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Case study: schools break through the firewall

Case study: schools break through the firewall

Five years ago, the Imperial County Office of Education in California had a vision to put videoconferencing into every classroom in its 56 schools, but it wasn’t until last year that it solved a key problem: getting the video traffic to go through firewalls easily.

Now, with the installation of gear from Ridgeway Systems & Software, traffic can pass through the firewalls that protect the independent networks at each of the 17 school districts within the county.

This might prove to be the last major obstacle to video deployment, the district’s video­conferencing specialist, Alan Phillips, said. “We were close to being dead with IP video,” he said.

This was because of unforeseen problems getting firewalls properly configured to allow incoming video calls. Given the high cost of ISDN as an alternative, IP was the only economic­ally feasible answer.

One problem wasn’t technical; it had to do with jurisdiction. Phillips was in charge of a countywide teleconferencing project to be run over an evolving Gigabit Ethernet fiber ring that the schools lease from the local water district. Each school district is connected to the ring, and each district’s network is run autonomously. So Phillips had no authority to choose a standard firewall between each district and the common WAN or to order that the various installed firewalls be set to accept incoming video calls.

Initiating a videoconference requires the calling machine to connect with the receiving machine. But if firewalls are in between, they can cause problems in two ways. The firewall protecting the machine being called will block the initial incoming message as unsolicited traffic. Both firewalls might be translating private LAN IP addresses into public IP addresses. That can create discrepancies between packets’ internal and header addresses, causing them to be dropped.

Even in trials with Polycom ViewStation FX videoconferencing units in which Phillips controlled the firewalls, configuring the firewalls was tricky.

Although he set his Cisco Systems PIX firewalls to allow the video traffic in and out, performance glitches arose. Sometimes, just audio would get through, but no video.

He tried installing an Accord videoconferencing bridge to traverse the firewall but that required a more complicated dialing plan that end users could not adapt to.

When Phillips heard about Ridgeway, he set up a demonstration of its IPFreedom software between a PC in his office that was equipped with Polycom’s ViaVideo gear and a PC at Ridgeway’s office. He downloaded a Ridgeway client to his PC.

In minutes he set up a videoconference with the Ridgeway representative, Phillips said.

Ridgeway gear consists of client software called IPFreedom Client, that runs on PCs or servers behind firewalls, and IPFreedom Server, that oversees all the clients in a user’s network.

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