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Using more than one network card in a server.

We have a rather basic network setup (70 PC's running 2000 or XP) and a single Windows 2003 domain controller.

Our server has two 1GB network cards, although at present one is disabled. In the past I have come accross servers running multiple NICS, although they have always been used to service different subnets.

Somebody has told me that it may be possible to use both my NICS in the server to boost network performance within my domain. This brings me to my 2 very simple questions:

1. Is it possible to do this without having to divide the network into different subnets?

2. If so, can you point me towards any resources which desribe how to do this.

Hope you can help.


1 Solution
In 2000 you couldn't do it.


I haven't seen anything about it in 2003.  Even if it were possible, a gigabit nic will almost always handle any IO a switch can throw at it, unless you have a hefty switch.
You are basically asking about a network bridge - it's an old concept that some time back was the due of a dedicated hardware.  With today's (& yesteryears') processors you can achieve this with a PC and a couple of NICs. As your server is already serving 70 PCs and has two GB network cards, I would urge caution if you are considering configuring the server to perform the task.  As your segments will all be on the same IP logical segment, I would advise using a seperate machine to perform the bridge.

Microsoft's overview with embedded link to how to create a bridge:
I haven't actually used 2 nics this way but providing that they are allocated IPs within the iprange of your dhcp server or the static ip of the 2nd nic is on the same subnet I don't see why not. I would actually suggest static ips and direct a few heavier users to one nic by IP rather than name and leave the other one to balance the load.

Not sure where to direct you on the net but if you are running dhcp, just enable it. If you are running static then copy the settings from the other nic remembering to give it a seperate IP address. To make sure the 2 nics are load balancing you can always monitor the traffic from both nics in network connections.
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Does the software for the NICs have a network teaming option?
metamaticAuthor Commented:
Don't know! The machine is a Dell Poweredge 6650 but I'm at home and it's not letting me dial in and check!
Tim HolmanCommented:
There are a number of ways to do this, as per:


We call this network card teaming.

In practise, I have NEVER had to improve server performance by adding an additional network card, as you very rarely use as much bandwidth as you think you do on a network.  Besides, if you were to use 2 GB network cards as a performance booster, then you would need an expensive switch that would support these and virutalise them into a single logical interface.

For 70 PCs and a single W2K DC, I would seriously just forget about this, and just buy some more memory and/or faster/bigger hard disks for your DC.
You could conceivable combine the two 1GB links into a ~2GB "Etherchannel" (okay, I'm a Cisco guy) provided that your NIC's support this, and both uplink to a Cisco or comparable hispeed switch.

Realistically tho, for 70 clients on a flat Windows 2003 LAN, you won't get a real ROI.  Why not have a peek at the "Network" tab in your 2003 Server task manager and profile/trend what your NIC usage actually is.  If you're not maxing out the 1GB you have now, increasing it to 2GB won't do anything for your networks performance.
Yes.  According to the 6650 specs, the software will provide teaming for you:
In the past I have often found that two network cards are slower than one.
Why ?  Best guess was that the interrupt time to transact bewteen NIC's and BUS ( or whatever )was the bottleneck. Although it is not very scientific I would do some benchmarks with one card enable and then compare to two cards enabled ( bridged - if possible ) and also compare with two NICs enabled ( separate subnets ). Then try the other NIC by itself - who knows it maybe faster than the current one you are using.

Since NIC technology and PCI technology BUS technology has changed so much and so quickly it really is very hard to know whether or not one card is better than two for YOUR network in YOUR server. I would use trial and error ( benchmarking all the way ).

If anyone has a good LAN Benchmarking utility please advise.

<< 1. Is it possible to do this without having to divide the network into different subnets? >>

Generally speaking, even for 2003, NO.

However, in any network of 70 PCS, there might be accounting and executive departments with sensitive information, whom the other users don't need to access.  SO what is wrong with two class Cs?  YOu can set the sensitive people up on 192.168.2.x and the normal people up on 192.168.0.x  -- and you can also split printers similarly.

However, all this done, I doubt it will make much difference in throughput.  Now if you had everyone on 100 Mbit cards and you put in a 1 GB switch, where everyone went into that one switch, and made the link from the switch to the server as 1GB too, THEN you will see a performance increase, for sure.
>We have a rather basic network setup (70 PC's running 2000 or XP) and a single Windows 2003 domain controller.

No BDC????
You should analyze the network traffic, and split the traffic to multiple servers. It is unlikely that the nic limits your network performance.
The newer Dell servers have an Intel driver that bridges the NIC's to achive what you're after. Check if Dell's support site has the software for your 6650. We have two 2800's running both nic's this way. The software also give you the option for fail-over versus bridged.

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