Optimizing Network Performance
Striking a Balance between Cost and Performance

Every day technology moves forward. New business applications are released (like Inventor 10, etc.) and those applications place a growing demand on communications for your company. 10 M/Bit Ethernet, whether over 10BaseT or Cat2 Coax (tell me you are not using a Coax Ethernet network with the T’s and BNC connectors) simply does not provide the bandwidth needed to move data up and down the pipe! With the advent of faster machines, One Hundred Megabit Ethernet is dragging down performance too. So what are the options? Do you need to upgrade the entire infrastructure, or are there things you can do to optimize your network without replacing everything from your backbone to your NIC’s (network interface cards)? The answer to that question is, it depends; let me explain.

How Does Ethernet Work?
To explain the network requirements for increasing performance, you need to understand how Ethernet works. Hopefully all of you out there are using Ethernet in some variety, whether hardwired or wireless.  If not, you should really pay attention to this article and dump Token Ring, Arcnet or what ever arcane protocol you are using. Anyway, back to how Ethernet works. Ethernet functions using CSMA/CD, or Carrier Sense Multiple Access / Collision Detection. What that is in simple terms is this. If there is a signal present and the computer has something to send, it does so, along with every other computer on the network. It is kind of like being in a classroom and everyone asking the instructor a question at the same time. If one tries, the communication goes through, but everyone on the network has to listen to see if the message is for them. If two or more people try to talk at the same time, a collision is detected. At that point, a random algorithm takes over and delays the communications by a random time frame on all stations and then they try to talk again. That is why inherently Ethernet transmissions have collisions and overhead that eats up bandwidth.

Is Speed an Issue?
Speed can be an issue. As the network speed increases, the timing gets tighter and thus in a standard NIC and Hub network, you get more and more collisions. Can that be cured or, at least, improved? Yes, and now it can be done with little physical or financial impact. First, we will be basing the suggestions on your having a CAT5 or better infrastructure, and for this scenario you have 10/100 Megabit Ethernet Cards. The solution is really quite simple. You replace your hubs with switches. The theory behind switches is that they learn what devices are located on which ports and very simply, they only allow traffic to a particular station or server to be directed there, and not to all stations. Simple really, but you will be surprised at the improvement you will see. Is there a level of machine population on your network at which you will see improved performance? Yes, and that is typically 20 to 30 stations, unless you have a server bank as well, but there are still a couple of things to consider. They are:

  1) Is your communication slow locally?
  2) Is your communication over a WAN or Wide Area Link Slow

Local communications will be improved by a switch, but WAN connections rarely are. Many of the devices, routers, etc. used in WAN’s use a 10 Megabit connection on the LAN site and connect to a communications line at 56/64 K or better on the WAN side. The WAN line is like a funnel. No matter how fast you push the data in the top of the funnel or how big the top of that funnel is, only so much can make it through the small end. If that is the weak link in your network, all the hardware you throw on the LAN will not achieve the results you seek, you will need to upgrade your wide area link. Maybe you will need a T1 instead of that DSL line. Also while we are talking about DSL, make sure if you are using DSL or Cable broadband you are using a solution they offer for business and not one for home users. All broadband offerings are not created equal!

But I Already Have Switches, What do I do?
For those of you who have switches, there is a decision that will need to be made at your company, but you will need to first know if:
  1) there is a true need for the speed
  2) if your network wiring will support gigabit Ethernet
  3) Are you ready to upgrade everyone and everything or just by department
If you answered yes to the first two questions, you can upgrade the NIC’s in the servers and workstations to a 10/100/1000/10000 M/bit network card. These NIC’s will cost you a few extra bucks, but you can swap your existing ones without much impact for starters. Once the NIC’s have been replaced, you will need to replace the switches used by the workstations and servers your have upgraded with 10/100/1000/10000 M/Bit switches. Note that upgrading the server only or the workstations only, even if the switches are upgraded, will not provide you with much benefit.

What about Wireless?
Ok, I know, you want the convenience of wireless. For demanding communications, that is simply not going to work. You see, at 10 MB or even 54 MB, Wireless, with one user, is still slower than being tethered with a network cable, but what most people do not realize is that the available bandwidth for the individual WI-FI user decreases with each WI-FI user connected to the WAP (Wireless Access Point) and that WAP has a hard wired connection that is passing all communications back and forth from the hard wired network. As such, that WAP should definitely be connected to a switch and not a hub.

How can I get more information about Improving Network Performance?
You can get more information about this subject? The web provides a wealth of information. Check out the white papers offered by many of the main network vendors (3Com, Cisco, Netgear, Allied, Asante, etc.) and try to avoid those off the shelf solutions you can purchase at the local electronics superstore as they are geared to consumers and not businesses! You will know the brand names as they are not listed here and they are the ones you see at retail stores! Your IT department can help you too, just as your network specialists can. It will cost you some money or a lot of money, but 10/100 Ethernet has been out there since the days of the 200 MHz processor and quite frankly, at better than 15 times that speed, today’s processors have outstripped the ability of 10/100 Ethernet and a hub environment to provide speedy network connections; If you have questions or comments about this article, contact me (JohnBoline@hagerman.com).

 

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