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  Port Switches: Dynamic Hubs Help Y ou Migrate Toward More Bandwidth By Joel Conover Do you find yourself reviewing your network plans for the new year and wondering how to cost-justify expensive network upgrades to the person who writes the checks? Maybe you won't have to panic. Network design is moving away from hierarchical routed networks that were built to segment and secure networks and is moving toward flatter, higher-speed switched networks. Yet, purchasing hundreds or thousands of switched Ethernet ports is no small expense, and many users may never see or need the added bandwidth. But several vendors are addressing the need for more segmentation without the high costs of a fully switche d network. The result is the port switch: a dynamic hub capable of supporting several independent segments of traffic. More than a stack of Ethernet hubs, the port switch balances the demand users put on the switch by letting them move to a less-utilized segment. Some normal switches perform this function automatically, moving users to the best switch segment, while others require a command issued to balance the traffic load between segments. The best of both worlds come together in a port switch, giving users more bandwidth without busting a hole in your pocketbook. We tested port switches from Hewlett-Packard Co., LANart Corp., 3Com Corp. and Transition Networks. Each switch provided different levels of functionality and manageability. In general, we found that port switches are at least half the price of a full-fledged switch, but offer enterprise management features you'd expect at a much higher price.
Hewlett-Packard Co. AdvanceStack Switching Hub-24R Bundle
The HP AdvanceStack is available in 12-port and 24-port flavors and is very expandable; it can stack up to eight units tall and the entire stack is managed by a single management module. The stack supports up to four segments, plus you can disconnect segments from the backplane, allowing for up to 32 independent segments in the stack. We tested the AdvanceStack Switch Hub-24R wit h a management module and a switching module installed. In this configuration, the AdvanceStack is capable of dynamically balancing traffic based on load. When using HP AdvanceStack Assistant for Windows (which comes bundled with the management module), balancing the load is a mouse click away. Alternatively, you can balance the load by logging into the switch via the console or telnet and perform the load balance through the ASCII interface. The switching module, which lets the HP AdvanceStack auto load-balance, also provides switched connectivity to the outside world by way of four external switch ports. This lets you connect uplinks or servers to dedicated pipes, and it results in higher overall throughput. Three of the four external switch ports are 10BASE-T. The fourth port is modular and accepts either a 10BASE-T or fiber connection. The switching module for the AdvanceStack is simple but functional, and it doesn't offer full-duplex capabilities. Managing the AdvanceStack is done via the HP Adv anceStack Assistant for Windows. Like the 3Com port switch, the HP product also provides security on a per-port Media Access Control (MAC) address level, including the ability to lock a port off if an intruder is detected, and send a trap to a management workstation. Se curity also is configured through the AdvanceStack Assistant. The AdvanceStack product supports four groups of the Remote Monitoring (RMON) specification; an 8-MB RAM upgrade is planned for the first quarter of this year, which will allow nine groups of RMON on all segments. The AdvanceStack supports redundant power for mission-critical applications.
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The networking people at Hewlett-Packard have cooked up an all-in-one solution that lets you expand your network as it grows. The HP AdvanceStack Switch Hub-24R starts out as
a 24-port unmanaged stackable hub. The hub has plenty of room for expansion, including two slots on the front and a larger slot in back for a switching module. We started with the base repeater, added the management module and then added the switching module. With all three, the AdvanceStack 24R has everything you need to do multisegment port switching in one box.
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by Anthony Frey Updated January 24, 1997 |
