Sizing Up NT-RAS Cards

FRAMINGHAM (03/27/2000) - Last fall, we set out to determine whether multimodem adapter cards that plug into standard PC servers running Windows NT were a formidable, low-cost alternative to dedicated remote access concentrators for giving your remote users access to your corporate network. We found that they were.

Our next step was to take a hands-on look at five of these NT remote access cards, specifically, remote access server (RAS) cards that supported at least 23 V.90 analog client connections on the front end and a single Primary Rate Interface/T-1 connection to a PBX on the back end.

Brooktrout Technology's IRAS-24A was our hands-down winner because it scored the best across all our performance tests and offers an excellent set of management tools. This combination earned the IRAS-24A Network World's World Class Award.

Cards offered by Digi International, Eicon Technology and Interphase scored consistently well across our categories, and we think any of these products would serve up remote access in a corporate environment equally well. Ariel Corp. fell a bit behind the pack because it lacked polish in terms of its management tools, installation process and documentation. However, the Ariel card is one of the more scalable products in this comparison and costs half as much as its competitors.

While we tested these cards on NT 4.0, all the vendors are now offering driver support for Windows 2000 Server.

Speed tests

We placed a particularly high value, a 40 percent weight, on the performance of these cards because getting data to and from your remote users as quickly as possible is what a RAS is supposed to do.

We tested how each of these cards downloaded and uploaded files of varying types and sizes.

In the download speed tests, Brooktrout's IRAS-24A at 72K-bps average throughput was 5K-bps faster than the next-fastest card. In a near tie for second place were Digi's DataFire RAS PT1, Interphase's Entia 5536 and Ariel's RS2000. All averaged around 66K-bps. Eicon's Diva Server PRI was slowest in the download round of testing, trailing the group by 8K-bps.

In the upload speed tests -- which are consistently higher than downloads because the data processing is spread over all clients, as opposed to being handled solely on the server card -- Brooktrout's IRAS-24A and Digi's DataFire RAS PT1 stood within 1K-bps of each other at 86K-bps and 85K-bps, respectively.

Eicon's Diva Server PRI and Interphase's Entia 5536 occupied the middle ground at 80K-bps and 78K-bps, respectively. Ariel's RS2000 brought up the rear at 72K-bps.

Some of the units had trouble maintaining performance speeds as we added clients. This condition, in addition to the performance measurement, also plays into how scalable these products can be in an enterprise network.

Eicon's Diva Server PRI download throughput dipped 13K-bps as we increased the number of clients from one to 23 during the download testing. Eicon's performance remained constant while we added clients during the upload performance tests.

Conversely, Ariel's RS2000 download measurements were consistent, but its performance lost momentum on the upload side. Overall, there was a 10K-bps performance difference with the RS2000 when we moved from a single user to 23 users. Digi's DataFire RAS PT1 also had a consistent upload, but lost 6K-bps between the single-user and the 23-user passes on the download side.

Brooktrout's IRAS-24A and Interphase's Entia 5536 stood constant as we added users, losing only 1K-bps or 2K-bps of their performance up to the 23-client level.

Almost as important as speeds and feeds are the tools that each vendor provides for configuring and managing the RAS cards. We think you would be hard-pressed to find better management tools than those offered by Brooktrout.

The main tool is the Remote Access Manager (RAM). This software offers strong control over RAS services by giving you management information about the cards themselves and then letting you set RAS service policies across the remote user population. It gives you dynamic snapshots of all RAS port statistics inside an easy-to-use graphical user interface. RAM gives you enough information so you can analyze session usage for accounting and billing, and then set up any necessary access controls. The card also comes with a useful diagnostic monitor for determining the state of the firmware, the low-level line and D-channel status, which can help you ensure overall uptime.

Interphase and Eicon get high grades for management, as they both bundle Acotec's RAS management software with their products. Also called Remote Access Manager (RAM), this software lets you manage RAS resources and set access controls for individuals and groups of users. Acotec's RAM also provides RAS usage accounting, reporting and event logging statistics.

Additionally, Eicon's Diva Server PRI ships with useful monitoring tools such as a line-check utility that verifies whether the Diva adapter is functioning properly with an ISDN line. The management features of Ariel's RS2000 are limited to the configuration utility that is available via the control panel once the card software has been installed. This provides a simple means of changing the properties of the network ports and can be used to modify a line's parameters and modify modem configuration, and it offers some limited diagnostic features. For RAS policy management, the RS2000 hooks directly into NT's Routing and Remote Access Services (RRAS).

Digi takes the same tack regarding RAS management as Ariel. The DataFire RAS PT1 ships with a console-based tool for configuration of the card and connecting lines. Additionally, there are console- and Web-based tools that let you monitor the status of the host adapter, the T-1 lines and trace calls.

However, Digi defers to NT RRAS for policy management.

Each of the cards we tested has a few unique features that can help them stand out. Digi's DataFire RAS PT1 has digital signal processors that provide advanced modem and fax support. Its channels operate independently of each other and can automatically adjust to support analog or digital connections.

The card also supports the broadest range of operating systems, including Unix, OS/2 and NetWare.

The IRAS-24A adapter ships with Brooktrout's Netaccess AnyCall technology, which lets the cards autonegotiate any type of incoming ISDN, 56K-bps modem calls and 33.6K-bps or lower analog modem calls. It also ships with an integrated CSU option that eliminates the need for an expensive external CSU device.

Interphase's Entia 5536 and Eicon's Diva Server PRI ship with an on-board Reduced Instruction Set Computing processor that helps off-load server processing duties. The Entia 5536 can simultaneously process ISDN and analog sessions. Diva Server PRI ships with optional digital-only or digital/analog communications over ISDN and can be upgraded easily with software downloaded from Eicon's Web site.

While we tested the performance of each of these cards only in a 24-port configuration, it is still important to consider how well these cards can scale to accommodate a growing number of remote users.

Digi's DataFire RAS PT1 and Ariel's RS2000 collected top honors in this category because both cards can be configured to accommodate up to 60 simultaneous remote sessions in a single PCI slot. Additionally, you can plug four Digi cards or two Ariel cards into a single NT server to get a total of 240 and 120 RAS connections, respectively. Brooktrout's IRAS-24A and Eicon's Diva Server PRI support 23 connections per card. You can plug four of each of these cards into an NT server.

While none of these cards were onerous to install, Digi's DataFire RAS PT1 and Interphase's Entia 5536 were the easiest to plug into the NT box. If you have installed a standard network interface card or modem before, you will not have a problem with these cards, as both have graphical interfaces that walk you through the process. The only installation issues we found across the cards were that Ariel's RS2000 requires NT RRAS to be resident on the box before you can begin the card installation process, and the installation process of Brooktrout's IRAS-24A was not as intuitive as we would have liked.

As for documentation, Brooktrout's IRAS-24A hard copy was well-organized and well-indexed, and its online reference guide is an invaluable resource for troubleshooting. Digi's DataFire RAS PT1 online documentation was accessible via a browser, which made it very easy to navigate. Interphase's Entia 5536 hard-copy documentation included detailed illustrations and helpful screenshots but provided no online documentation.

While Brooktrout's IRAS-24A was the overall winner in this comparison because it was the fastest and most manageable of the lot, any one of these NT-based RAS cards will help you give remote users access to your corporate network.

Van Cleve is network project manager at XXCAL Testing Laboratories, a worldwide independent test lab specializing in software and hardware compatibility, functionality and performance testing in Los Angeles. He can be reached

XXCAL is also a member of the Network World Test Alliance, a cooperative of the premier reviewers in the network industry, each bringing to bear years of practical experience on every review. For more Test Alliance information, including what it takes to become a member, go to

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