Smokin' Remote Access Pushed To The Max: Part II
We uncovered several problems with the Tigris during our testing that simply should not be found in a shipping product. The Tigris failed to identify misconfigured compression packets and subsequently failed to stop attempting CCP compression or drop the connection. The result was garbage across the link. Once we resumed testing, results were still alarmingly slow. After another call to ACC, we learned that there was a problem in the V.42 compression scheme and that turning it off would improve performance. We did note an improvement in performance, but it was still double the average of the other servers. ACC states that there is a problem with a low-level driver that forwards packets from the modems to the network stack. If a connection is up for longer than 10 to 15 minutes, the driver would choke and stop passing data. Another firmware fix was issued, but the sluggish throughput remained. At the time we went to press, ACC said it was still working on the problem.
ACC's command-line interface and its cryptic commands left us scratching our heads on more than one occasion. On a more positive note, however, we did receive an early look at a the company's RiverView SNMP management product. RiverView, which is designed for the Tigris, will run with CastleRock's SNMPc application, the company says. It shows much promise and will greatly facilitate easier configuration and management.
Mike Fratto can be reached at mfratto@nwc.com.
Testing Enterprise Remote Access
Although we tested only analog connections, most of the servers can handle both analog and ISDN PRI simultaneously.
Our performance testing was designed specifically to stress servers with a constant stream of traffic--down to each of the 96 simultaneous ports tested.
Instead of rounding up 96 computers and trying to coordinate their communications, we used two Micron Millennia Pro 200-MHz servers, each configured with a 48-port Digi EPC/CON multiport serial board. The servers ran Windows NT 4.0; 48 dial-up networking clients were created, each with its own preconfigured IP address and separate Class C network to ensure that data was passed down every port, rather than down the first port of the subnet. We used V.34 modems topping out at 33.6 with V.42 compression. On the dial-out side, two Compaq Computer Corp. Microcom 6100 chassis were connected to a Madge Networks Teleos Model 60 T1/PRI switch via a T1 connection. Funk Software's Steel-Belted Radius provided user authentication.
The majority of the severs came in with transfer times between 5.5 KB to 7.5 KB per second for IP and IPX file transfers. The Access Beyond AB4400 and Bay Networks Model 5399 offered the fastest overall throughput. ACC Tigris came in a disappointing last with no transfer times greater than 3 KB per second.
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