
Now if you were using PCI-E then there would not be an issue.
Then you've got the issue of how fast you can get the data off and on your disks and to/from your NIC.
robthomlinson
Newbie
Posts: 2
Registered: ‎21-08-2007

Gigabit ethernet switch

decided that my old 10baseT linksys switch is now getting a bit old in the tooth, and given that some of the hardware I am now running can use 1000baseT I am looking to put in hardware that will support it. 
Anyone got opinions on a good switch to go for - I need 10 ports minimum
[Moderators note by James_H : Merged into ongoing thread discussing GB Ethernet - save any duplication of comments/thoughts  Wink]
Community Veteran
Posts: 1,236
Registered: ‎02-08-2007

Re: Gigabit Ethernet

Quote from: Peter
Also your PCI bus is likely to reach its limit before your network does. You may get 100MB/s out your Gigabit link (all connections being good) but PCI maxes out at about 127MB/s but that is shared between other PCI devices so you won't reach the network capacity.
Now if you were using PCI-E then there would not be an issue.
Then you've got the issue of how fast you can get the data off and on your disks and to/from your NIC.

If PCI is only capable of 127Mbps why does gigabit PCI cards exist?
I do not have PCI-E and I have no plans or money to upgrade any of my motherboards for a while.
Community Veteran
Posts: 14,469
Registered: ‎30-07-2007

Re: Gigabit Ethernet

Gigabit Ethernet was not a practical option or even on the market when PCI was designed.
In any case they still run a lot faster than the existing 100Mb (note bits not bytes) cards, you just can't run it at it's maximum capability. I saw a 5 to 6 x speed increase when I tried a 100Mb & 1000Mb network between 2 PCs.
Community Veteran
Posts: 1,236
Registered: ‎02-08-2007

Re: Gigabit Ethernet

Quote from: Peter
I saw a 5 to 6 x speed increase when I tried a 100Mb & 1000Mb network between 2 PCs.

Was this while using PCI cards?
Community Veteran
Posts: 14,469
Registered: ‎30-07-2007

Re: Gigabit Ethernet

It was a few years ago so can't remember exactly. I think one was a server with on-board 10/100/1000 NIC and SCSI disks and the other was a PC with PCI but it may have been a 64bit PCI card rather than 32bit.
I didn't use a hub/switch either, just a x-over Ethernet cable between the two.
So probably not a good comparison to your set-up
Philbert
Grafter
Posts: 43
Registered: ‎26-08-2007

Re: Gigabit Ethernet

I was looking into this some while ago, and as I recall, in effect the electrical impulses carrying the data are conducted on the surface of the wires (it's all a bit quantum, I thinki).  But in practical terms, the upshot was that the wiring is very sensitive to being kinked, or bent.  Gentle curves are called for.  I also gathered that Cat6 cabling was ideal.  I didn't get round to impementing such a set-up, and I'm not in a position to vouch for the above.    But you may care to review the requirements yourself.
Denzil
Grafter
Posts: 1,733
Registered: ‎31-07-2007

Re: Gigabit Ethernet

Any high frequency electrical signal tends to get carried on the surface of the conductor - it's called the skin effect. The higher the frequency the greater the effect.
Yes, CAT 6 is ideal, but as Peter says, CAT 5e will work fine. It is not worth replacing the cable if it is already in place.