Digitech’s RAS 3.9x has the best user’s manual that we’ve seen in two
years — and fortunately, the product is pretty good, too.
But don’t confuse RAS with a remote authentication server. In this case,
“RAS” stands for Remote Analysis System. It’s a rack-mountable tool for
network and protocol evaluation, and it has some great applications for the voice- and
fax-over-IP industries. The product also offers users the choice of three different client
types, transmission speeds for 10/100 MB Ethernet and 4/16 MB token ring, and a traffic
capture option for taking and evaluating real-time snapshots of actual network conditions.
Additionally, all processing is done within the unit itself — the client applications
only mirror the results. Even better, because it lives with a static IP address, it is
accessible from anywhere on the network (whether the node is wired, wireless, dial-in, or
VPN) using a Web browser, a pure-Java application (with an OS that supports it), or with a
client application.
INSTALLATION
The RAS unit fits nicely in a rack, although we didn’t happen to mount it that way in
the laboratory. Instead, it fit nicely in a shelf surrounded by other products’
over-engineered press kits. To begin the installation, we plugged in a standard PC power
cord, and we attached it to the corporate LAN with a standard Ethernet wire. We switched
on the power, and the unit came to life and ran a POST process. We immediately noticed
that it was rather loud — more so than a standard industrial computer — but for
laboratory or MIS uses, this isn’t a big deal.
The box is very easy to configure; other than the cabling, just four buttons control
its behavior, with all settings controlled through a small LCD. Users configure the date
and time, server name, server password, IP address, subnet mask, gateway, secondary
gateway, dial-up IP address, and dial-up subnet. You can also configure the number of
clients. Entering “0.0.0.0” for the IP addresses and subnet masks lets you
configure a DHCP option. You can also configure the remote control options and shutdown or
reboot the device from this interface. The entire set-up process was very easy to learn,
and was completed in about 15 minutes.
The next step is configuring the client(s) that you prefer. With a 4.x or newer version
of Microsoft’s Internet Explorer or Netscape’s Navigator, the easiest method is
to browse to the unit’s IP address. This involves precisely setting up security
options, but the specifics of how to do this are explained thoroughly in the manual. If
the security requirements are a problem for you, you can instead run the Java client or
the Windows client. To access either of these, you browse to the unit’s homepage and
download the appropriate version.
DOCUMENTATION
At TMC Labs, we believe that no product or product manual is ever perfect: Features can be
improved; protocol compliance can be expanded; manuals can be easier to understand. But in
the case of this product’s printed user manual, it’s very, very close to
perfect. The wire-bound user’s guide in question has about 160 pages. It is neatly
divided into eight chapters and three appendices, and it includes a “summary of
changes” section. The table of contents is organized so that it’s easy to spot
subject headings. Best of all, through the appropriate use of diagrams and well-timed
screen captures, every feature and concept is explained in language simply enough for
entry-level MIS/IT personnel. Every feature has a clearly written thesis sentence, and the
feature and section organization is impeccable. Contact information for Digitech is also
readily available.
Now for the bad news: The four-page physical configuration pamphlet is equally
informative, although we did find a noticeable amount of typographical/grammatical errors.
(Even in the actual interface, the word “simulate” is incorrectly spelled
throughout the application.) The online help also retains the solid organization and
useful information, but its interface design is quite poor — it’s not resizable,
you can only read small parts at a time, and it is not context-sensitive. We extend our
compliments to the Digitech technical writers for the user manual, but the online help
(and the installation guide, to a lesser degree) need improvement.
FEATURES
The RAS interface is virtually the same whether you’re in the Web view, the
stand-alone view, or the Java view. Basically, it’s a DOS-like GUI — think of
WordPerfect 5.0 with its macro templates, or the old MSN.EXE diagnostic utility. The
menu’s top horizontal pane shows the system state, operating mode, open file,
information/help messages, and time. The menu’s bottom pane shows menu-specific
function keys with labels. In the middle, the active window always has a bright color
border, and the non-active windows have a gray border. The default main menu is very
clean; it contains only some basic title information and the bottom function keys, but no
windows. If you get lost navigating the menus, pressing the escape key brings you back a
level.
In the main menu, the function keys have these uses: F1, configure testing/monitoring;
F2, monitor traffic; F3, analyze traffic by destination/source addresses and by
protocol/frame type; F4, simulate network traffic; F5, perform expert traffic analysis;
F10, quit the RAS session. Also, pressing shift-F3 shows the system version, and pressing
shift-F4 displays system memory information. There are many other navigation commands
throughout the product, but they’re all well documented.
There are several other features that we like. In most views, users can choose from
multiple views. Files captured from other locations’ RAS servers can be imported, or,
you can monitor and capture the date in real time. A filtering option lets you include or
exclude particular frames, layers, protocols, instances, etc., which is an effective way
to troubleshoot any kind of connection or application. Filtering for ASCII strings, frame
errors, or hexadecimal patterns can also configure views, and RAS can also decode many
network messages. Within the user’s manual, there is a protocol decodes section,
dedicated to discussions of TCP/IP, Novell IPX, AppleTalk Phase 2, DECnet Phase IV, IBM
Protocol, Banyan VINES, XNS, SUN Protocol, and OSI. For good measure, they also include
Microsoft, router, and IP telephony protocols.
OPERATIONAL TESTING
There is a lot to learn to become a proficient RAS user. Even learning how to
navigate the menus is a chore; it’s much like using Windows with lots of DOS screens
and no mouse, even in the browser mode. The only possible benefit to working this way is
that it might cause you to work slower and more precisely, but we feel strongly that there
should be a better Windows client with buttons instead of keyboard macros.
You use RAS by selecting one configuration at a time, which stays active as you scroll
through the modes for monitor, analyze, expert, and simulate. Pressing F1 calls the
configuration menu. For our first test, we configured a fast Ethernet interface and we set
the interface type to auto-detect (as opposed to 100Base-TX, 100Base-T4, etc.). Pressing
“okay” (or Alt-O) saves and closes this menu. We decided to run this test by
capturing a sample of our office traffic, which includes TMC Labs, the rest of the
editorial department, and the art department. To do this, you enter the configuration
mode, and then enter the capture mode (by pressing F1 and then F2.) We created a 25 MB
file called “tmc labs.dat” using the default options. To start the capturing
process, press F5.
We tested this product during a three-month period in late 1999. During that time, we
linked the RAS to several other products that we were reviewing, including a Windows
NT-based unified messaging server, an ISDN router, and a black-box Internet telephony
appliance. When extra time was available, we also tested the RAS with a NetMeeting video
conference.
There isn’t enough space here to thoroughly discuss the results of each test.
However, we can tell you this: Each test, in some way, showed how an analysis platform
like Digitech’s is useful. For example, imagine that the Free Speech IPT Corp. was
testing its new SIP gatekeepers and T1 gateway cards. When they began a test, they might
do things the TMC Labs way, and use a T1 simulator — like those from Gordon Kapes or Teltone
— instead of using an actual T1 line. Doing this eliminates a lot of variables in the
connection stage, which lets the Free Speech engineers focus on their own product instead.
Then, they would use a bulk call generator and call quality testing package, like the
Hammer IT system. At this point, stop and consider the situation: The R&D employees
have simulated connections to the outside world, and they have a stress-tester, but they
have no way of examining individual frames, layers, or protocols if problems should arise.
It’s true that there are Windows-based WAN emulators, and even a Linux-based WAN
emulator that we know of, but these products, while easier to learn and use, do not match
the level of drill-down analysis found in the RAS product.
For another example, look at the images in Figures 3 and 4, which are the fifth and
last frames of a 718-frame sample VoIP file included with the RAS. In frame five, you can
see that traffic’s first UDP message, fragmentation warnings (fragmenting is when a
packet self-divides because it might not fit through the given bandwidth), the packet
prioritization scheme, delay, and destination address. Beneath this information you can
see details of the packet’s structure. Now, look at Figure 4, which is frame 718.
Here, you can see that this is an RTP frame, with its own set of unique identifiers and
addressing messages. Also, note how the date decode section has changed. We have to admit,
though, once you decipher how to use this product, it’s actually fun to put your
applications under so powerful a microscope.
ROOM FOR IMPROVEMENT & CONCLUSION
This product is not for the inexperienced. We strongly recommend that this
product only be used by experts, and by people who truly understand the nuances of the
network types they’re working with. Too much information at this level of detail can
be dangerous in the wrong hands. True, the instruction manual is excellent, as was
Digitech’s technical support. But despite the RAS’s power, it is very, very
complicated. It would be hard to find a more powerful tool in this price range, but be
prepared for an education. RAS deserves our Editors’ Choice Award anyway, for being
the Mazda Miata of network tools: It’s inexpensive, very powerful, and frankly, it
brings enjoyment. (Editor’s note: The TMC Labs engineer who reviewed this
product just happens to drive a black on black, 1996, 5-speed Miata. Go figure!) |
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