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ISDN Switch Simulator on the Cheap?
smartmux wonders: "I've starting working on earning a CCNA certification, and part of the requirement for this cert and the 'professional' level cert is to know and understand how to install ISDN BRI circuits. Getting the Cisco router equipment to configure is easy and relatively cheap, but real ISDN lines or an off-the-shelf ISDN simulator is way too expensive. I'm not a *nix guy, so I thought I'd ask here -- is it possible to take an old PC, a couple of ISDN network cards, and an open-source PBX (like Asterick maybe) and make a simple ISDN switch to let my two routers talk?"
The CCNA exam has questions that are done on a simulator to simulate configuration or troubleshooting on a router. Most of the ISDN involved on the exam is theory, but he could be asked to show practical knowledge as well.
Who uses ISDN in a new installation anyway?
Companies that are directed to by their DoD customers. Companies doing point-to-point networking with existing facilities -- often to facilities in Europe.
Not every networking installation is a dot-com looking for Internet connectivity.
There are companies who rent time on systems that have all of the elements you might see on the test available. Here is only one of many examples http://www.thebryantadvantage.com/Rack%20Rentals.h tm/. Just do a google search for "rent time cisco ccna" and you'll have plenty of options appear. Probably a better use of time than setting up systems just for testing...but that's just my opinion.
Ever hear of a PRI T1?
ISDN is still highly used, to this day. In fact, our videoconferencing bridge allows all sorts of connectivity options - one of which we use is multiple "bonded" ISDN channels. So we can get 384k out of 6 channels...
Karnal
Well, you guessed right, Linux can do this!
A few links:
Linux 2.6 and mISDN HowTo
PBX4Linux
Have fun!
RFC1925
Who uses ISDN in a new installation anyway?
Me, for one. Not exactly a new installation, but I just converted a bunch of E1 lines from R2 signalling to ISDN. It took about 4 hours, 3 of which were experimenting and testing to make sure the signalling was correct, then about 10 minutes to switch over each E1 and monitor call reliability. Next week I have to bring a whole system over to SS7, and start to convert the far end from R2 to ISDN. It's a standard Cisco job.
I'm not a big fan of the Cisco certs, but Cisco does know what is out there in the market. If you are naive enough to think the world is only DSL lines then I don't want you anywhere near my kit. When I see someone has earned their certs coupled with some equivalent work experience, I know they aren't going to break a network when I show them something new (meaning old and well established). The world is full of X.25 circuits, SNA, appletalk, ISDN, SS7, IpSec tunnels, but you will never have a real job working on Cisco with a bad attitude and obvious bias not to learn what's needed.
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
They had (and theoretically still do have) an ISDN videoconferencing solution. However, they almost never used it. Then one day, the big boss (the actual owner of the 1,000-person international company) came and wanted to VC back to headquarters in Germany. Didn't work. The problem was the same as above: the LD service on the ISDN line was misconfiugred, and we could not make International calls. So not only was it a problem that prevented it from working, but it was a problem completely outside of my control. All I could do was wait for SBC to do their, ahem, magic...
He went ballistic. I was nearly terminated on the spot.
The great part of the story was that we knew he was coming over for a month before, and that there was a chance that he'd want to use it. I bugged the client a *number* of times to test the system all the way to Germany and make sure that it worked, but they didn't want to spend the time and money to do it. Due to some internal issues, they were way over on IT budget and didn't think it was important.
Fortunately, others (not the person I directly answered to, either) explained that I had tried to test the system, but was told not to. Within a year, there was a significant shakeup and a number of people were terminated, including the person I answered to. In fact, I've been part of that company at that location longer than anyone currently employed there! :)
The VC system is still in place, but it has not been used once since that event, over 3 years ago. However, every couple of months, I still test the system...
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