Why does a router require so much processing power?

[Philippine Mango]

Why does a router require so much processing power? At first when I saw the description for smoothwall etc. and the requirements, I thought that the requirements for a PIII were a bit extreme and the need for 256MB of ram but then I looked up the specifications for my router and saw that it hosts a 200MHZ processor and thats a LOW END router! (4port) :shocked: These requirements are for hosting higher functions such as VPN etc. Can anyone explain to me if you're in 1997 and you've got a sizeable 10/100 network, how would you support the same number of machines? They didn't have PIIIs back or other processors of that speed (but close) so how would they handle all of that work load.

've always wondered about things such as this since it seems everyonce in a while a technology will come out that has demands that far exceeed the technologies of the time yet are somehow still viable?

HDTV anyone? They had the HD monitors in 1999 yet I can't think of a single computer that could process HD content in real time, so how would it be possible to view it? Same concept, so I'm wondering, how would you have a router with those kinds of functions without seemingly the technology available?


Does anyone get what I'm saying? It seems kind of ODD but I feel that it makes sense and doesn't make sense at the same time. :frown:

 

[Nothinman]

Generally it doesn't, especialy if you don't plan on using any encryption. I could see the higher-end CPUs and memory being desirable for the web management stuff, but for just normal routing and NAT it doesn't take much at all.

Back in 1997 VPNs and encrypted WiFi weren't all the rage, most routers just routed and Cisco sold (actually I don't know when they started selling them) VPN concentrators to handle the VPN stuff.

 

[spidey07]

As the packet per second forwarding rates (routing) increase, the processing power increases right along with it. Back in the day even a high end hardware router pushing 45 Mbs was extremely expensive.

It takes processing power to take the packet, inspect it, applie any filters, etc and then put it on the outoing interface.

So in essence bandwidth is doubling around every two years. Right along with processing power? Coicencidence? Nope.

-edit-
And in 1997 the Bay Network BCN and Cisco 7500 routers were how you ran 10/100 networks. These were large, modular routers with each slot housing an interfaces processor and a route processor. The route processor had one or two CPUs, advanced for their time and some memory. Around year 2000 these functions were developed in hardware (ASICs). Today all the functions are done in hardware, with specialty functions being handled by the processor.

Encryption is notoriously processor intensive, so it is normally handled in hardware.