You don't buy them from Cisco, Nortel, or Lucent -- you make them yourself. They're Linux-based routers running on old, retired PCs. All you need is a 486 PC or better, a few Ethernet cards, some free software, and presto! You have a router that supports RIP, OSPF, and even BGP.
The Linux Router Project offers the code that turns former doorstops into routers. It runs on a minimal version of Linux that fits on a single diskette. (Obviously, this isn't a Microsoft project!) The software is free, so assuming you already own a spare PC and a couple of Ethernet cards, you have a near-zero implementation cost. That's a big advantage -- the last time I looked, none of the big three router vendors was giving away its products.
Depending on your hardware platform, your expertise, and your courage, you can make a simple 10 Mbps Ethernet router using just a 486 PC with 12 MB of RAM and a pair of 10 Mbps NICs. With a little more horsepower and courage, you can have a 10/100 Mbps router/switch by using a 100 MHz Pentium or better with 16 MB of RAM and multiple 10/100 PCI NICs.
Want even more power? You can add RADIUS, PPP/Slip, and RAS by using a 100 MHz Pentium with 32 MB of RAM, 10/100 PCI NICs, and serial ports. Move up to a 166 MHz Pentium or better with 64 MB of RAM and 10/100 PCI NICs and you can add secondary DNS and a firewall to your routing switch. The number of NICs your PC can support and the horsepower in your CPU limit the total number of segments you can route.
The possibilities are staggering, and you certainly can't beat the price!
So what's the down side?
- Performance: If you need routing capabilities, have zero funds, are technically strong, and like to experiment, then a Linux-based router is likely a good solution. Otherwise, you are better off with an inexpensive router from one of the major vendors. Home-grown routers cannot offer performance that matches even an inexpensive dedicated router. If you run an enterprise network, you should definitely stick with the major router vendors, unless you plan to install the Linux-based router in a noncritical segment on your network.
- Support: Don't count on a 24/7 support center. In fact, there isn't much of any support available; you must be prepared to do most of the work yourself. However, there are FAQs that can help, and you can view archives of previous support messages.
- Reliability: PCs, especially older ones, rarely have multiple hard drives and backup power supplies, so they offer less redundancy and reliability, which in turn could lead to more downtime. If you're using Linux-based routers, it's prudent to keep an extra router or two on hand for emergency swap-outs.
Clearly, Linux-based routers are not suitable for use in enterprise networks, but they might find a place in less critical situations where a cheap routing solution is needed. Smaller ISPs, branch offices, or even some home-based networks might make a nice spot for a minirouter.