By Art Reisman
Editor’s note: This article was adapted from our answer to a NetEqualizer pre-sale question asked by an ISP that was concerned with its upgrade path. We realized the answer was useful in a broader sense and decided to post it here.
Any router, bandwidth controller, or firewall that is based on Intel architecture and buses will never be able to go faster than about about 7 gigabits sustained. (This includes our NE4000 bandwidth controller. While the NE4000 can actually reach speeds close to 10 gigabits, we rate our equipment for five gigabits because we don’t like quoting best-case numbers to our customers.) The limiting factor in Intel architecture is that to expand beyond 10-gigabit speeds you cannot be running with a central clock. Therefore, with a central clock controlling the show, it is practically impossible to move data around much faster than 10 gigabits.
The alternative is to use a specialized asynchronous design, which is what faster switches and hardware do. They have no clock or centralized multiprocessor/bus. However, the price point for such hardware quickly jumps to 5-10 times the Intel architecture because it must be custom designed. It is also quite limited in function once released.
Obviously, vendors can stack a bunch of 10-gig fiber bandwidth controllers behind a switch and call it something faster, but this is no different from dividing up your network paths and using multiple bandwidth controllers yourself. So, be careful when assessing the claims of other manufacturers in this space.
Considering these limitations, many cable operators here in the US have embraced the 10-gigabit barrier. At some point you must divide and conquer using multiple 10-gig fiber links and multiple NE4000 type boxes, which we believe is really the only viable plan — that is if you want any sort of sophistication in your bandwidth controller.
While there are some that will keep requesting giant centralized boxes, and paying a premium for them (it’s in their blood to think single box, central location), when you think about the Internet, it only works because it is made of many independent paths. There is no centralized location by design. However, as you approach 10-gigabit speeds in your organization, it might be time to stop thinking “single box.”
I went through this same learning curve as a system architect at AT&T Bell Labs back in the 1990s. The sales team was constantly worried about how many telephone ports we could support in one box because that is what operators were asking for. It shot the price per port through the roof with some of our designs. So, in our present case, we (NetEqualizer) decided not to get into that game because we believe that price per megabit of shaping will likely win out in the end.
Art Reisman is currently CTO and co-founder of APconnections, creator of the NetEqualizer. He has worked at several start-up companies over the years and has invented and brought several technology products to market, both on his own and with the backing of larger corporations. This includes tools for the automotive industry.
December 11, 2010 at 3:43 PM
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