Remote-Ac
cess Servers Pushed to Their Limits
On the other hand, U.S. Robotics' new Windows NT 4.0 RAS-based EdgeServer, lacking thorough diagnostics and management of multiple servers as a pooled remote access resource, performed merely adequately. Similarly, the MAX 4004 from Ascend Communications lacked management, performance and hardware flexibility. This is not to say that it doesn't have its place--it just couldn't keep pace with the changes that have been made by those vendors pulling out all the stops to succeed in the enterprise remote-access business.
3Com AccessBuilder 5000 Enterprise LAN/WAN Switch
 Big in every way,
AccessBuilder 5000 towers in form and function. Speed, flexible hardware and strong management have been forged into an impressive solution that we believe is the best large-scale switched-access solution for enterprise remote access.
Housed in a tall 17-slot chassis with redundant power supplies and enough lights to video your cousin's next wedding, the AB5000 begs to be tested. Not only did it support 96 asynchronous calls simultaneously, it offered the most hardware and software options of all products tested.
The AB5000 load-balances its traffic over multiple processors and data paths within the power-redundant, hot-swappable managed chassis. This setup effectively addresses chassis performance bottlenecks.
When we first tested all 96 ports, 3Com warned us that we might overutilize a single Ethernet segment (the version 3Com sent us for testing supported only T1, but PRI should be available by the time you read this). After picking ourselves up off the ground from laughing so hard--after all,
we've seen a single Ethernet segment handle more than 200 ports without any ill effects--we promised to watch for excessive collisions and utilization levels.
But the laugh was on us when we discovered that 3Com was right. At about 80 connections, throughput decreased steadily and b
ecame very poor by the time all 96 file transfers were pounding the Ethernet. Luckily, each AB5000 hub supports eight Ethernet segments or 10 Token-Ring segments. We segmented the traffic for the packet processors (our configuration supported four packet-processor remote-access server blades, each able to support 24 connections) each to a separate Ethernet segment.
Utilization on the Ethernet segment measured 75 percent with about a 49 percent collision rate prior to the segmentation, and a cool 25 percent utilization and 10 percent collision after segmentation. After wiping the smug look off our faces, we smiled to see our throughput level off at a rapid pace no matter the call load.
We previously had occasion to use
3Com's 16-bit Windows management application, Transcend AccessBuilder Manager, and thought it would be fine for configuration in this instance. And aside from its usual slight inconsistency in terms of display, it was; it didn't crash, which was a problem we encountered with earlier versions of the management app. Configuration options for the management application had all been moved from the telnet character interface to the GUI, and the diagnostics were accurate but a little funky to use. For example, instead of remaining on the highlighted selected entry of interest, the cursor kept returning to the first instance in a table upon every screen refresh. This meant we had to scroll down to the target statistic between polls.
Before we went any further, 3Com offered us its Access Watch browser-enabled diagnostic and capacity-planning management tool. This NT server-based tool combines usage information from multiple servers into a single view.
We first had to install the Simple Network Management Pro
tocol (SNMP) trap handler, AccessBuilder Trap Manager, which receives traps from any 3Com remote-access server and enters them in the NT Event Viewer log. Once the trap handler is installed, Access Watch runs on Netscape Communications Corp.'s FastTrak server on the same server as the trap ha
ndler. Each AccessBuilder remote-access server needs to be added to the server, but a nice touch is that these servers can be added in groups, so statistics for entire groups of servers can be accessed, rather than having to combine statistics manually from multiple servers.
Access Watch does not provide configuration or real-time statistics, but it does offer looks at session information, including termination reasons and top 10 users. It also gave us a view of statistics, alerts and events. The detail on the event log provided a simple drill down to the specific meanings indicated by a specific alert.
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