3Com's configuration consisted of three CoreBuilder 7000 HD ATM switches, with a variety of ATM, Fast Ethernet and Gigabit Ethernet interfaces on board. The edge of the network was serviced by a 12-port SuperStack II 3000 ATM edge device, which provided 12 ports of 10/100 Layer-2 connectivity to the network. Routing was accomplished by passing Gigabit Ethernet from the CoreBuilder 7000 HD into 3Com's award-winning CoreBuilder 3500 Layer 3 switch. In addition, 3Com brought its CoreBuilder 9000 Enterprise ATM backbone switch. However, this switch was not part of our test network because of the prohibition against using beta code during this test.

3Com's CoreBuilder 7000 HD was one of the most versatile ATM switches we've tested. In addition to OC-3 and OC-12 modules, the 7000HD supported Ethernet, Fast Ethernet, Gigabit Ethernet, and T1/E1 and T3/E3 services. The CoreBuilder 7000 HD can be configured from a menu-driven command-line interface or via Transcend, 3Com's enterprise-level management software.

The CoreBuilder 3500 brought Layer 3 functionality to 3Com's solution. Four Gigabit Ethernet uplinks provided ample room for the traffic generated by our tests. We were disappointed, however, that 3Com could not provide a native ATM interface for CoreBuilder 3500, as this had been promised for the early half of 1998, when we last tested the product (see www.networkcomputing.com/909/909f139.html). Using Gigabit Ethernet as the routing medium provided ample bandwidth, but the cell-frame-cell conversion forfeits the native nature of ATM technology, leaving us with a hybrid solution at the core of the network.

3Com's solution was unique in that it can serve as a highly resilient core for a gigabit network. By using ATM solely at the core of the network, with gigabit interfaces to all the edge devices, you can take advantage of all the scalability and resiliency of ATM without dealing with the LANE headaches. Kudos to 3Com for developing a switch to bridge the gap between Gigabit Ethernet and OC-12 ATM.

At press time, 3Com stated that MPOA functionality would be available by the end of 1998. The network we tested was based on a proprietary hybrid IISP-PNNI topology. 3Com's version 4.0 software (which was in beta during our tests) addresses this proprietary feature, and adds other standards-based improvements to CoreBuilder 7000 HD.

3Com fared poorly in our lab signaling tests, garnering a mere 15 calls per second at best. Many of our tests were incomplete due to signaling issues between CoreBuilder and the Smartbits tester. No problems arose regarding interoperation with the AG Communications video server, and MPEG-2 video passed across the network under full load without suffering from performance degradation.

Olicom
Of all the vendors who provided products for our tests, Olicom was the least prepared. The Olicom solution consisted of two CrossFire 9200 5-Gbps ATM switches and a CrossFire 8420 10/100 Ethernet edge device. Olicom's solution clearly lacked the insight and planning that was evident in its competitors' presentations. Olicom's products are simple to configure and easy to manage, and they conform to nearly all available ATM Forum standards. The price is right on target, too; unfortunately, the execution was not.

Olicom's setup consisted of two CrossFire 9200 ATM switches connected via four OC-3 multimode links. Olicom was unable to provide the OC-12 single-mode, long-haul interfaces necessary to complete the proposed network. And no router was provided, so we flattened our network into one domain and ran our benchmarks without routing. For edge connectivity, Olicom provided the 8420 Fast Ethernet edge switch.

The CrossFire 9200 is identical to its smaller brother, the CrossFire 9100 (see our review of the CrossFire 9100 at www.networkcomputing.com/821/821f2.html), except that it offers twice the capacity (5 Gbps per switch) and twice as many interfaces (up to 32 OC-3s or seven OC-12 interfaces per chassis). When we tested this switch a year ago, it was at the cutting edge--it had features other vendors were still only thinking about implementing. One year later, with nearly the same feature set, this switch is no longer the marvel it used to be.

CrossFire 9200 has hot-swappable line cards and a redundant power supply, but it sports only a single switching engine, with no backup, making it a potential single point of failure in your network. It supports LANE but not MPOA, and Olicom reports that it has no plans to offer any MPOA solution at this time. PNNI routing is standard, as are hitless code updates, according to Olicom's on-site engineer.

In our tests, CrossFire 9200 fared very well, averaging 120 to 150 calls per second. Unfortunately, it had unresolvable interoperability problems with FORE's ATM NICs. We were forced to use Olicom ATM NICs in our clients and servers in order to get the network to come up properly. We encountered no problems during the video test, and saturation had no adverse effect on video quality.

Olicom has a real gem of a switch for middle-of-the-road ATM applications. Based on its contribution to this test scenario, we'd have to recommend that it stay right there--in the middle of the road. On the edge, the CrossFire 8420 is a good value for 10/100 Fast Ethernet to ATM connectivity, but be careful to check for interoperability before signing on the dotted line.

Send your comments on this article to Joel Conover at jconover@nwc.com.

We wish to thank the following vendors for providing equipment and services for our testing for this article: AG Communication Systems for ATIUM VIA 188; Fluke Corp. for OC3port Plus; Hewlett-Packard Co. for HP Internet Advisor; and Netcom Systems for Smartbits.