hat this saves them money by renting less office space. More traveling professionals than before are getting access to the network on the road."
For this reason, many network managers are turning to remote-access servers to improve network connectivity for those who work outside office walls. With a remote-access server, you can dial directly into the network over dial-up, ISDN, or leased lines. The server acts as a traffic cop, directing incoming messages to resources on the LAN. This way, telecommuters don't have to dedicate a system in the home office for remote-control access of a PC as long as their files are somewhere on the dial-up LAN. Also, the routers can act as sentinels for network administrators
to manage protocols and security for remote access to the network.
Networking systems, particularly those including remote access, rely on complex--and sometimes fragile--interdependencies among their numerous component parts. Not only must each component of a remote-access system work well by itself, it must also integrate with the other components to provide a cohesive whole that works from end to end. Your remote-network calls must go through a gauntlet of modems, telephone lines, gateways, and the servers themselves before they reach the LAN. Everything has to click in a remote-access solution. Otherwise, remote users will become isolated islands in your firm's data stream.
In this hardware roundup, we tested five eight-port remote-access servers. They range in price from $1095 to $4745 and--relative to other remote-access servers on the market--are low-end solutions because they are limited to eight or 10 ports. If only this number of remote users will access your LAN concurrently, they'll
do the job. Otherwise, you'll need a more expensive 16-port (or greater) server, which most of the vendors offer. The servers enhance file transfer speeds, help users access company databases, and run enterprise applications that reside on the central LAN.
To be included for testing (see the article "Test Specs"), a remote-access server had to have eight simultaneous connections; have support for Novell NetWare 4.x (we tested with a NetWare server), Windows NT 3.51, IPX/SPX, and TCP/IP; and provide asynchronous data transfer rates of at least 115.2 Kbps. We based our evaluation mostly on performance because fast network access is a concern for remote-access users. However, for systems administrators, usability and features are important. Therefore, we weighed those two components almost as high as performance.
The Remote Possibilities
The five servers--3Com's AccessBuilder 4000, Digi International's AccelePort 8em, Emulex's ConnectPlus Pro, SBE's netXpand Central, and
Shiva's LanRover/E--offer different architectures and price/performance levels. The routers use serial-port connections for external modems or have Type II or Type III slots for PC Card modems.
The servers
all come with
remote-access management software, and they have such security features as encrypted password protection, the Password Authentication Protocol (PAP), and the Challenge Handshake Authentication Protocol (CHAP). The major reason there are so many checks and challenges is security. Once you are authenticated by the router itself, you are then given the opportunity to attempt a network log-in.
Emulex's ConnectPlus Pro and SBE's netXpand Central are PC Card-based remote-access servers. The ConnectPlus Pro has four Type III PC Card slots, where users can stack eight Type II modems. There are also two WAN ports and one V.24 asynchronous port. The server has a 25-MHz Motorola MC68360 processor with a daughtercard slot for upgrades. The netXpand Central has eight Typ
e II PC Card slots and two serial WAN ports. These servers obviously don't come with modems, but you can buy eight 28.8-Kbps modems for about $160 each, for an additional cost of $1280.
Digi International's AccelePort 8em is the lowest-cost remote-access server we tested. It consists of an ISA board that you install inside your network server with eight serial ports for external modems. The server uses an on-board processor to handle serial I/O interrupts, character processing, and data transfers.
Shiva's LanRover/E and the AccessBuilder 4000 use external modems for remote users to attach to the LAN. These are higher-cost solutions, but their high performance makes them well worth the price.
To test the remote-access servers (see Test Specs on page 107), we bombarded the routers with remote-access requests from eight users over regular analog telephone lines. The servers must direct the calls to applications, data, and personal file directories--something a telecommuter would do during a
regular workday. For the best remote-access performance, we recommend ISDN- or T1-line connections, but as with the faster servers, the wider bandwidth will shrink your wallet.
Contributors
Jim Kane, Project Manager/NSTL
Dorothy Hudson, Project Manager/NSTL
John McDonough, Technical Writer/NSTL
Maggi Bender, Technical Analyst/NSTL
Susan Colwell, Technical Editor/BYTE
illustration_link (54 Kbytes)
5 Reliable Servers for Remote Access
