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Simon,
You should buy a ethernet card with a DMA channel. this should greatly off
load the CPU from working to put the data received into memory. 3com is a
good choice. If it doesn't say specifically it has DMA then it probably
doesn't.
The following are excerpts from an email that I sent recently. discussing
the use of TS in a similar situation but with a presumed network
configuration with a shared Internet connection.
Chuck Kaucher
//////////////////
Just want to make sure we understand each other. The real improvement or
relief from any CPU bottleneck is on the receiving machine. The benefit
on the dedicated Internet machine should be minimal since it is a dedicated
machine to processing the Internet connection.
Consider this: You are running a machine with TS4/TS2000i running realtime
computing the value of your indicators on every tick. That is a lot of
computing.
Without a Direct Memory Access(DMA) the CPU must ALSO unpack/compute/handle
the transfer of every packet of data to the main memory of the computer
while doing all that computing for your indicators
With DMA, All the CPU does is handle the interrupt that data is waiting on
the ethernet card and then instructs the card to load it into the main
memory. After the ethernet card uploads the data to the main memory it
tells the CPU it is done.
Now, I believe that 3Com and Intel and possibly other cards offer
management capabilities that work best when their cards are used among
several machines.
All of this helps relieve a bottleneck on your local network. I read
somewhere that the overhead of IP is so great in practice that it alone can
consume 50% of your bandwidth. This is mostly due to the variable size of
the data packets can be on average very small.
Suppose you have streaming radio for your kids, as I do. That is a
bandwidth hog. Add Data to network and possibly a Squawk Box service from
the exchange floor you got some significant traffic. Even though Mediaone
is clipped at 1500ms for downloading the broadcasting of that becomes a
problem when the data goes to all machines and the radio goes one machine
and the squawk box goes to another there are collisions galore.
That is why a switch is where I am headed or maybe a switch that has some
router capability and some ethernet cards with DMA capability.
Here is a list of my Best Pics on NICs
Feature Rich 3COM $35 - 45 manageable
<http://www.3com.com/products/nics/3c905c.html>
SMC about half the cost but is not manageable. $<20
<http://www.smc.com/eznet/data_sheets/EZNET_10_100.pdf>
Intel
<http://www.intel.com/network/products/pro100s_adapter.htm> $35 - 45
a top of the line card. Also offloads encryption from the CPU . This is
something that 3Com does as well in the server cards.
The SMC will do what you want. the others are really nice cards but may be
overkill. IT is nice though to mange everything from one location.
I think I would decide on the switch first before making a decision but I
am motivated by price to go with SMC.
For Prices see
<http://www.allstarshop.com/shop/Subsection.asp?dept%5Fid=86&sid=SHG5XEVJW4S
92HSE080205RWQ4XRCXB8>
SMC card prices you need to search <www.pricewatch.com> but incredibly
cheap considering the features.
>Date: Thu, 15 Mar 2001 17:08:16 -0500
>From: Simon Campbell <simtrader@xxxxxxxxxx>
>To: omega-list@xxxxxxxxxx
>Subject: [Off topic] Need help understanding DSL
>Message-Id: <4.2.0.58.20010315170119.009eda20@xxxxxxxxxxxxxxxxxx>
>Content-Type: text/plain; charset="us-ascii"; format=flowed
>
>
>Please excuse the novice-speak here:
>
>
>ADSL has just come to my neck of the woods and the ISP can provide a modem
>for either a network ethernet card, or a USB port. Since I have neither on
>my machine, I need to decide which of these cards I should purchase to
>stick in a PCI slot.
>
>
>The question is: which card should I buy - USB or Ethernet? (exact model
>suggestions appreciated!). I use a stand-alone PC and only want to use the
>phone at the same time as be on the internet.
>
>
>The ISP also is selling "ADSL Routers" - do I need one?!
>
>
>Thanks in advance,
>Simon.
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