How does network traffic travel across a simple LAN?

aplnub

I have 8 cameras setup to perform video surveillance with Security Spy powering the camera's. 4 of the camera's are high resolution 2 mega-pixel video cameras. Between the 8 cameras I have a lot of bandwidth tied up across my network.



I am curious to know how network traffic travels across the network in order to keep the bandwidth from dragging everything else down with it. For instance, currently, security spy runs on my 24" iMac. All the camera's go to a central gigabit switch along with every other computer I have.



My iMac has an assigned IP address (just like the cameras) on a DHCP network with a Linksys router connected to my cable modem. Nothing plugs into the router except for one 24 port gigabit switch. Everything is currently run directly into the gigabit switch.



If I had an intermediate switch that tied the camera?s and my iMac into, and then tied that switch into my central switch, would that cut down on the amount of traffic the main gigabit switch would handle? Or does the information get bounced around on all switches on the network?



Thanks in advance as I have no idea how network traffic is handled on a simple LAN setup like this.







FYI for those who are interested in this stuff: I had to purchase a Mac Pro yesterday to run Security Spy on it?s own because my iMac is totally max?d out on CPU usage.

hardeeharhar

Your setup sounds like a disaster waiting to happen -- you have your security system essentially accessible to the internet because you have no firewall.



And think about how a network would be designed: the signals wouldn't be distributed across all open ports as that would be wasteful and involve massive computation to parse the signals.



To answer your main question, yes, if you put all of your cameras and the computer running your Security software on a switch, then your computer network on a central switch would be faster. This is because the computer running the software would only connect to the central switch when it is looking for an internet connection...

dfiler

Sorry, I have to disagree with pretty much everything in the above post.



If your switches are rated as wire-speed, your setup shouldn't pose a problem. Wire-speed means that all ports can run full speed in both directions simultaneously. Traffic on one port has no affect on the performance through other ports. Many consumer grade switches aren't wire speed but they are damn close. I wouldn't worry about it at all. Most switches don't even break a sweat with the type of usage you're describing.



Generally it is preferable to flatten the network topology, removing all but the most necessary switches and routers. However your setup shouldn't pose a problem traffic wise. The gigabit connection to your mac will be the bottleneck no matter what switch it is plugged into.



Since all of your gear is behind your router, it is your form of security. Unless you're a high profile site or have very critical data, it probably isn't worth doing anything else for security.

aplnub

All switches are net gear. The 24 port switches (we have two running) are the Net Gear Pro Safe models.



The problem that led to the purchase of the MacPro was CPU power. I just didn't have the CPU power on my 24" iMac to run all that video streaming into Security Spy while still being able to work in VMWare, adobe, and power the Security Spy web server.



I just moved SS over to the MacPro and everything is a lot better. The web access to the SS web server is running better and the SS widgets are doing fine. This is with the computer going through two intermediate switches before hitting the main switch. I imagine it will only get better now that I know how the traffic flows.



Thanks!