Crazy idea on Gigabit

[thesix]

I am thinking about a direct connection (crossover cable) between two Gibabit cards on two workstations
Both workstations have another 100Mbit card which connect to the outside world.
The purpose is having high speed data sharing between the two without using a Gigabit switch/hub.
--- is it possible ?

 

[Transition]

Yes it's possible. But the question is, why?

 

[thesix]

Because Gigabit eithernet switch is expensive ( right? ) , while Gigabit card is cheap ($30),
and all I need is high speed between these two workstations (file sharing).
I can go to the outside world using the existing 100Mb NICs and switch.

Does that make sense ?

thank you for your response.

 

[MichaelD]

It only makes sense if you really need to transfer 100GB of information and can't afford to wait an hour instead of about 40 minutes.

You can connect two PCs with a crossover cable and I THINK you only need to have TCP/IP loaded...not sure...might need another protocol...it's been awhile since I've done this)

But the two 10/100 Nics connected with a shorty 6-foot cable will transfer a Gig in an eyeblink, pretty much.

I guess what I'm trying to say is: there's "Yes, it will work" and then there's "Yes, it will work, but why do you need to?"

 

[thesix]

> It only makes sense if you really need to transfer 100GB of information and can't afford to wait an hour instead of about 40 minutes

Huh? How did you calculate this? Have you tried transfer 100GB of data over 100Mb NICs?

Sustained throughput between 100Mb NICs is less than 10MB/sec.
I expect 50MB/sec sustained speed between 1000Mb NICs.

When sharing data between two hosts, they act like hard disks.
Let's say the real hard disk can only handle 20MB/sec read/write throughput,
I still get double the speed.

Are you suggesting 2x-3x faster in real work is not worth the extra $60-80$ ?

Thank you for your response.

 

[MichaelD]

Originally posted by: thesix
> It only makes sense if you really need to transfer 100GB of information and can't afford to wait an hour instead of about 40 minutes

Huh? How did you calculate this? Have you tried transfer 100GB of data over 100Mb NICs?

Sustained throughput between 100Mb NICs is less than 10MB/sec.
I expect 50MB/sec sustained speed between 1000Mb NICs.

When sharing data between two hosts, they act like hard disks.
Let's say the real hard disk can only handle 20MB/sec read/write throughput,
I still get double the speed.

Are you suggesting 2x-3x faster in real work is not worth the extra $60-80$ ?

Thank you for your response.

I wasn't scientific or exact in any sense of the words. I was being "real world and practical" if you will.

If you are planning on INTERNALLY transferring that much data on a basis regular enough to justify the expense, then hey man; go for it!

But AFA you internet connection goes, you'll always be limited by your DL speed, which I highly doubt is faster than 10 mbps, if half that. Mine isn't, so my 10/100 NIC is just dandy.

I don't transfer anything bigger than a CD Rom on any sort of regualr basis...when the need arises, I go have a beer or four, come back and it's done. I don't need Gigabit anythign right now.

 

[thesix]

I am NOT going to use Gigabit for internet surfing --- I am not that stupid

The only reason I create this thread is to confirm that I can use 'crossover' between Gigabit NICs
as we did with 100Mb NICs, just to save the money of a Gigabit switch for now.

Thanks.

 

[MichaelD]

Originally posted by: thesix
I am NOT going to use Gigabit for internet surfing --- I am not that stupid

The only reason I create this thread is to confirm that I can use 'crossover' between Gigabit NICs
as we did with 100Mb NICs, just to save the money of a Gigabit switch for now.

Thanks.

A NIC is a NIC. You can use a Xover cable...the cable has no idea what it's connecting to. However, it's gotta be a Gigabit-rated cable!

 

[ScottMac]

Also be aware that a Gig crossover cable is not pinned out the same as a 10/100 crossover.

Google will be your friend .... Cisco "fer sher" has the pinout posted.

Good Luck

Scott

 

[SMKungPao]

Be sure to use CAT5e cable.

 

[thesix]

Thank you for all the advices !

 

[Santa]

If you have say computer A and computer B.

Put Computer B's GigE NIC IP address into the host file of computer A and Computer A's GigE NIC IP address into the host file of computer B.

That way every communication sent via Netbios name resolution will go over the Gigabit links.

So if you typed \\ComputerA\Share you will get ComputerA resolved to it's Layer 3 address of the GigE link.

Easy way to build a small mini core network.

 

[cmetz]

thesix, all 1000BaseT equipment is auto-crossover. So just connect two 1000BaseT NICs with a straight cable and they'll sort it out for themselves.

I recently bought a Hawking HGS-4T 4x10/100/1000 switch from Amazon for $80 shipped. I think their price varies slightly with... heck, I don't know why, but anyway, that's pretty cheap. That way you have one single Ethernet instead of one gig one and 10/100 one going to the outside world.

Oh, and if you're trying to maximize PC to PC transfer performance, get a decent gigE NIC. On a cheap side of the scale, the Intel Pro/1000MT is good and circa $41 at Newegg. The really low cost boards based on the NS DP83820 chip have noticeably worse performance - not worth it to save $10ish IMO.

 

[thesix]

>> all 1000BaseT equipment is auto-crossover.

Really? That's interesting. Should have done more homework

I am thinking of Netgear's GA302T, any comment ? ( I don't have 64bit PCI anyway, no need for highend card.)

Thanks a lot.

 

[ScottMac]

NO. *ALL* Gig Ethernet is NOT "auto-crossover."

Some / much of it will configure for straight-through or crossover, but it's not universal. The most notable exception is Cisco. Much, if not all, Cisco stuff requires a crossover cable to go switch-to-switch with copper.

FWIW

Scott

 

[cmetz]

ScottMac, you're right, I stand corrected. Learn something new every day

IEEE 802.3-2002 40.4.4 (Automatic MDI/MDI-X Configuration) says "Implementation of an automatic MDI/MDI-X configuration is optional for 1000BASE-T devices." Every 1000BaseT device I've ever used has done it, and I knew it was in the spec... I didn't know it was optional.

Interesting that Cisco of all players doesn't do it. Even the $25 National Semiconductor NICs and the cheap Hawking switches do it.

 

[spidey07]

I thought there was some concern on noise and chipsets the did auto MDI/MDI-X detection?

Don't know, It'll be a sweet day when every single network node detects MDI/MDI-X, 10/100/1000 half/full flawlessly.

LOL!
<---waiting in hell and its still not chilly

 

[cmetz]

spidey07, if I'm reading right, the MDI/MDI-X is part of NWay, and so there should be no reliability issues with that negotiation that don't also affect the general link negotiation. And these days, with modern equipment, autonegotiation mostly works.

 

[spidey07]

I'm with ya there Cmetz. Its A LOT better than it used to be.

 

[trikster2]

I've used point to point with a xover with great success in the past. No reason it should not work. Multiple NICs add a new twist to the mix but should be doable.

Standard 32 bit PCI Gig will only net you twice to three times the speed of 100 Base T. Wait for Intel 865/875 CSA or NForce 3 solutions for better performance.

But why not do it right? Gig switches start around $90, plus you'll have room for expansion

Hawking 4 port gig switch $97

Linksys 5 port Gig Switch $129

Linksys 8 port Gig Switch $160

 

[Barnaby W. Füi]

Bah, who needs a switch? Just pop off the plugs and start twisting wires together

 

[mcveigh]

cmetz-- how is that gigE switch working for you? I thought about getting one to familiarize my self with gigabit

 

[cmetz]

It's okay. It really does have enough switching capacity (I tested) and it seems to do all the autonegotiation right, never had any problems. It's just like your average SOHO switch except this one does 10/100/1000.

My only issue with it -- and this is 'cause I'm spoiled by higher-end stuff -- is that it will not carry even a byte more than 1500 in frame size. It is very common that gigE equipment support "jumbo frames" up to 8-10k (9000, 9180, and 9200 being common limits), as this helps performance at gigabit speeds (otherwise you need to do interrupt coalescing, which introduces extra latency, or you're going to be in for a world of hurt on architectures like PCI). It's also common that modern Ethernet equipment will support 1504 byte frames to let you slip in an 802.1Q VLAN tag. The Hawking switch allows neither. In some fairness to the Hawking folks, 1500 is the standard and they comply with it - >1500 is vendor enhancement.

Can't beat it for the price though. And being 10/100/1000 means you can gig link a couple of PCs and connect to the outside world and such as part of the same Ethernet.

 

[trikster2]

Originally posted by: cmetz
It's okay. It really does have enough switching capacity (I tested) and it seems to do all the autonegotiation right, never had any problems. It's just like your average SOHO switch except this one does 10/100/1000.

My only issue with it -- and this is 'cause I'm spoiled by higher-end stuff -- is that it will not carry even a byte more than 1500 in frame size. It is very common that gigE equipment support "jumbo frames" up to 8-10k (9000, 9180, and 9200 being common limits), as this helps performance at gigabit speeds (otherwise you need to do interrupt coalescing, which introduces extra latency, or you're going to be in for a world of hurt on architectures like PCI). It's also common that modern Ethernet equipment will support 1504 byte frames to let you slip in an 802.1Q VLAN tag. The Hawking switch allows neither. In some fairness to the Hawking folks, 1500 is the standard and they comply with it - >1500 is vendor enhancement.

Can't beat it for the price though. And being 10/100/1000 means you can gig link a couple of PCs and connect to the outside world and such as part of the same Ethernet.

Hey CMETZ

Refresh my rusty gigabit memory: Can any windows OS support jumbo frames? Also did you look at the $130 linksys switch? Does it support jumbo frames?

 

[cmetz]

trikster2,
>Can any windows OS support jumbo frames?

I don't do Windows, I really don't know. My GUESS is that 2K/XP can, and older versions are solidly a who-knows. Older than 2K/XP the network stack probably isn't going to be able to deliver nearly as good performance anyway. I do know that recent gigabit performance demos MS has done have used jumbo frames because without them it can't deliver enough performance, so they're doing it somehow.

>Also did you look at the $130 linksys switch? Does it support jumbo frames?

No, I didn't. I saw the Hawking announcement at CES (?) and then a month later when they hit the street, grabbed one. The Linksys product came later and I really don't know what it is and isn't capable of. My guess is that it can't do jumbo frames, but 1504 it might or might not. The low end switches pretty well support the minimum number of features necessary to comply with the standards, and not always even that much.

Remember, jumbo frames are not required by the standard, they're a vendor extension, that basically all NIC vendors and higher-end switch vendors support in some flavor or other (the actual jumbo limit varies, but circa 8k they can all do). The low end guys are new to the game and probably are doing the most minimal job possible. And I'd be more upset about this, but, you know what? That's exactly how they get it so cheap. If I were buying a gigabit switch costing a few thousand $$, I'd set totally different standards, but for $80, you get what you pay for - no more, and hopefully no less!