POP Goes the Internet

The Army overcame significant technical challenges to provide Internet service over the narrow-bandwidth tactical command and control networks supporting the Bosnian peace-keeping mission.

The digital field switches and tactical satellites used by the Army's Tactical Packet Network (TPN) were designed to handle classified data and did not easily lend themselves to providing unclassified Internet connectivity.

The 5th Signal Command first started developing a system to send unclassified data over TPN two years ago, when the command supported U.S. forces engaged in a relief mission to Rwanda. TPN gear has a 56 kilobit/sec unclassified channel next to the secret network, but the command had to devise a way to separate unclassified and classified data.

The solution was to use a Motorola Network Encryption System (NES) and firewalled routers that separate the traffic. The Motorola gear was originally designed to send classified data over an unclassified network. "We're essentially using NES backwards," said Bruce Funk, 5th Signal's civilian network manager for the project. "We're using it to send unclassified data over a classified network."

The command developed a package around the Motorola gear to provide unclassified connectivity to users in the field, and it developed the Deployable Automated Support Host (DASH) van, currently fielded at Kaposvar, Hungary, to support data users there.

The DASH van allows users from the 1st Personnel Command to tap into stateside databases. The users employ tactical modems hooked up through an NES, a series of Cisco Systems Inc. routers and an AT&T 3B2 minicomputer installed in the van.

However, the DASH van, mounted on a 5-ton truck, did not meet the requirements for an easily deployable system, Funk said. So the command started working on what has become the standard field data package for V Corps: the point of presence (POP) router.

The standard POP package includes an NES, a Cisco 4000 router with eight serial and one Ethernet ports, a Cisco 515 16-port terminal server and a Hewlett-Packard Co. 900/750 workstation that acts as an electronic-mail host.

This POP package also comes with 16 tactical terminal adapter modems so users can hook their PCs into the tactical telephone system. Once installed at the forward operating bases (FOBs) in Bosnia, users can run field wire up to two miles to hook their PCs into the system.

5th Signal also developed a "mini-POP" for areas with a smaller group of data users, such as Zagreb and Sarajevo. This package consists of a Cisco 2501 router with one Ethernet port, two serial ports and Cisco 516 term servers.

The POP router does have its limitations, Funk said. The majority of users connect to the system through a Mobile Subscriber Equipment small extension node switch, which provides only 16 kilobit/sec of unclassified bandwidth. "Interactive response can vary from very good to frustratingly slow, due to a combination of encryption/decryption delay, 16 kilobit/sec links and multiple hops," Funk said.

Despite these limitations, users in the field have embraced the POP package, with the 22nd Signal Command installing POP packages to provide connectivity to Combat Service Support users at 17 FOBs wanting to tap into the Standard Army Management Information System (Stamis). Users at the other seven FOBs will string field wire to the nearest POP.

Maj. Brian Hamilton, engineering integration officer for 22nd Signal, said dial-up capability was an absolute essential for Stamis users "because Stamis will only work through a serial port. It won't work on a LAN because it was designed for office users who could just dial into a database."

Hamilton added that providing connectivity to logistics systems from the FOBs was key to meeting the "move data, not people" mandate of V Corps commanders. "If you don't have the pipes for the logistics systems, it means you have to take a disk out of the PC, get in a Humvee, form a convoy [a minimum of four vehicles is required] and drive down the road.... This system keeps the troops off the road."

Funk said Internet connections provided by the POP routers also make a big difference for troops and family morale. "This means troops can now communicate with family members who have Internet accounts or accounts on systems like CompuServe or America Online," he said.

Lt. Gen. Otto Guenther, the Army's director of information systems for command, control, computers and communications, endorses the use of these tactical links for morale purposes but cautions, "People have to be careful. When you realize how thin the bandwidth is, it would not take a lot of traffic to clog up one of those circuits."