A FRAD for every outpost

Simple devices, subtle distinctions. That's what we found when we took a look at the midrange FRAD market.

We tested four FRADs in the $1,500 to $4,500 range that could carry multiple protocols (TCP/IP, IPX and SNA) between geographically distant Ethernet segments. Voice capability was optional. All four products performed well, but Ericsson Datacom Access, which acquired Advanced Computer Communications in November, won our Blue Ribbon Award. Ericsson's Colorado Rapid device delivered the most consistent performance across variously scaled setups, though it wasn't as easy to administer as ACT Networks' two contenders, the NetPerformer SDM-9350 and SDM-9400. ACT gained the administrative edge with its ACTView 2000 network management software, which ACT bundles for users of Hewlett-Packard's OpenView. In the installation race, FastComm Communications' EtherFRAD F9200 was the easiest to get up and running. (We invited other market share leaders Motorola, Nortel Networks and Cisco to submit their FRADs for review, but each declined our invitation.)

For the most part, our tests didn't reveal anything unusual. Each of the FRADs provided more than adequate bandwidth for the branch office WAN connections we established, and we found the FRADs no more difficult to administer than any other processor-based network component. We would have no qualms about putting any of them to use in a branch office frame relay environment.

The speed with which these devices rearranged network data into frame relay cells depended heavily on the processing power and amount of available memory in each device. All three vendors offer a range of FRADs for different applications. We found we could buy what we needed just by giving each vendor an accurate picture of the amount and type of network traffic we expected each permanent virtual circuit (PVC) to carry.

WAN links that zing

In the lab, all four devices transferred uncompressed data files via frame relay at about the same rate. When we enabled compression on a 56K bit/sec link, however, Ericsson's Colorado Rapid FRAD easily outran the competition, thanks to its efficiently programmed proprietary compression scheme. But the downside of Ericsson's compression approach, which is modeled on the Stac LZS algorithm, is that it forces you to use Ericsson FRADs at both ends of the WAN link, eliminating any chance of FRAD interoperability. We were also disappointed to find that we couldn't take advantage of compression in our high-speed connections. At T-1 and E-1 speeds, the time it took to compress each network packet caused a bottleneck with all the FRADs we tested.

With uncompressed data, Ericsson's Colorado Rapid and ACT Networks' SDM-9350 processed IPX packets slightly slower than TCP/IP or SNA packets. In low-speed tests, FastComm's Ether-FRAD handled IPX packets well, but its IP performance wasn't quite as fast as that of the SDM-9350. The SDM-9400 transferred uncompressed packets just slightly faster than the other three devices.

The ACT Networks devices did a superior job of carrying digitized voice signals across the WAN link when we simultaneously sent data and voice across the link. Moreover, the SDM-9350 and SDM-9400 let us concentrate frame relay traffic from multiple FRADs onto a single frame relay connection, which meant we needed fewer PVCs to carry our data.

We found all the units scaled well across a variety of branch office WAN links with different traffic requirements. As we emulated widely different branch office environments, we found Ericsson's Colorado Rapid gave us the most consistent throughput regardless of the mix of traffic volumes and protocol types we imposed on each frame relay link. For its part, the SDM-9400 didn't even break a sweat when we forced it to handle a 75% utilization load at T-1 speeds. The Ether-FRAD wasn't as consistent across extremely wide ranges of utilization, yet it behaved well within the confines of small to mid-size branch office use.

FRAD management

Ease of administration is nearly as important as performance when you're choosing a FRAD.

ACT's ACTView 2000 network management software turned the maintenance and monitoring of the SDM-9350 and SDM-9400 into child's play. In the lab, it gave us an intuitive graphical interface for observing the real-time behavior of SNMP-capable FRADs. If you use OpenView, the combination of ACT's FRADs and management software slides easily into your network. However, network administrators who don't use OpenView will find themselves referring to the user manual frequently as they configure the SDM-9350 or SDM-9400 through its telnet interface.

All four FRAD devices let us perform configuration tasks through a separate port, via telnet, as well as in-band over the network. The EtherFRAD F9200 telnet interface was simplest and easiest to use, while Ericsson's Colorado Rapid telnet interface was somewhat complicated though comprehensive. Ericsson's supplies a wealth of configuration options, including detailed data filtering at the Data Link Connection Identifier, which allows you to identify each PVC, to use bandwidth judiciously between remote sites.

In our tests, we configured Ericsson's Colorado Rapid to filter IP and IPX traffic based on source/destination, subnet mask and other criteria. The SDM-9350 and SDM-9400 also let us configure IP address filters, via ACTView 2000, but the EtherFRAD's filtering ability was limited. Nonetheless, the EtherFRAD's Fastick modules automatically distinguished between Data Terminal Equipment and Data Communication Equipment, a feature that helps reduce cable setup problems. We liked the EtherFRAD's option of letting us toggle its integrated

T-1/E-1 DSU/CSU on and off according to the speed of the link we established. FastComm's design offers multiple ports for routing over frame relay and most common serial-based routing protocols - a big advantage for growing networks that require reconfiguring over time.

As for supporting standards, our tests showed all four FRAD products adhere to the RFC 1490 frame relay standard. As long as we didn't turn compression on, the products interoperated well. We were especially pleased to see units from different vendors successfully exchange IPX routing (Routing Information Protocol) traffic, SNA traffic and several types of IP traffic, including Address Resolution Protocol and Internet Control Message Protocol.

After working with these FRADs, we concluded that most users will have to develop custom network-specific setup instructions if they plan to deploy dozens or hundreds of devices in an enterprise setting. The documentation the vendors provide is just too general for most users. This is particularly true in the case of FastComm, which attempts to cover several different EtherFRAD models in one booklet. ACT's SDM-9350 and SDM-9400 user guides were product-specific and did a good job of explaining frame relay concepts. Of the three vendors' manuals, Ericsson's Colorado Rapid manuals were the most thorough.

Getting all these units up and running was simple enough after we decoded the manuals, but the EtherFRAD pleasantly surprised us with the quickest, easiest installation.

The straightforward, clean design of the EtherFRAD's remote telnet configuration screens makes it an ideal candidate for use at small remote sites that you never expect a network administrator to visit.

We were amazed to find that we could probably send an EtherFRAD to a remote site, have an untrained clerk or assistant make some simple network cable connections while we supplied over-the-phone guidance and then put the EtherFRAD to work after making some configuration changes remotely over the network.

It's just this kind of simplicity that reminds us why users migrate from expensive point-to-point lines to frame relay. Check with vendors; more likely than not there's more than one FRAD out there that can handle the traffic you expect each PVC to carry.

RELATED LINKS How we did it
Our testing methodology.

Talk is cheap with frame relay
A look at where the FRAD market is heading. Network World, 1/18/99.

Interactive FRADs buyer's guide
Use our database to find the FRAD that best meets your requirements. Includes a configuration calculator for seeing how much a specific FRAD would cost based on options you select.

Network World Fusion Focus on Frame Relay
Archive for our twice-weekly newsletter on frame relay.

Frame relay Net Resources
Additional links to frame relay info.

Nance, a computer analyst and consultant for 28 years, is the author of Introduction to Networking, 4th Edition (Que, 1997) and Client/Server LAN Programming (Que, 1994). He can be reached at barryn@erols.com.