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Bridge Ethernets Over T1?
michael_cain asks: "I have to take a series of demos 'on the road' occasionally and have to have a data connection back to the home lab. In many cases this takes the form of a T1. In order to terminate that at both ends, I currently have to have a CSU/DSU and baby router at each end. I would like to simplify this arrangement; does anyone know of a pair of small boxes that would let me use a T1 as a simple Ethernet bridge (well, a learning bridge would be nice)? Just plug the T1 into one side of each, a 10BaseT or 100BaseT into the other side of each, and relay Ethernet frames back and forth?"
Sorry to reply to my own post, but as a second thought, try FreeSCO which is a free linux based router - it probably isn't quite as compact as you're looking for, but runs nicely on modest hardware, and couldn't be easier to set up. A couple of low end pentiums with a pair of net cards in slimline cases would probably do the job nicely.
Deep in the bowels of the Ethernet spec is a maximum propogation delay between hosts. This limits the distance between hosts. I don't recall the exact number of milliseconds, but I think you're limited to about a campus size. Perhaps a smart bridge could get around this by buffering. If you just want to reduce the amount of equipment you lug around, try finding a high speed serial port that will handle T1 for one of your computers and run PPP, that will eliminate the seperate router or bridge. (Assumes an OS that will route IP.) We use an SBus card from Sun to do this, and I think we've considered PCI versions.
A baby router with an integrated CSU/DSU is probably what you want. Then you have the option of routing IP or bridging traffic. (depending on the router you buy) It could also act as a DHCP server, NAT box, etc which might be useful.
A cisco 1720 with integrated CSU/DSU is about $2200 list price.
Or, buy a synchronous PCI card with integrated CSU/DSU (~$600) and install it in your demo server.
If you're just using a laptop, perhaps one of the docking stations with a PCI slot would be workable. Dell has these.
This would require drivers under your OS, etc so it would probably be more of a hassle than just integrating the CSU/DSU into the router. Also with the router you can hook anything to it, and you don't have to worry about having drivers, etc for your OS.