One fast network card or multiple network cards?

Redundency, failover and loadsharing over multiple nic cards, diverse routing, multi-homing are good examples of when to use 4 NIC's over one "fast" one. Even 4 10/100 NICs won't give you full Gigabit capability.
If you have limited slots on the board, you would want to conserve slots and use one NIC.

it would mostly depend on the type of network you want to setup and the type of service you are going to provide..
if u want to setup a blazing fast network with lots of users....u can go for multiple cards...if u want to provide complete fault tolerant system with 24x7 operation in that case also u should go for multiple nics.

but for simple network, extra cost is not justified.

have a look at this.
http://www.dlink.com/products/adapters/dfe570tx/

hi as,
This is very good query you had.
See the decision of putting one high throughput card or four normal card in the box depends on many situations. There are many conbinations you could have.
1. If you have server and your lan do not have more than 50 boxes connected to it then you should go for 2 100 mbps cards. These will provide you falt tolerance for connectivity in case of hardware (Lan Card) failure or software errors(ip-addressing/TCPIP settings).

2. If your are having more than 100 boxes connected to your server then you should not take the chance of it. There should be more than one lan card and they must be of Intel/3Com/Cisco/Avaya etc.
N.B. in any of the aboue situations, you never go for 10/100 mbps cards and the internetworking  device must be swithch rather than a hub.

3. If you are using peer-to-peer networking (workgroup kind of thing) and you do not have more than 20 boxes connected to your workgroup file server then you should go for even one 100 mbps card or 2 10/100 mbps cards. In first one you will not have fault tolerance but you will get it in later one.

Keep in mind always, the effect of downtime of your server/file server/network for you.

Putting more than one lan card will not only give more througput for your lan but also manage to boost confidence in you in case of any thing goes wrong with any one the cards.

waiting for your comments,
vxlil

What throughput do you need?  You'll only really see the benefit with gigabit if you start transmitting huge files between machines.  It won't make a difference if you're simply sending lots and lots of smalll files.

My server is a part of the domain and has a one 10/100 Intel NIC.
Throughput of the single client with 10/100 NIC is 24Mb/s.
Throughput of the server with 1 client connected - 24Mb/s.

Throughput of the client when 10 clients are working simultaneously is going down to 16 Mb/s.
Throughput of the server with 10 clients connected is going up to 72Mb/s.

My Lan is 100. Protocol is http.
Each client is downloading about 50 mb per session. Data is splitted to the small junks.
So, what is the best solution ?
I am increasing points to 500.
Thank you.

I meant 50 MB per session.

hi assas,
as per your discription given above still situation is only transperent from one side for me.... as I still don't know what kind of internetwroking devices you are using in you lan setup. I also don't know the ip-addressing policy and DHCP/DNS deployment at your site. Still I have lot of things to suggest you to resolve this probleam.

Hardware:
1. If your are using HUB (10/100) and any one of the client having 10 mbps lan card then you have to change the lan cards of your client boxes too. Even a single 10 mbps lan card brings your your whole network HUB to 10 mbps bandwith. So plz check wether you are having any of the lan card with 10 mbps
2. If your are too crazy for the speed then you need switches. If you are having HUB in you lan then plz replace the HUB with same capacity switch (capacity mean  no of ports). As if you might be awaire of the fact that HUB divides the input of the one port and passes it to all the ports. Suppose you have 8 port hub and all the client boxes having 100 mbps cards, still in this situation you have only 12.5 (10 approx) mbps throughput from all the ports. But if you replace the HUB with same no. port switch the the throughput will remain 100 mbps from each port. Switches creates a vertual lan in between the ports and make the data transfer point to point, which gives you maximum throughput.

Software:
1. Use DNS and DHCP in you lan
2. DHCP helps you to manage all the ip-address stup automatically.
3. DNS will take the help of DHCP and both work together to reduce the broadcast traffice of the lan which improves the througput of the lan. Thiw will avoid unnecessory usage of lan bandwidth by broadcast traffice.
4. Try to implement only TCP/IP, as you are using http, there is no sense to use netbiue.
5. Performance tuning of web server is also crusial in this kind of situation if you are using any web server viz., IIS.
reply me with my name as vxlil
waiting for comments
bye
:)
vxlil

vxlil,
I am using switches(no hubs), all client machines are DHCP, the server - fixed IP. All macines with 10/100 NICs. DNS is configured properly.
I am using http but my server is not a WEB-server.

My problem: when more than 10 clients connected - user expirience is bad(time of preload is growing up).  Server's throughput is about 75Mb/s (which is maximum in 100 LAN, I guess).

How can I improove my performance ?
High speed adapter, adapter with extended buffer, multiple NICs ?
Thank you in advance for your help.

>>I am using http but my server is not a WEB-server.
????

u can break the network in segments by putting two nics i nthe server and then connecting half machines on other part.
to allow communication between machines connected to diff end, u'll neeed to setup forwarding on server, which is not required here i guess since the client to client comm is not in basic requirements.

segmenting will divide your bandwidth physically into two networks thus almost double up your performance..

If you don't have gigabit switch ports, then the immediate, least expensive solution is to put two nics in and loadbalance.

Thank you all for your help.
Special thanks to vxlil.