Base adopts Gigabit Ethernet

Base adopts Gigabit Ethernet

Army training center replaces ATM network to lower costs, boost performance

By William Jackson

GCN Staff

Fort Polk, La., home of the Army's Joint Readiness Training Center, last July retired 21 asynchronous transfer mode switches and their 4-year-old backbone, changing to a Gigabit Ethernet network.

'The backbone had become congested and no longer supported the amount of traffic we were putting through it,' said Wilford Parker, Fort Polk's network manager.

Parker had the option of upgrading the 155-Mbps OC-3 ATM infrastructure or replacing it with a new technology. Gigabit Ethernet won out for both cost and performance, Parker said.

'Gigabit is inexpensive compared to ATM,' he said. 'It is a continuation of Ethernet. ATM is a whole different technology.'

The center supports training for joint missions of the Army with other service branches. Its facilities include village mockups that soldiers can practice assaulting, defending or policing. Training units rotate through Fort Polk for 30 to 60 days.

The center installed the ATM network in 1995 under the Army's Common User Interface Transport Network program, which specified dual ATM switches at the network core, linked over an OC-3 Synchronous Optical Network to routers. Fort Polk used the Centillion 100 switch from Nortel Networks Corp. of Brampton, Ontario.

For Fort Polk's new Gigabit Ethernet, Foundry Network's BigIron Layer 3 routers in the main and area distribution nodes support FastIron II switches in wiring closets.

Changing demand

The Army got its money's worth out of the ATM LAN, Parker said, but demand outstripped capacity when the center automated the tracking of thousands of troops and added more of the base's 200-plus buildings to the network.

'We feel it served us well,' Parker said. 'We absolutely think we made the correct decision in 1995 with ATM, and in the past year, Gigabit Ethernet was the right decision.'

The present network is built on switches and routers from Foundry Networks Inc. of Sunnyvale, Calif. At the core, in the main node and in the 19 area distribution nodes are BigIron 8000 and 4000 Layer 3 switching routers. They support 64 and 32 ports, respectively, for nonblocking, wire-speed Gigabit Ethernet.

The BigIron switching routers connect in wiring closets to FastIron II switches, which support up to 72 ports of 10/100-Mbps Ethernet. Some smaller buildings use FastIron Workgroup switches with 24 10/100 ports.

Connections from the area distribution nodes to the buildings are Ethernet, Fast Ethernet and Gigabit Ethernet, depending on user needs, Parker said.

'Our plan is to eventually get gigabit down to all the buildings,' he said. That means planning for one of the Army's first installations of gigabit copper, probably early next year.

The standard desktop pipe is Fast Ethernet, although there are some 10-Mbps connections, both switched and shared.

At the main node is the base's T1 connection to the Internet through MilNet. A CacheFlow server from CacheFlow Inc., also of Sunnyvale, stores frequently used Web and intranet pages. Foundry Networks' ServerIron Layer 4 switch redirects traffic to the CacheFlow server when pages are requested, improving response time and decreasing bandwidth demands on the Internet connection, Parker said.

'I don't see us outgrowing' the gigabit infrastructure anytime soon, Polk said. Up to eight Gigabit Ethernet lines can be trunked to increase bandwidth if needed.

He added that 10-Gbps Ethernet is 'right around the corner, and the basic equipment we have here is ready for that.'


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