Timothy
Parker Consulting Incorporated
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Many-port RAS solutions Time to move on to the largest of the remote access servers we'll consider in this column: the 16-port and over units. You could do the same job as these single-chassis multi-port servers simply by stacking several 16-port RAS units one on top of the other. If you've already got a 16-port unit, or you are not sure if you'll need more than 16 ports, this is a sensible way to go. But if you need more than 16 ports now or expect to grow beyond that number in a reasonably short time (two or three years, for example), then a multi-port chassis is the way to go. Bear in mind that we're still talking relatively small RAS units. There are remote access servers that offer hundreds of ports, and while some of the chassis servers we'll look at this column can do those numbers, when you get into that realm it's time to call in a RAS specialty company and ignore these smaller servers. Chassis-based RAS servers are, as the name implies, a case that allows multiple drawers or racks of ports to be added as the need arises. The best example to mention is the Computone Intelliserver Powerrack. Computone makes several different sized RAS units, but the Powerrack strikes me as one of the more talented and flexible servers when you need between 16 and 64 ports, the maximum currently allowed in this chassis. The Intelliserver Powerrack stands out for more than its expansion capabilities, solid design, and price-performance ratio. It is one of the few RAS units I've tested which has a lot of horsepower built into the RAS itself. The server is powered by a MIPS R3000 with 2MB RAM. This offloads the network to which the Intelliserver Powerrack is connected, as well as the host servers incoming callers connect to. Physically, the Intelliserver Powerrack units is not especially remarkable. It is a large dark-gray steel box with five slide-out panels on the front. The lowest panel in the chassis is the network connector and controller where the box's CPU sits. The network can be connected with BNC and AUI connectors (no RJ45 is supplied but a converter can be used). The four slide-in panel I tested offer 16 RJ45 ports and a single LED to show the card activity. Other panels are available from Computone with different connectors, or for special applications. Installing the Intelliserver Powerrack requires some room due to its relatively large size compared to standard 16-port RAS units. You also have to worry about providing adequate ventilation for the rear-mounted fan to cool the entire unit. In testing, the fan was one of the quietest I've run across, which allowed me to keep the Intelliserver Powerrack in a standard room rack instead of hidden in an equipment closet. To configure the Intelliserver Powerrack you connect either a dumb terminal or a cable to a terminal window on either a UNIX or Windows system. Configuration is done by answering a series of questions and using a menu-driven interface. Configuring is a slow job, but is foolproof and simple. For UNIX users, the Intelliserver Powerrack is particularly attractive as each port on the RAS looks like a standard tty port. This makes it easy to configure the server with any UNIX system. Windows NT is supported, of course, but requires drivers for the COM ports. Why am I focussing on the Intelliserver Powerrack? It's one of the few RAS units that provides expansion to 64 ports and still allows each port to run at speeds up to 921.6kbps. That supports really fast serial lines! In my lab I was unable to bring the Intelliserver Powerrack to a slowdown, even bombarding 32 ports with simulated 640kbps traffic (the equivalent of four dual-B channel ISDN lines bonded together on each port). The onboard CPU kept right up. The only limiting factor in performance is the network (a 100Mbps Ethernet network is highly recommended for high traffic loads). The The Intelliserver Powerrack supports most protocols you could wish for. For dial-in sessions the Intelliserver Powerrack supports PPP, SLIP, RIP, RADIUS, and IPCP. For network management there's SNMP. The security components of the Intelliserver Powerrack software are excellent, offering flexibility for limiting access and specific hosts that can be reached by each login. Intelliserver Powerrack is easy to install, configure, and support, and runs like mad. It's my favorite for the 16-64 port region, despite its lack of a fancy Windows GUI. Maybe that's an advantage. If you need more speed than the Intelliserver Powerrack can handle, such as for a T1 or T3 line, then you need a different approach altogether. One unit that can handle things like this is the Osicom IQX-200. The IQX-200 can be configured with standard remote access ports (from 8 to 168!) but the real strength of the unit is its flexibility for other incoming and outgoing lines. The IQX-200 is really a small tower PC with the resident CPU and RAM used to offload the network and host servers. The back panel of the computer is where slots for the ports reside. My test unit had three sets of T1 connector cards, a standard RJ-25 Ethernet card, a slot with an 8MB flashRAM PC Card, and a single DB9 connector. The IQX-200 can be configured with ISDN and synchronous modem cards or any combination. It also supports FDDI cards (both single and dual) which makes it unique in affordable RAS units. If you're looking for a unit that can handle any of the fast telephone setups (ISDN or T1) as well as the odd regular comm port, this is a unit that's capable. |
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