REVIEWS

Get A Running Start On The Fast Track With 100-Mbps Switches And Hubs

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Building a Fast Ethernet network is a tough job. Throw your traditional Ethernet instincts out the door and get ready to think switched, faster and shorter. Fast Ethernet repeaters are limited to one hop of only 5 meters, severely limiting your network diameter. Of course, routers and switches will separate your collision domains and extend your network diameter across the entire campus. Two years ago, your only option was Bay Networks' 28115, a 16-port 10/100 Fast Ethernet switch that provided you added network diameter, switched networking and 10-Mbps legacy connectivity. Today, the picture is much bigger.

We tested five Fast Ethernet switches and a handful of stackable hubs at Network Computing's University of Wisconsin-Madison lab, t o give you a running start on the Fast Ethe rnet raceway. We tested the newest products from all the big players --> To help you extend your network, we tested stackable hubs from seven vendors, including Intel, UB Networks, Matrox, Asante, 3Com, Cabletron and Cogent. All hubs have at least a dozen shared Fast Ethernet ports, and they all stack at least five units tall. Stackable units, like the ones we tested, allow you to get your workgroups online cost-effectively while leaving room for future growth.

Most of the hardware we tested is 100BASE-TX or FX. Two notable exceptions are 3Com's Superstack II series and Cogent's S-1200 hub. Both vendors have stuck with the 100BASE-T4 standard to bring you the added option of Category 3 wire. Of these two vendors, we prefer the 3Com solution. You can stack the 100BASE-TX, FX and T4 hubs into a single unit, providing a way to mesh TX and T4 shops into a unified network. Intel will be offering a similar T4 solution later this year.

Switch On To Fast Ethernet

Building a network of entirely switched ports is appealing but cost-prohibitive. Switched networks give you more bandwidth, less congested segments, more control over your network and better management statistics. Switching is mission-critical in the world of Fast Ethernet, where all repeaters are limited to one repeater hop at best.

Choosing the right Fast Ethernet switch will depend on your networking needs. If holding down costs is your primary objective the 3Com and Intel switches both come in under $1,000 per port. If 10-Mbps connectivity is an issue, Bay Networks, Cisco and Cabletron have ways o f getting you connected. Finally, if high-density switched ports are your primary concern, start with Cisco and Cabletron. Both vendors offer at least 16 Fast Ethernet ports with expansion options.

3Com Corp. Superstack II Switch 3000TX

Of the switches we tested, we found that the 3Com Superstack II Switch 3000TX had the best price-to-feat ure ratio. The 3000TX offers eight 100BASE-TX-only port s at about $1,000 per port, which appears to be the status quo for Fast Ethernet switches. What gives the 3000TX an edge over other switches in this category is its excellent management features. The 3000TX offers seven groups of RMON plus telnet and SNMP management facilities, making at-a-glance network management a snap.

The Superstack II Switch 3000TX (formerly the LinkSwitch 3000) is a great solution for shops that require affordable Fast Ethernet switching with numerous management options. Getting the 3000TX up and running was quick and painless--unbox it, plug it in, configure the IP address and you're ready to go. Switch configuration was driven by a full-screen menu-driven interface.

The Switch 3000TX has eight 100BASE-TX Fast Ethernet ports plus a modular uplink port in the rear. It has an 800-Mbps backplane, sufficient to handle most any switched traffic you'd encounter across this switch. With 4,080 MAC addresses in the address table the Switch 3000TX fits in nicely as a segment switch for use with several stacks of Fast Ethernet hubs.

On the management side we were extremely pleased. The Switch 3000 TX supports all the RMON groups except capture and filter. When meshed with Transcend Enterprise Manager 5.0 for Windows95/NT or Unix, you've got a powerful set of tools capable of helping you troubleshoot networking problems and keeping a preventative eye on network-wide traffic flow. Transcend 5.0 is 3Com's latest incarnation of its management software and includes RMON analysis software, network layout view and front-panel viewers for all of the Superstack II line. Transcend als o lets you build and edit virtual LANs (VLANs) across any of your 3Com switching infrastructure via a proprietary packet-tagging technology.

In addition to its extensive management features, the 3Com switch supports several unique features, like a redundant power supply option, backpressure flow control, broadcast storm filtering, access control filteri ng, proprietary PACE priority signaling and switch-spanning V LANs. Bay Networks and Cisco offer similar features but have higher price tags.

The only fault we could find in the 3Com Superstack II Switch 3000TX was its inability to connect to legacy LANs. The 3000TX has no support for 10BASE-T connections, making a 10/100 bridge or router a necessity for integrating Fast Ethernet into your existing LAN. 3Com does promise spanning tree support and an ATM uplink later this year, but it would be nice to see FDDI or 10-Mbps adapter for the Superstack rear expansion port.

Bay Networks Model 28200 Modular Fast Ethernet Switch

The Bay Networks 28200 is the most recent product in Bay Networks Fast Ethernet switching line. Unlike its predecessor, the Model 28115, the 28200 sports a modular chassis capable of holding four Media Dependent Adapters (MDAs). The bare chassis must then be populated with either 2-port 100BASE-TX or FX MDAs, or 8-port 10BASE-T MDAs. The 28200 can hold u p to 8 100BASE-T connections, 32 10BASE-T connections, or a mix and match of both. With its maximum configuration of 8 100BASE-T connections, the 28200 sells for $12,970, or about $1,370 per Fast Ethernet port.

Setting up the 28200 was relatively simple. After unboxing the switch and installing the MDAs, our console revealed an ASCII-based menuing system. From the console you can configure the operational aspects of the switch and the individual MDAs. The MDAs we installed only occupied half the available slot space and internally, only half the bus was used on each slot.

We speculate that Bay Networks will offer higher density MDAs in the future, although Bay w ould neither confirm nor deny our speculation. The 28200 has a robust 2-Gbps backplane, support for up to 1,024 MAC addresses per port with a total of 8,192 across the switching community. The "switching community" encompasses all of the 28200 switches you define within a given workgroup. While the other switches we tested only support VLA Ns on a per-port basis, the 28200 offers support for both port and MAC address-based VLANs. Additionally, it can support up to 1,024 MAC addresses per VLAN. Features which make the 28200 stand out of the crowd include proprietary backpressure flow control, MAC-based VLANs, redundant link and load balancing support and hot swappable modules.

Managing the 28200 was accomplished through the Optivity Campus 6.0 for Windows95, which is based on HP OpenView. Optivity was the best network management platform we tested. The network topology and autodiscovery mapping features were unmatched. With the Campus Control Center (CCC), Bay Networks has added more to HP OpenView than just a front panel viewer. The CCC gives you a summarized view of all the Bay Networks equipment on your LAN and allows you to invoke the panel viewers, RMON probes and VLAN management tools that are associated with each device.

Because we had only one Bay Networks switch on our LAN, some of the useful features, like the ability to gr oup hardware into custom "tabs" such as by floor or department, weren't t ested. The CCC is an excellent standalone application, and indeed, Bay Networks sells a version without HP OpenView called EasyLAN Manager. With or without OpenView, the CCC gives you an at-your-fingertips look at the health of your network and an easy-to-use interface to all the advanced features the company provides.

Bay Networks plans to release version 2.0 of its switch, along with several new MDAs, including a FDDI uplink, a 10-Mbps RMON probe that supports all nine groups of RMON and a stack uplink later this year. The uplink will allow you to connect multiple 28200s together at distances of up to 2 km in a stacked architecture at a speed of 400 Mbps.

Cisco Systems Catalyst 5000

The Cisco Catalyst 5000 is the most expandable switch we tested. With up to 50 ports of switched autonegotiating 10/100 Fast Ethernet, the Catalyst 5000 has the highest port density. For Fast Ethernet switching we f elt the 1.2-Gbps backplane was a little sparse for a high-end switch like the C atalyst 5000. On the other hand, Catalyst's 16,000 address MAC table is more than sufficient for even the largest workgroup segments.

Cisco's strong points in the Fast Ethernet arena are its VLAN support, rugged design, including redundant load-sharing power supplies and chassis architecture, and its hot swapable architecture. In addition to the 100BASE-TX 12 port module that we tested, the Catalyst 5000 can take a 12-port FX module, ATM, FDDI, CDDI and 10BASE-T and FL uplinks. All these combine to make an excellent and highly reliable multi-medium switch.

Managing the Catalyst 5000 is performed via CiscoWorks for Switched Internetworks, a combination of the Cisco VLAN Director utility, Cisco Traffic Director and CiscoView, Cisco's network-topology mapping tool. These utilities come together to manage your entire Cisco enterprise network, including routers, switches and workstations.

The Catalyst 5000 supports four groups of RMON and VLANs on a per-port basis. Setting up VLANs is done through the VLAN Director. Collecting RMON data out of the switch is accomplished with the CiscoWorks Traffic Director program. The CiscoWorks package is yet another entry in the total network management arena. Our biggest disappointment was that it is currently available only for SunOS. Cisco is now in beta with a version for Windows NT.

Intel Corp. Intel Express 100BASE-TX Switching Hub

The Intel Express 100BASE-TX Switching Hub is a 5-port Ethernet switch with two slots available for additional TX or FX modules. We felt the Express switch was slightly under-powered, with only a 250-Mbps backplane t o support five to seven connections and its 1,024 address MAC table was the smallest address space of all switches tested. All the ports on the Express switch are 100-Mbps Fast Ethernet only, so you'll need a bridge or router to connect to your legacy LAN. Intel's switch supports backpressure flow control and the RMON statistics group for easier LAN management. The Express switch also support s port mirroring and VLANs, although Intel warned that creating VLANs across switches wasn't recommended for this release of the switch.

Managing the Intel line of switches and hubs is performed via the newly released Intel LANDesk Network Manager for Windows. First-time users will find LDM a breeze to install and configure, thanks to well-written install and help utilities. LANDesk manager can be run standalone, but also detects installed copies of HP OpenView and offers to install itself as a subapplication of OpenView.

The first time you run LANDesk Manager, you are presented with a help menu that tells you exactly how to begin building your network topology diagram via the autodiscovery mechanism built into the program. After finding all the nodes on your network, LANDesk Manager builds a layered network map from which you can manage all your Intel devices plus any others for which you have compilable MIB definition files. LANDesk Manager provides all the basic SNMP statistics and front panel viewers you would expect from a network management program, plus rudimentary RMON graphing utilities. While not as robust as HP OpenView or Optivity, the LANDesk Manager does provide a graphical RMON viewer for under $1,000.

Cabletron Systems FN100 Fast Ethernet Switch

The Cabletron FN100 Fast Ethernet switch is well-built and rich in features; however, it carries a hefty retail price. The FN100 is available in four fixed config urations: a 7 TX port plus one shared TX/FX port configuration; a 14 TX port plus two shared TX/FX ports; as well as 8- and 16-port FX models. The FN100 has no slots for expansion modules, but does support 10/100 autonegotiation on every port. Cabletron's switch has a 2.56-Gbps backplane, enough to support all 16 ports talking at full-duplex rates, with room to spare, and has an 8,192-entry MAC address table, making it a high-end segment switch. Since there ar e no expansion slots, connecting to your legacy LAN is limited to 10BASE-T connections.

Sett ing up the FN100 was a plug-and-play operation. It has several distinctive, proprietary feature. Two of the best are the virtual switch and trunking features. The FN100 can be configured into four separate virtual switches, each with its own 2-KB address table, allowing you to switch multiple physical networks on a single switch. The trunking feature allows you to dedicate up to eight ports that can be inter-switch links with other FN100 switches. Using this feature you can build a powerful 800-Mbps backbone among all of your switches, eliminating the conventional bottleneck typically found in Fast Ethernet networks.

Cabletron's VLAN support is somewhat awkward. The manual defined VLANs as workgroups, but had the same effect of limiting broadcast domains to a given group of ports. You can define up to 100 of these broadcast domains on a single switch, with individual ports belonging to multiple workgroups.

We tested a beta version of the FN100 management software, dubbed Spectrum Element Manager for Windows NT. The element manager was a little rough around the edges and still needs a lot of cosmetic work, but it was able to autodetect many of the SNMP managable switches in our test bed, and provided a tabular view similar to Bay Networks' CCC. From Spectrum Element Manager, you can monitor SNMP information in the FN100 and RMON data in manageable switches.

The FN100 supports broadcast and multicast filtering, but we couldn't configure these from the Eleme nt Manager. The Cabletron switch was the only switch that supported out-of-band management via a PPP serial connection. A future release of the switch software will support port mirroring to further aid in troubleshooting.

Stacked Tall and Proud

Stackable hubs complement your switched network by increasing port density without breaking the one repeater hop rule of Fast Ethernet (See "Class I and II Repeaters" on pa ge 144). We received hubs from about a dozen companies. Many of them, however, were cascadable only via fr ont-panel patch cables, and not truly stackable. Of the units we received, only those from Intel, UB Networks, 3Com, Asante, Cabletron, Cogent and Matrox were truly stackable.

Top honors go to two stackable hubs, the Asante Fast 100 stack and the Superstack II 100 from 3Com. The Asante units allow you to build a towering 15-unit stack, and its Class II architecture allows you to daisy-chain a second 15-unit stack for a total of 358 ports in a single collision domain. The 3Com Superstack II is a Class I repeater that stacks eight units tall but can interstack 100BASE-TX and T4. It also ships with a slot for an uplink module for added FX and TX connectivity. Both vendors offer a unit that stacks in and adds powerful management features.

3Com Corp. Superstack II Hub 100 TX

3Com has a winning combination with its Superstack II series. The Superstack II hubs we tested a re available in TX and T4 flavors that can stack together, up to eight units tall.

The Superstack II is a C lass I repeater with an optional redundant power supply and stackable management unit. The management unit has only one port--a serial port--but adds SNMP management plus telnet access and the first four groups of RMON. In addition to collecting statistics via telnet, the entire stack is manageable via Transcend Enterprise Manager. At just $2,499 per 12-port unit, the 3Com Superstack II is a great way to add affordable managed repeater ports.

vAsante Technolog ies Asante Fast 100 Hub

Asante has been in the stackable hubs business for a long time. It's no surprise that its Class II hub can stack up to 15 units tall, cascading to a second stack, for a total of 358 ports in a single collision domain. The Asante Fast 100 Hub also is one of the best priced hubs we've seen, at just $1,995 per unit.

The Asante Fast 100 is available in two configurations, a 12-port TX version and an 8-port TX version with an FX uplink. The Asante Fast stack also allows for a management unit to be s tacked in. Like 3Com, Asante chose a dedicated management box. The management unit has a console connection and a dedicated serial port for out-of-band management. The Asante Fast management unit allows telnet access as well as SNMP management, but lacks RMON abilities.

The AsanteView software used to manage the stack wasn't ready in time for our review, but we were able to monitor critical SNMP data via the telnet interface. While most vendors charge $80 to $120 for their stacking cables, every Asante hub ships with its own StackBus card which is used to stack the hubs together. The Asante TX hub has a redundant twelfth port used to simplify crossover connections.

Intel Corp. Intel Express 100BASE-TX Stackable Hub

The Express Hub from Intel is a 12-port 100BASE-TX repeater with two expansion slots. The first slot is capable of accepting a TX or FX upl ink card, while the second can take a slide-in management module or a second 12-port interface card. Intel isn't currently of fering the 12-port upgrade unit as an option, although it is documented in the manual.

We tested the repeater with the management module installed. The Express Hub is a Class I repeater that can stack six units high. It was designed in conjunction with Bay Networks and looks quite similar to the 28200 switch.

Switch management is performed via the LANDesk Network Manager suite. The 100BASE-TX hub plus management module supports SNMP management but no telnet or RMON capabilities. The Intel hub is competetively priced at $2,395, but we thought the $2,295 management module was overpriced when compared to units like 3Com's, which include RMON support at lower prices. One management module will manage the entire Intel stack.

Matrox Electronic Systems Matrox SHARK Fast Ethernet Hub

Matrox Electronics Systems, of video card fame, has entered the F ast Ethernet market with its SHARK Fast Ethernet Hub. The SHARK is a Class II 12-port repeater that can stack up to six units high. Although the SHARK Hub is currently unmanaged, the case was clearly designed to hold both managed and unmanaged units. Matrox affirmed that a managable unit is planned for the future.

Behind the steel plate on the rear of the SHARK hub we found a PCI-style connector for stacking the hub. The SHARK Fast Ethernet hub lists for just $1,695, making it the lowest-priced 12-port repeater we tested. The SHARK is equipped with a redundant twelfth port for MDI crossover connections.

UB Networks GeoStax/FE

The UB Networks GeoStax/FE is a robust 12-port repeater that can be purchased with or without management. Both versions have 12 ports, plus optional dual hot-swappable power supplies. Stacking a managed repeater in with up to four unmanaged units adds several powerful features, including RMON groups one through four, the ability to define up to th ree independent backplanes within the stack and the ability to limit traffic on a port to a single MAC address for security.

But all this comes at a price. The GeoStax/FE was one of the more expensive hubs we tested. The unmanaged unit lists for about $250 per port, while the managed unit lists for $333 per port. The managed unit is a 12-port repeater with cascading management functions, including cascading RMON. Managing the GeoStax/FE is performed via the NetDirector for Windows program, which is an HP OpenView-based management utility with custom plug-ins for UB products. The hub is managable via NetAssistant for Windows, an element manager for the GeoStax/FE.

Cogent Data Technologies

Cogent Data Technologies, recently acquired by Adaptec Corp. has been in the Fast Ethernet market since its onset. The S-800 FX and S-1200 TX and T4 hubs are competitively priced unmanaged hubs.

The Cogent hubs are Class I repeaters that can stack up to five units tall. The 100B ASE-TX and FX hubs can be intermixed for fiber-optic connectivity, but Cogent warned us against stacking the T4 unit because of compatibility pro blems. The 12-port twisted-pair hubs list for $2,098, while the 8-port fiber version is $3,998. The S-1200 has an MDI crossover selector on the twelfth port, a convenient feature when connecting to a switched network.

Cabletron Systems HubSTACK SEHI 100TX-22

The Cabletron SEHI 100TX-22 was the largest hub we tested, with 22 100BASE-TX ports and room for a TX or FX uplink. The SEHI is a managed Class I repeater with in- or out-of-band SNMP management. You can stack four SEH repeaters together with the managed SEHI repeater for a fully managed stack.

The SEH unmanaged repeater has room for two TX or FX uplinks. The Cabletron repeater lists for $7,995 managed or $6,995 unmanaged, and ships with the cable required for stacking. Management is accomplished via Spectrum Element Manager for Windows NT or StackView, a lower-end applica tion designed to manage the SEH and MMAC series repeaters. The SEHI has no support for RMON or telnet access.

Joel Conover can be reached at jcono ver@nwc.com.

Class I vs. Class II Repeaters

In addition to the new distance and wiring limitations of Fast Ethernet, the network administrator must also deal with new hub designations, namely Class I and Class II repeaters. Vendors will argue that one is better than the other, but each has its own merits.

A Class I repeater is a device that fully decodes the analog wire signals into a digital representation. Because all of the data is represented digitally inside the hub, it is po ssible to mix media types such as 100BASE-TX and 100BASE-T4 with great ease. The added overhead of decoding each analog signal to its digital counterpart limits a Class I repeater to one hop. That is, the only devices you can connect off a Class I repeater are workstations, switches, bridges and routers.

A Class II repeater takes the anal og data from an incoming port and forwards it to all the other ports. This results in a faster hub that can be cascaded at the price of options like T4 connect ivity. A Class II repeater can support two hops from the switch or router to an end workstation.