Gigabit crossover cable?

[CZroe]

My 820GB fileserver only has two clients, an 802.11g laptop and a 10/100 desktop. I don't intend to do anything about the laptop, but large multi-Gigabyte transfers will need to be made routinely with the desktop. Pricewatch says I can get two Gigabit cards for $30, and the employee price at CompUSA could get two Netgear ones for $60 (Anyone here work there? Get me a couple... 😉). Then there's the switch. Basically, $160 for the Linksys one isn't too much, but I'd have to call off the upgrade for quite a while if it is required.

I was told that Gigabit uses all 8 conductors and that there is no such thing as a Gigabit crossover cable. Does this mean that a switch IS required or that Gigabit cards simply do not need a crossover cable to function while directly connected?

Thnx!

 

[AWhackWhiteBoy]

i'm asuming here,don't quote me, but the cross over cables i've made in the past, the standard includes all 8 pairs so they are set and ready to go for future standards(gigabit). you can use any old crossover cable to do what you want to do. i've been out of the telcom loop for awhile,who knows, maybe they autosense that now too and you could be able to use a straight through.

edit: yea,i googled it.you should to. higher end cards autosense,but you may still need a typical cross over cable.

 

[mechBgon]

I'm using a Cat5e crossover cable to link two gigEthernet NICs at work (the 3Com gigE NIC on my K8V Deluxe, and a Intel :Q Pro/1000MT PCI NIC in my little nForce2 server system). I got the cable from Newegg, if that helps.

 

[moretoys]

Will the Gigabit cards really but you much for bandwidth sitting on the desktop pci bus running at 133 Mb/s? Or am I getting my bits & bytes mixed up 🙂

 

[n0cmonkey]

Originally posted by: moretoys
Will the Gigabit cards really but you much for bandwidth sitting on the desktop pci bus running at 133 Mb/s? Or am I getting my bits & bytes mixed up 🙂

I can't answer that, but generally gigabit cards are of higher quality than 10/100 cards. They typically have more buffer space and whatnot, so they can sometimes work better than 10/100 cards if you set them at 100mbit.

 

[AWhackWhiteBoy]

100mbits per second = 12.5 megabytes per second.
and thats peak, you never get the actual stated bandwidth. most decent modern hard drives can write at 45megabytes a second.

 

[CZroe]

Thnx. I realize that my PCI bandwidth is taxed and IE actually lost a really long post I made about it. 🙁

1000Mbps=125MBps (less than 33MHz 32-bit PCI's max of 133MB). That's shared with six of my seven hard drives in a RAID5 array so copying to/from the array over Gigabit would have a serious limitation (But it would still be way better than 100Mbps Fast Ethernet).

 

[Kwatt]

CZroe
You should not need a switch or a crossover cable. A patch cable will do. See below.
I don't have the data sheets for the other cards but I believe the gigabit spec calls for auto compensation.



mechBgon
You don't need a crossover cable. You can use a patch cable.

Quote from the Intel Pro/1000MT Data Sheet.
Dynamically tests and reports network problems (interrupts, error rate, cable length) and automatically compensates for cable issues such as crossover cable, wrong pin-out and polarity.




Kwatt

 

[sharkeeper]

Yes, as mentioned in the post above you do NOT need crossover cables with GigE peripherals! Just plug 'n go!

Cheers!

 

[AWhackWhiteBoy]

Originally posted by: shuttleteam
Yes, as mentioned in the post above you do NOT need crossover cables with GigE peripherals! Just plug 'n go!

Cheers!

not all are autosensing, only decent chips do that.

 

[CZroe]

Originally posted by: AWhackWhiteBoy

Originally posted by: shuttleteam
Yes, as mentioned in the post above you do NOT need crossover cables with GigE peripherals! Just plug 'n go!

Cheers!

not all are autosensing, only decent chips do that.

Yes, that is the way it is with 10/100 cards but can you confirm that that is the case for Gigabit cards? Only "no crossover required" guys are naming the cards they refer to while the detractors don't specify what they are talking about 😕

 

[mechBgon]

Thanks for the tip Kwatt 😎

 

[sharkeeper]

not all are autosensing, only decent chips do that.

Works on el-cheap-o Netgear and Intel 1000MT desktop NICs just fine. 🙂

Cheers!

 

[AWhackWhiteBoy]

Originally posted by: CZroe


Yes, that is the way it is with 10/100 cards but can you confirm that that is the case for Gigabit cards? Only "no crossover required" guys are naming the cards they refer to while the detractors don't specify what they are talking about 😕

go to the maker's web site and find out the specs on your ethernet to make sure...

 

[ScottMac]

Not all GigE equipment will automatically do the crossover. Cisco, for example, does not.

A GigE crossover is different than a usual 10/100 crossover, in that all four pairs are crossed, not just pair 1&3 (1&2, 3&6).

Gig Crossover: pins 1->3, 2->6, 4->7, 5->8 (per Cisco's web site).

Good Luck

Scott

 

[CZroe]

Originally posted by: ScottMac
Not all GigE equipment will automatically do the crossover. Cisco, for example, does not.

A GigE crossover is different than a usual 10/100 crossover, in that all four pairs are crossed, not just pair 1&3 (1&2, 3&6).

Gig Crossover: pins 1->3, 2->6, 4->7, 5->8 (per Cisco's web site).

Good Luck

Scott

Thnx. I figured that it would either work with a standard crossover cable, not require one or require a hub/switch (Sort of how WiFi tries to force access point hardware when the cards can function as an access point with the software they withhold). Now I find out that it is none of these according to the standard. Thnx!