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Can You Purchase Switch Hardware Without an OS?
dhahn asks: "I have a project where I'm building a large Linux router (about 40 ports or so). At this point, my only hardware solution is to purchase a box with lots of PCI-ish slots and fill them multi-port ethernet cards. I've looked into currently available solutions and haven't found anything that gives me the control I want. Does anyone know of where I could purchase a 'naked switch?' I just want the switch hardware with enough guts to allow me to customize a Linux OS and load it up." If anyone else has been in this situation, what did you do?
Why not use any managable switch, configure each port into its own vlan, hook up the Linux box to a trunk port and use Linux's vlan support, like anyone else does?
You want to build a router, but you are looking for switch hardware.
You are asking for independent ports. If you need to route through each port seperately and not 'switch' data between ports but 'route' it among them then you need router hardware not switch.
See the thing with switches is that chips are available with 4 ports or 8 ports and it automatically switches data in ASIC between ports. Usually these chips cannot be interfaced to a microcontroller and almost never have PCI interfaces.
You do need individual ports, not a switched collection of ports. So you need something with 7 PCI ports (7x4=28). There are plenty of 4-port PCI cards out there, but there must be 8-port cards too. I have seen plenty of 6-port motherboards. You will have to use PCI extension devices to get to 7 or 8 ports unless you find those 4+ port ethernet cards. Do keep in mind you cannot switch between all ports at wire speed. You'll need faster busses and powerful processors. At this point you're looking at highly specialized hardware like cisco juniper etc.
It is inefficient to route between that many ports on a single CPU. Its better to cascade entire routers if your design allows it or add switches to routers with fewer ports. Unless you are a telco providing high speed connections to ISPs or a central location breaking the bandwidth for many branches, I dont see why anyone will need a router with 30 ports. In any application when you need more processing power, you'd divide the algorithm and use multiple CPUs or multiple computers. In this case you can almost definitely use cascaded routers if you need that many ports in the first place.
I have a Cisco 4700M router with 12 10-mbit ethernet ports. Never needed more than 3.
"Give orange me give eat orange me eat orange give me eat orange give me you." -Nim Chimpsky
Depending on how adventurous you feel about getting linux running on strange hardware, you could buy a used cisco or foundry L2/L3 box for cheap. I know there are a lot of linux projects at cisco, there must be something you can google about how they went about compiling for the platform. The CPUs inside will be something non-mainstream, i.e. not a pentium, but chances are there is a linux distro for it. It shouldn't be that hard to find some archived info on how to bootstrap a linux distro onto one of those boxes.
Used cisco 3500s or 2950s with 24 or 48 ports are on the market for a few hundred (dollars or euros) each. Foundry workgroup switches are less than 100 euros right now. Cisco 7200s are just PCs inside, but their PCI buses are a different layout to allow hot swapping. Cisco Pix 515s are just commodity 1U intel pc motherboards, cisco didn't even bother doing a redesign to remove the superfluous connectors.
If you have enough money for a PCI-ish box and many quad ethernet NICs, then you probably could afford a used Juniper M5. It already runs BSD, and pretty much looks like standard PC hardware inside. A used M5 without any interface cards should be had for less than a new PC, its the interface cards that will cost you dearly.
If you follow my advice, then with any luck you will document everything you did along the way, and release a linux distro for some otherwise proprietary hardware. I'd like to see a cisco 2950 turned into a linux box with all kinds of extra linuxey features. What I'd love to see is openBSD's pf on a switch, so I could set per port ACLs and bandwidth shaping.
the AC
Hemos is like...sci-fi fans;he thinks technology is cool, but he hasn't bothered to understand the science it's based on
I would suggest investing time looking into something such as Cisco 3750 series switches.
I can't speak for the original poster, but in our case we needed VLAN's to be unique per port. That is, VLAN 100 on port 1 should be switched to VLAN 105 on port 2, and VLAN 100 on port 2 should be switched to VLAN 200 on port 3 and 4, and so on. Trivially easy to do in Linux, not so with a 3750. You can do it with VLAN mapping, but you can also buy quite a server for the price of a 3750 and the Advanced IP Services image. Oh and the 3750 supports only 24 VRF-lites, whereas you can run quite a few more OpenVZ instances with routing on a Linux box.
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