Gigabit networking, nic-to-nic

[StraightPipe]

What kind of cable?

I've been told many different things.

I think cat5e will be ok, but do i need xover or straight?

i've been to xover here

and straight cables here

can anyone tell me which is right?

is cat5e going to be ok (my max transfer rate on my RAID drive is 85MB/s=680mb/s, i'll be happy if that drive is slower than my network!)

 

[sswingle]

Cat5e will definately be ok.

I vote for xover cables PROPERLY made. Since it uses all 4 pairs, both sets need to be crossed. Most people (myself included) get lazy when they make cables and only cross one pair.

 

[bex0rs]

A straight through cable is fine for nic-to-nic gigE.

~bex0rs

 

[StraightPipe]

Originally posted by: bex0rs
A straight through cable is fine for nic-to-nic gigE.

~bex0rs

have you done this before? can you explain why? (or link me)

What about you, pwddesign?

(I do have proper xover)

 

[StraightPipe]

Aha,
if all else fails, read the manual.

Page 6, TRENDnet Multi-Langauge User's GuideYou can use standard or crossover cable to connect the switch's MDI-X or MDI-II port... NWay Gigabit Ethernet Card will adjust the correct medium configuration automatically

I guess you were both right.

 

[p0lar]

StraightPipe:

a standard crossconnect cable for 100BaseT will *not* work. Period. Those who tell you it will, are positively wrong.

1000BaseT does not use separate send/receive pair!!!

It uses all four pair; however, it sends and receives concurrently on each pair across all four. Use a Cat5e interconnect cable and you'll be fine. I've tested this on switches, workstations, servers - you name it. It works because it follows gigabit-ethernet SPECIFICATIONS.

If you use a crossconnect cable on a 1000BaseT interface, it will most likely fall back to 100BaseT and operate on those specs. Don't be fooled by those who say 'it works' because honestly, for 1000BaseT, it DOES NOT WORK.

 

[StraightPipe]

the nic manual says that it works., I just plugged it in and it works, dont be fooled by me!

 

[p0lar]

"it works" What works? The crossconnect? If it works, then it's because the card isn't behaving by copper gig-e specs.. also, if the crossconnect works, the interconnect should work as well. I could see the crossconnect working in 100BaseT mode, what's your throughput on that link with a crossconnect? I bet it's not 1000BaseT...

Here's how it works:

100BaseT Pinout for crossconnect:

1 -> 3 \
2 -> 6 / Send on this pair
3 -> 1 *\
4 -> 4
5 -> 5
6 -> 2 */receive on this pair
7 -> 7
8 -> 8


Ok, this is fine for 100BaseT because it sends on one pair and receives on the other.

On 1000BaseT, here's how data is transmitted:

1 -> 1 \
2 -> 2 / Send/Receive on this pair

3 -> 3 \
6 -> 6 / Send/Receive on this pair

4 -> 4 \
5 -> 5 / Send/Receive on this pair

7 -> 7 \
8 -> 8 / Send/Receive on this pair

It sends and receives on each pair so if you cross the 1/2 pair with the 3/6 pair the 4/5 will stay intact as will the 7/8, but unless each card knows to crossconnect those (which wasn't in the original 1000BaseT specs) then it's a no-go at 1000BaseT; HOWEVER, if it falls back on 100BaseT it will most definitely work.

From an engineering standpoint, anything is possible, but it just wasn't spec'd this way.

Get some throughput reports to confirm one spec or the other.

 

[StraightPipe]

Originally posted by: StraightPipe
Aha,
if all else fails, read the manual.

Page 6, TRENDnet Multi-Langauge User's GuideYou can use standard or crossover cable to connect the switch's MDI-X or MDI-II port... NWay Gigabit Ethernet Card will adjust the correct medium configuration automatically

I guess you were both right.

did you read this post?

 

[gunrunnerjohn]

Originally posted by: StraightPipe

Originally posted by: StraightPipe Aha, if all else fails, read the manual. Page 6, TRENDnet Multi-Langauge User's GuideYou can use standard or crossover cable to connect the switch's MDI-X or MDI-II port... NWay Gigabit Ethernet Card will adjust the correct medium configuration automatically I guess you were both right.

did you read this post?

I just picked up a pair of gigabit boards to connect my two primary machines for speedy backup, and I see the same language in them, so I'll just crimp together a standard CAT5e cable, that way it's useful for other things. 😀

FWIW, I was surprised that Lowe's has CAT5e riser cable for $0.07/foot in 1000 foot rolls, and only $0.09/foot for any length. That's WAY better than the guy at Radio Shack, they wanted $60 for 100 feet of CAT5e! :Q

 

[Garion]

Originally posted by: gunrunnerjohn

Originally posted by: StraightPipe

Originally posted by: StraightPipe Aha, if all else fails, read the manual. Page 6, TRENDnet Multi-Langauge User's GuideYou can use standard or crossover cable to connect the switch's MDI-X or MDI-II port... NWay Gigabit Ethernet Card will adjust the correct medium configuration automatically I guess you were both right.

did you read this post?

I just picked up a pair of gigabit boards to connect my two primary machines for speedy backup, and I see the same language in them, so I'll just crimp together a standard CAT5e cable, that way it's useful for other things. 😀

FWIW, I was surprised that Lowe's has CAT5e riser cable for $0.07/foot in 1000 foot rolls, and only $0.09/foot for any length. That's WAY better than the guy at Radio Shack, they wanted $60 for 100 feet of CAT5e! :Q

Oh boy, here we go again..

1: If it's riser cable, it's solid core, not meant for patch cables. It's meant for in-wall wiring not to be moved much - Solid core is FRAGILE and will probably cause utter chaos in your network eventually.

2: Very, very few people can crimp cable to Cat5/5E/6 specs to get good, solid 100BaseT connections that will work for the long-term. When you're dealing with gigabit, it's even worse.

You can buy machine-made, stranded Cat5/5E/6 cables cheap nowadays - Under a buck, if you shop around. It's NOT worth making your own when you can get something that you know will work.

- G

 

[gunrunnerjohn]

I have crimped 100's of Ethernet cables without a single problem cable. It's not that difficult with the proper tools and a little skill. I know the cable is solid wire, but it's going to be strung between two machines and not moved after that. FWIW, I have several solid conductor cables that have been around for years, and they are still going strong. Not everyone has ten thumbs, you need to get out more.

 

[Garion]

Originally posted by: gunrunnerjohn
I have crimped 100's of Ethernet cables without a single problem cable. It's not that difficult with the proper tools and a little skill. I know the cable is solid wire, but it's going to be strung between two machines and not moved after that. FWIW, I have several solid conductor cables that have been around for years, and they are still going strong. Not everyone has ten thumbs, you need to get out more.

Gee. You're right. I've never done this before. Lessee.. In my last job, I supervised the construction of two data centers and the ground-up wiring of four major office buildings - I'd say that the contractors working for me wired 10,000+ network drops - Something like 400 miles of cable. I've seen literally dozens of major network problems that took down major applications caused by layer 1 / cabling problems. I know that, when it comes to your cabling plant, you let the pros do it, since that's what they do best. And the pros tell me not to make my own patch cables, unless it's absolutely necessary. They don't make them, they use machine-made ones.

Yes, you can make cables and be successful. I've done it myself when I had no other choice. A lot of people do it all the time. But for me, it's not worth it when machine made cables are so cheap and nearly always work.

- G

 

[nightowl]

I make cables an almost a weekly basis at work and almost always they are fine. Now, this is not just plugging them in and saying that the cable works. I use a Penta-Scanner to test every cable and I have yet to make a bad cable. I do take my time to make sure that the cable is made correctly and to spec though.

 

[gunrunnerjohn]

I've seen literally dozens of major network problems that took down major applications caused by layer 1 / cabling problems. I know that, when it comes to your cabling plant, you let the pros do it, since that's what they do best.

Perhaps, some of these problems were due to allowing the "pros" to do the work.

I didn't mention previously, I've also had several bad patch cables that were right out of the shrink wrap, I guess the machine was having a bad day. As far as having the "pros" do the wiring, I've fixed plenty of wiring at client locations after the "pros" got finished. It seems that some of the "pros" don't understand the concept of correctly wiring the pairs, not to mention proper crimps on the connectors. 😀