[K12OSN] Linux Router

Joe O'Brien jobrien at meridian.wednet.edu
Fri May 28 18:36:20 UTC 2004

>How much are you getting a 4-port ethernet card for? You can get a
>decent enough 16-port unmanaged switch from Dell for about $100. You can
>find it elsewhere for significantly less. Going with that kind of
>hardware you open yourself up to a much larger chance of failure and
>more complicated problems when it does fail.

I've seen a few cards in the $10-$500 price range, but there are about 4
(Thanks to J. Theriault) now that are in the under $30 price range.  Of
course everything is based on the assumtion that I can find a linux
compatible 4port card in that price range that is reliable :)

>That said, I've thought about it too. It would be fun to just see it
>work, but running a firewall on it would be a nightmare trying to keep
>all the different NICs straight. I'd probably separate the firewall
>feature out to another box for manageability. Routing wouldn't be so
>bad, but I'd probably also consider swapping that out if I had the boxen
>to do it. Again for manageability purposes.

>Yes, it should be possible (much easier if the cards have built-in 
>switching ability such as the Asound AL500P 4 Ports Nway Swith + 
>10/100Mbps Dual Speed PCI Router card that are 19$US on pricewatch.com) 
>but it would be an administration nightmare.
>Imagine trying to diagnose a fault in a networks with a bunch of 
>machines packes with all those cards while trying to keep the network up :)
>J. Theriault
>administrator at maginetworks.com

I'm hearing a yes it is possible, but it would be a nightmare. What I'm
unsure of is the nightmare part.  

Configuration: I had to put the one I have here together in an afternoon
with parts I had lying around the office when the Cisco that was here died,
so I'm not overly concerned about this.  Once it's configured, you just
have to monitor and tweak it from time to time.  Running it as a switch
would be more planning on the config side.

Manageablilty: I find linux boxes very manageable, and I do need some
management capabilities in whatever solution I use.  
I also want to implement some form of vlan (or subnet) for each classroom
and some QoS would be nice at that level too in the MDF closet.  In the
classroom I would be fine with dumb switches, except some of the older
equipment in the classrooms do not like autosense.

Stability(Hardware):  A concern.  Finding quality 4port nics is one
concern.  By removing the harddrive and using a boot cd should improve
uptime, but hardware can always fail. Having a spare machine built and
using a floppy or network for the  site specific configs should minimize
downtime in case of failure.  Or use a usb pen drive. 

Stability(Software):  It's Linux, nuff said :-)  I know even linux crashes
from time to time and Software patches would be an issue somewhat, but the
fewer things installed, then fewer patches, fewer glitches.  Just reburn a
new cd every 6-12 months for updates, or use a usb pen drive. 

Diagnosis and Repair:  It's Linux, nuff said :-) I've had "firmware"
problems with some switches in the past that required I ship it back to the
vendor and pay them to fix it.  I've had ports die on hubs before.  Granted
I may have more things break on a Linux box, but at least it is fixable.

Performance:  My #1 concern.  In monitoring my linux router, I haven't seen
any major performance issues or any significant packet loss, even during
saturation of the connections.

I guess ever since the 4port cards came out I've been wondering about this.
 I look at a switch, much like I look at a Tivo, and I've almost finished
building that thanks to mythtv :-).

Thanks for your advice.

--joe o'brien


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