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Connecting 2 PC's via crossover for 2gbit goodness.

Last response: in Networking
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December 14, 2006 5:06:38 AM

I'm not quite ready to invest in upgrading my entire wired netowrk to 2gbit, but i'd like to take some of the first steps. Here is what i would like to do:

I would like to buy two 2000mbit ethernet cards and install them on two computers that i copy flies between on a constant basis (rather large files i might add). I was thinking i could connect them via crossover cables so that i can avoid having to dish out $50+ for a good 2gbit switch (for now at least).

I will leave my old 10/100 cards in place and enabled, so that my computers can access the rest of the network and the internet.

Since the computers will be connected both through thier crossover 2gbit and regular 10/100, will windows favor the 2gbit when transferring between the two computers? Will i have to change some settings to force it to use the 2gbit whenever possible?

I already have a laptop that is sometimes connected via 10/100 and wireless 54mbit, and i notice that it *does* favor the wired lan most of the time. I'm jsut wondering how this will work with my desktops.
December 14, 2006 12:01:30 PM

This "2 gigabit" business is marketing crap. All they're doing is counting the throughput in both directions -- full duplex 1 gigabit -- and calling it 2 gigabit. There's no half-duplex in gigabit anyways, so all gigabit could be called "2 gigabit" accordingly. It serves no purpose other than to make some products falsely look faster than they really are and hence more desireable. By falling for this marketing crap, you could be falsely raising your prices by limiting your choices to those products which are advertised so.

You can get a decent GbE switch for $30 or less.
December 14, 2006 1:51:51 PM

Quote:
This "2 gigabit" business is marketing crap. All they're doing is counting the throughput in both directions -- full duplex 1 gigabit -- and calling it 2 gigabit. There's no half-duplex in gigabit anyways, so all gigabit could be called "2 gigabit" accordingly. It serves no purpose other than to make some products falsely look faster than they really are and hence more desireable. By falling for this marketing crap, you could be falsely raising your prices by limiting your choices to those products which are advertised so.

You can get a decent GbE switch for $30 or less.
Or, draxsath, putting it another way, since 1Gb = 2Gb, does that change your cost equation? After all, a crossover cable will cost you in the vacinity of $15 - 20 bucks retail (your price may vary, especially if you don't buy retail).

Not to mention all the configuration hassle of trying to get Windows to do what you want with your two NICs.
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December 17, 2006 12:53:04 AM

I think the answer to your question of 'favoring' the 10/100 vs the gigabit connection can be solved by how windows file sharing is set up.

It has been many years since I've tried anything like this but, I think what you want to do is 'bind' file (and printer) sharing to the gigabit adapter.

I think this will work:
Under 'network connections' of the control panel you will find 2 network adapters (one 10/100 and the other the new gigabit) Right click on the 10/100 card icon and go to properties. From the main tab, unclick microsoft file and printer sharing item in the list.

The problem with doing this is that it will disable file sharing to any boxes connected by the 10/100 NIC. The only way that I know around this is to use a gigabit switch, eliminating the 10/100 cards.
December 18, 2006 4:18:48 PM

Forgot to add, most Gigabit hardware is auto-MDX anyway. No need for a crossover cable. Just use a regular cable.
December 20, 2006 1:35:38 PM

No idea how windows handles two NICs.

Get yourself the following scrapping your current NICs:
Dlink 530T full duplex giglan NIC with jumbo frame support - $20
Dlink 530T full duplex giglan NIC with jumbo frame support - $20
Netgear GS108 8-port gigaswich with jumbo frame support - $60

There, now your LAN will run @ gigaspeeds and you can use jumbo frames which on my LAN have me a huge increase (switching from 1500 byte to 4088 byte frames), see the bottom of my post.

The 530T is a cheap PCI 2.x card that'll do 4k or 9k jumbo frames and does pretty decent speed-wise (as good as any onbord gigaNIC I've seen.
The GS108 is a great switch and does up to 9k jumbo frames. You can probably get the cheaper 5-port version (GS605) which also does jumbo frames and be just fine).

I have some older hardware (linux is running on a 1900+ athlon xp nforce2 based board and my win box is a 3200+ athlon xp nforce2 based board) which may explain the giant boost of larger frame size. Here are the results of my tests moving a large file from the win to linux and from linux to win. I've concluded that my network would HUGELY benefit from a 4k MTU size. Here are the data:

Test Large file, 1,048,522 kb xfered via Samba
Both NICs running @ full duplex 1 gig mode

[code:1:2a55cac6de]mtu=1500 time (sec) MB/sec Mbps
linux to win 59 21.2 170
win to linux 94 13.3 107

mtu=4000
linux to win 51 24.6 197
win to linux 46 27.2 218

mtu=9000
linux to win 57 22.0 176
win to linux 49 25.6 205[/code:1:2a55cac6de]

My conclusions
[code:1:2a55cac6de]4k vs. standard % Change
linux to win 16%
win to linux 104%

9k vs. standard
linux to win 4%
win to linux 92%
[/code:1:2a55cac6de]

As you can see the 4k frame size doubles my win-to-linux transfers and give nearly a 20% boost to the linux-to-win transfer. I did additional tests with a couple gigs of small files which I didn't post here. The results were similar in that the 4k frame size gave the best performance.

What's striking to me is that my network is not even close to the theoretical limit of gigalan (1000 Mbps). I just started a thread (here) soliciting others with GigaLANs to post their results. If you have one, please reply there.
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