Product Survey: High-Speed Networking
Compiled by Ralph Barker
While the Internet, intranets, extranets, and the World Wide Web have certainly added new dimensions to computing, these trends have also placed a considerable strain on network bandwidths. If you have not yet started to implement some form of high-speed networking within the infrastructure of your network as a way of satisfying the bandwidth needs of your users, now is a great time to consider doing so. Although the range of technology choices may be confusing, the competition between products and technologies also drives the prices down. As a result, adding high-speed elements to your network has never been more affordable. In this Sys Admin Product Survey we examine some of the high-speed alternatives that fit best in traditional UNIX networks, 100Mbps and faster Ethernet products, to help you plan and purchase upgrades for your network. The Network Deli Unless you have been hiding in the machine room, you are likely aware of the variety of choices for high-speed networks - much like walking into a delicatessen in New York City. While FDDI was previously the backbone of choice (assuming your organization could afford the relatively high cost associated with the technology), several new technologies that provide viable alternatives to FDDI have appeared and gained a degree of maturity within the marketplace. Fast Ethernet, which provides a theoretical bandwidth of 100Mbps and is compatible with existing 10Mbps Ethernet networks, has largely succeeded against the competing (and arguably superior) 100VG-AnyLAN technology from Hewlett Packard. ATM, in both 25Mbps and 155Mbps variations, is still trying to get a toehold in machine rooms and on desktops, but is not having great success. Meanwhile, Gigabit Ethernet has also come on the scene, providing 1000Mbps speed and compatibility with existing Ethernet technologies. Early Gigabit Ethernet implementations were shown at the Spring 1996 NetWorld+Interop trade show as proofs of concept. Surprisingly, however, real Gigabit Ethernet products were being demonstrated just a year later at the Spring 1997 NetWorld+Interop show, and should be shipping by the time you read this. Additionally, competing Fibre Channel products were also being demonstrated at this last show and are currently shipping. There is also some promising activity in the area of 655Mbps ATM, and some interesting work being done in the area of LAN emulation on ATM. Both Fibre Channel and ATM are beyond the scope of this article, however. All of this boils down to one thing for systems and network administrators - technology choices with an acceptable degree of stability. Major network vendors have been shipping Fast Ethernet products long enough to establish a high degree of interoperability, thus allowing you to mix and match products from different vendors with a fair amount of confidence. Gigabit Ethernet and Fibre Channel products are, of course, still in their infancy and represent greater risk at this point. If you need that level of speed at your backbone, however, you now have real choices. In all but the most sophisticated user-requirement scenarios, Fast Ethernet, Gigabit Ethernet, Fibre Channel, and high-speed ATM products are aimed at the server and backbone levels within typical network topologies. At present, few users need 100Mbps or more to their desktops, but that may change in the coming years. Most network experts are currently recommending a mix of Ethernet (and other technology) speeds, using a combination of multi-speed hubs and switches, along with multi-protocol routers and bridges, to form the fabric of your network. Exactly how you mix and match these products depends on how you need to segment your LAN and what your particular combination of user requirements happens to be. Layered on top of the hierarchy of hubs, swithces, routers, and bridges is the issue of management. Both managed and unmanaged hub and switch products are available, and those that include management features offer various combinations of SNMP and RMON support. Some products that include management features also provide the ability to create virtual LANS or VLANs between designated nodes. While VLANs add considerably to the complexity of management, the feature also provides a useful and highly flexible dimension to network segmenting. Rudimentary component configuration is often provided by means of a serial port on the hub or switch, in that the unit is not addressable across the network until basic configuration parameters (IP address and so forth) have been set. Once the basic configuration is defined, management of the unit usually shifts to telnet connections and the use of more sophisticated management software running on a host or network management workstation. Another feature that may be of interest is support for the Spanning Tree Protocol. Defined in IEEE 802.1d, Spanning Tree adds a level of fault tolerance to networks by allowing two or more redundant connections between network segments. The protocol chooses which of the redundant physical paths to use at any given time, disabling others in the process. Should that link fail, however, the protocol chooses an alternate path to maintain the connection. Although this adds another element of complexity to the network configuration and management, the extra effort may be repaid by the benefits of fault tolerance. Planning and Resources A typical network topology resulting from the additional high-speed choices might include a Gigabit Ethernet, Fast Ethernet, or Fibre Channel backbone appropriately interconnected to a series of Fast Ethernet switches, each of which, in turn, serves a hierarchy of 10/100 Ethernet switches and hubs. The usual plan in such a network is to provide high-speed connections to and between top-level servers and slower-speed connections to individual user desktops. The trick to properly planning the layout is to know the traffic levels of your network well enough to locate the so-called fat pipes where they are needed, and conventional Ethernet connections to desktops and/or servers that do not require the higher bandwidth. Most of the major equipment vendors can provide helpful documentation that will assist in your planning process. Some of this documentation is written to an audience of technical managers and is thus intended to provide an overview of the concepts without getting into installation-level details. Additionally, much of this type of documentation presents the information from the perspective of that particular vendor's equipment design. By mentally filtering out the marketing messages, however, you can gain considerable insight into both the general process and how that vendor approaches the technical requirements. Once you are close to making purchase decisions, you may also want to request copies of the technical manuals for the candidate gear in order to get a more detailed understanding of the administrative issues that you will be facing during installation and configuration. How to Use the Survey There are two primary elements to this survey: the product features table that lists features for qualifying products from vendors that responded to our information request, and the vendor contact list. The vendor list is, in turn, organized in two sections. One section provides information for vendors that responded to our information request. The other section lists contact information for other vendors that have products in these categories but failed to respond to our requests for information. You can use the feature list to generate a rough profile of your requirements. You might, for example, make a copy of only the feature column on the page without the product information. Then, go through that list to determine the features that are important to you. Armed with that information, you can then scan the list for products that match your feature set, and contact the corresponding vendors for more detailed product information. In addition to the technical specifications outlined in the accompanying feature chart, here are a few practical elements you should also consider. Cooling: Most of the units are fan-cooled, but the vendor specifications tend to omit information about the noise level of their unit's fans. If the unit is going to be placed in a machine room or wiring closet, fan noise is not an issue. For units destined for placement in work area, however, fan noise can be a major issue. Flexibility: Consider how the new units will integrate into your existing network. Does the high-speed unit you are considering provide one or more 10Base-T ports for direct integration with existing networks? Or, does that model require a separate unit to provide that connectivity? Futures: Although the implementation of the expanded numbering scheme provided by IPv6 is still a way off, planning ahead may save both money and headaches. Does the unit you are considering currently support IPv6? If not (currently, most do not), what is the vendor's position on IPv6 upgrades and what is their schedule for implementation. What is not clear in the feature table is that the products of each vendor follow that vendor's design philosophy and strategy. Although the end result is the same on any network, getting packets from one point to another, different design philosophies may provide a better fit with your requirements. Once you start collecting detailed product information from the candidate vendors, their respective design approaches will become clear. Some vendors, for example, focus their products on the requirements of smaller sites. Such vendors tend to have products that are easier to install and provide fewer management features. In contrast, the product lines of other vendors may concentrate on the requirements of large enterprise sites, and may include far greater flexibility and configurability, along with a much richer set of management functions. In the process of selecting upgrade products for your network, don't forget to plan for the future. Look for products that will both fulfill your current requirements and retain their value as part of a future network topology. Product Evaluations While no test scheme is likely to provide sufficient information to satisfy the variations in site requirements of all our readers, we wanted to get a firsthand look at some of the features being incorporated into the currently available products. For that reason, we invited all of the vendors to submit products in the various categories represented in the accompanying feature table. The following sections provide an overview of each of the products we tested, along with summary conclusions that may assist you in selecting products for your environment. Our test configuration included a Sun SPARCstation 5, upgraded with a Ross Technologies dual-HyperSPARC (166MHz) motherboard and a SunSwift 10/100 SBUS Ethernet adapter from Sun Microsystems, and a Tatung U2200 dual-CPU (200MHz) UltraSPARC workstation, along with other workstations and PCs in our existing network. Products are listed in vendor-alphabetical sequence.
Vendor: Compaq Computer Corp. Product: Netelligent 2524/2624 100Base-T Repeater Product Category: Stackable Hub
Compaq's Netelligent 100Base-T repeaters (hubs) are available in 12-port (models 3512 and 3612) and 24-port configurations (models 2524 and 2624). The models having a 5 as the second digit in the model number are unmanaged, while the versions with 6 as the second digit are managing hubs. The managing hub acts as the logical base of the stack, with multiple unmanaged hubs being added to the stack's maximum capacity (three in the case of the 2524/2624, or 72 ports; five in the case of 3512/3612, or 60 ports). The managing hubs also have an RS-232 port (DB-9) for configuration and management, plus a slot for a Compaq Smart Uplink Module (SUM). The 2524/2624 stack provides a single backplane segment, whereas the 3512/3612 stack are segmentable on a per-unit basis with a maximum of three segments per stack. Twisted pair and fiber (both ST and SC interfaces) SUMs are available as options. Optional redundant power supplies are available for the 3512/3612 models, while the 2524/2624 models have only a single power supply. The Compaq units are Class 1 repeaters, meaning that standard 100Base-T cable length and repeater count rules would typically apply. By using a special buffer to isolate collisions, however, SUMs restart length and repeater counts each time an uplink is made through one of these units. According to Compaq documentation the SUM is up to 20 times faster than a Fast Ethernet bridge, thus allowing multiple SUM uplinks without significant reduction in overall throughput. Using 100Base-FX SUMs provides a maximum distance between Compaq repeaters of 412m (1352 feet). Otherwise, the standard 100m distance limitation applies to both the repeater-to-endpoint and repeater-to-repeater distances. If a SUM has not been installed, uplinks can also be connected to the standard ports on the unit, using crossover 100Base-TX cables, but the distance and repeater count rules apply in such a configuration. Installation Installing the Netelligent repeaters is simple and straightforward. Our test configuration included one 2624 managing repeater and one 2524 unit. The units can be stacked on a desktop or equipment shelf, or placed in a rack using the brackets that are supplied with each repeater. To connect the backplanes of the units, you simply connect the supplied ribbon cable to the appropriate ports. Then, attach the shielded power cables, first to the units and then to an electrical outlet. You configure the stack initially by connecting a terminal, PC, or workstation to the serial port on the managing repeater. The repeater's serial port cycles through various connection speeds at ten second intervals. Once you see a recognizable string, you type in "vt100" to sync the speeds of the ports. The repeater then prompts for a password and displays the main menu once you enter the correct password. Once you have completed the initial configuration of the repeater, you can continue to manage it via the serial port or telnet in across the network. As a security precaution, the unit does not allow a login via telnet if a session is active on the serial port, however. Management Although you can perform basic stack management via the vt100 terminal interface provided on the managing repeater's serial port, two additional software components are provided for more in-depth management functions. Netelligent Management Software (Win95 or NT) r1.1.2 provides stack management via SNMP, MIB browsing, and traps. This software can also run under Compaq's Insight Manager, supplied on the Compaq Management CD, r3.20A, which extends the management functionality of the management console to Compaq servers and desktop clients. The supplied software provides a graphical interface to management functionality and is the recommended method of managing the stack. The management menu structure available through the serial port provides basic configuration screens, along with various port statistics, including readable frames and octets, collisions, and alignment errors. Evaluation Compaq's documentation for the Netelligent hubs is thorough and easy to understand, making both configuration and operation quite simple. The Smart Uplink module allows extended distances when connecting to other Compaq hubs with Smart Uplink modules. Both the terminal interface menu and the supplemental management software provide good management capabilities, particularly if you have Compaq servers and are using Insight Manager. The fans in the Netelligent hubs are quiet enough that the units could be comfortably used in a work area.
Vendor: Hewlett Packard Product: HP AdvanceStack Switch 2000 Product Category: Fast Ethernet Switch
The HP AdvanceStack Switch 2000 is at the high end of HP's AdvanceStack line and provides a modular approach to Layer 3 switching at the departmental or backbone level. The unit has six module bays that can accommodate various hot-swapable 10Mbps or 100Mbps interface modules, including 10Base-T, 10Base-FL, 100Base-T, 100VG, FDDI and ATM, all of which connect to the unit's 1Gbps backplane. Key features include port-based VLAN support, protocol filtering, spanning-tree (IEEE 802.1d) support with multiple VLANs, and dynamic bandwidth allocation with HP's Multimedia Traffic Control for multimedia applications. Installation Installation of the HP AdvanceStack Switch 2000 generally follows the pattern of other similar devices. If you have additional port modules that were not factory installed, install them first. Then connect the power cord and allow the switch to complete its self-test procedures. If no faults are found during self-test, you can proceed with the configuration. To do so, connect a terminal or PC running terminal emulation software to the serial port on the front of the switch. Once the communications rates are in sync, the switch will display the main menu. In keeping with the advanced features of the switch, the configuration submenu has 16 possible selections. Move the cursor to the "Internet (IP) Service" item and press the Enter key. This brings up the IP configuration screen so you can set the IP address, subnet mask, and gateway address for the switch. You can also configure the "timep" protocol parameters on this screen if you have a timep server on the network. You can then move back to the main menu and configure other features of the switch, such as port characteristics, VLAN definitions, and so forth. Management While the terminal interface menus provide extensive management capabilities, the AdvanceStack switch can also be managed via SNMP and through HP's AdvanceStack Assistant for OpenView-UNIX. At the time of our testing the AdvanceStack Assistant was only available for HP-UX, however. Evaluation The first thing that you'll notice about the AdvanceStack 2000 is the fan noise, or rather the lack of it. Although the seven-inch tall unit has two large fans, it is whisper quiet - a considerable advantage if the unit is planned for desktop use in a user environment. Although four-port MDI-X 10Base-T modules are available to provide downlinks to existing 10Base-T hubs and switches, our test configuration was equipped with only 100Base-T port modules. Any of the AdvanceStack 2000 100Base-T ports can be used for 100Mbps downlinks, however (using a crossover cable). Thus, in examining interoperability of the AdvanceStack 2000 with other equipment, we connected the HP unit to the Matrox Shark Switch 8/2 to provide the link to our existing network. HP's documentation for this unit is also worthy of special mention. Of the units we tested, the AdvanceStack 2000 documentation was the most thorough. HP's AdvanceStack Switch 2000 was the most sophisticated of the units we evaluated and the most flexible as to its configuration. In addition to VLAN and Spanning Tree support, the AdvanceStack 2000 can also be configured to support IP Multicast (IGMP) for multimedia applications. When IGMP is configured, the AdvanceStack 2000 will automatically assume the role of the IGMP querier if a multicast router/querier is not detected on the network. In either case, the AdvanceStack 2000 examines IGMP traffic to learn which of its ports are connected to multicast servers and clients, and directs IGMP traffic accordingly, thereby saving bandwidth on ports that are not part of the multicast group.
Vendor: Linksys Product: Stackable EtherFast 100Base-TX 12 Port Hub Product Category: Stackable Fast Ethernet Hub
The Linksys Stackable EtherFast 100Base-TX 12 Port Hub provides a simple, unmanaged solution for Fast Ethernet networks. Up to six units can be stacked in a shared-bandwidth configuration. Any port on the base unit in the stack can then be connected to a 10Base-T hub through a 10/100 switch, providing connectivity to existing 10Mbps networks. A stack uplink cable is provided with each unit, along with mounting hardware that allows the unit to be mounted in a rack. All Linksys Stackable EtherFast 100Base-TX 12 Port Hubs have two backplane connectors on the rear panel - an uplink port and a downlink port. Thus, units can be placed anywhere within a stack by simply connecting each succeeding uplink port to the downlink port of the next unit in the stack. Each unit in the stack must have a unique stack ID, which is set via DIP switches on the back of each unit. Standard straight-through Cat 5 RJ-45 cables are used to connect network endpoints to the hub and crossover cables are required to connect the stack to other hubs or switches. A specially configured RJ-45 uplink port is not provided - any of the ports can be used for that purpose by using a crossover cable. Installation Due to the simplicity of the unit, installation is essentially limited to connecting power and Ethernet cables. If multiple units are used in a stack, backplane cables are connected on the rear panel and the respective hub IDs are set via DIP switches. All very simple and straightforward, and explained well in the unit's 14-page instruction booklet. Management - none Evaluation The LinkSys Stackable EtherFast 100Base-TX 12 Port Hub provides good expandability for simple, unmanaged networks. We encountered no difficulties with the unit during the evaluation. The noise level from the EtherFast's fan, however, may be too high for most work areas, making placement in a machine room or wiring closet the better choice.
Vendor: Matrox Networks Product: Matrox Shark Switch 8/2 Product Category: 10/100 Ethernet Switch
While the Matrox Networks product line includes various rack-mountable hubs and switches, PC-server NICs and switches, the Matrox Shark Switch 8/2 is a compact (2.25"H x 6.55"W x 7.08" D), unmanaged desktop switch that provides eight 10Mbps ports and two ports that can be configured as either 10Base-T or 100Base-TX links. A 100Base-FX fiber uplink is optional. The unit's store and forward architecture ensures reliability, while its built-in packet buffer is designed to improve performance. Powered by a small AC/DC power supply, the unit does not require fan-assisted cooling, making it convenient for noise-sensitive office environments. The switch supports up to 8,192 MAC addresses, which provides considerable flexibility in how the unit is used within a network topology. For example, some or all of the switched 10Mbps ports might be connected to workgroup hubs and the two 10/100 ports configured as 100Base-TX connections to servers. Configuration of the two 10/100 ports is accomplished via internal DIP switches. Either or both of the 10/100 ports can also be used as uplinks to other hubs or switches by using crossover cables. Each of the ports can be configured as either half- or full-duplex via internal DIP switches, as well, providing considerable flexibility for a unit of this size. Installation Documentation for the Matrox Shark Switch 8/2 is a simple instruction sheet that describes basic operations and the DIP switch configurations. The default settings of the DIP switches provide half-duplex operations on all ports and configure the two 10/100 ports at 100Mbps. If the default settings are consistent with your requirements, installation procedures are reduced to simply plugging in the unit's power supply and connecting uplink and end-point cables. Management - none Evaluation Although the Matrox Shark Switch 8/2 is very small, it supports up to 8,192 MAC addresses, providing considerable flexibility in operation. The small size of the Matrox Shark and the absence of a cooling fan also make it convenient for placement in workgroup areas where noise might be a problem. The configurability of the two uplink ports allows the unit to be used as an integration link between existing 10Base-T networks and Fast Ethernet segments. Of the units we tested, the Matrox Shark was definitely the handiest.
Vendor: Standard Microsystems Corp. (SMC) Product: TigerSwitch 8, model SMC6508TT Product Category: 10Base-T Switch with 100Mbps uplinks
The three members of SMC's TigerSwitch 8 family of 10Mbps Ethernet switches each provide eight switched 10Base-T ports, but with different Fast Ethernet front-ends. The model we tested included two 100Base-TX ports, while the SMC6508TF combines one 100Base-TX port with a 100Base-FX port for fiber uplinks. The SMC6508T8T incorporates the same eight-port 10Base-T switch, a 100Base-TX uplink, and an integrated eight-port 100Base-TX Class II hub. Each of the models includes a DB-9 serial port for out-of-band console management, and can also be managed in-band via Telnet or any SNMP-based network manager. The back panel of the TigerSwitch includes a DC input connector for SMC's optional Redundant Power Unit - an external power supply that can provide power to the switch in the event its internal power supply fails. All of the TigerSwitch models employ a buffered store-and-forward architecture that performs error checking to prevent bad packets from being propagated across the network. Each port on the TigerSwitch has a link indicator LED, but traffic status is displayed on a shared set of LEDs and a front-panel button is used to select the port for which full status information is desired. Installation Installation of the TigerSwitch 8 is quite simple. After plugging in the AC power, connect a terminal or PC to the console port. The configuration main menu provides selections for setting the primary switch parameters (IP address, etc.), port configurations, statistics, and utilities. The "Switch Configuration" selection allows you to set the unit's IP and SNMP configurations, set up Spanning Tree parameters, address aging, and port mirroring. The TigerSwitch 8 MIB is provided on a diskette for use with SNMP management. Management Initial configuration of the TigerSwitch is accomplished via the front-panel serial port, similar to most managed hubs and switches. The interface provided is a conventional character-based menu structure that provides both configuration and various management functions. After the IP address of the switch is configured, basic management can be performed via telnet. Common statistics are available through the menu structure, as well. Software updates for the switch can be accomplished either via TFTP or the serial console port. Additionally, the TigerSwitch 8 provides port mirroring, which can be used for full RMON support via an external, third-party RMON probe or for traffic analysis with a network sniffer. Evaluation We encountered no problems with the TigerSwitch 8 during our testing, and found the unit's terminal interface management functions to be convenient for a workgroup-level switch. The additional SNMP and RMON management functionality allows the unit to be integrated into a more complex environment with external SNMP and RMON management stations. The TigerSwitch 8 model we tested (eight switched 10Base-T ports and two 100Base-T uplinks) would be an excellent way to add switched 10Base-T bandwidth to a workgroup that has outgrown a shared segment. A machine room or wiring closet would be our suggestion for placement, however, as the fan noise of the TigerSwitch 8 is moderate.
The vendor information listed below is, to the best of our knowledge, accurate and complete. However, not all vendors responded to our efforts to verify their contact information. The publisher assumes no liability for errors or ommissions. Vendors Listed in Tables
Asante Technologies, Inc.
Bay Networks, Inc.
Canary Communications, Inc.
Compaq Computer Corp.
CrossComm Corp.
D-Link Systems, Inc.
Farallon Communications, Inc.
FastLan Solutions, Inc.
Lantronix
Linksys
Matrox Electronic Systems, Ltd.
OfficeNet Inc.
PlainTree Systems, Inc.
SilCom Technology, Inc.
South Hills Datacomm
Standard Microsystems Corp. (SMC)
Sun Microsystems, Inc.
SVEC Computer Corp.
SysKonnect, Inc.
TRENDware International, Inc.
Other Network Vendors
Acclaim Communications
Accton Technology Corp.
AccuLan Corp.
Adaptec, Inc.
Addtron Technology Co., Ltd.
ALFA, Inc.
Allied Telesyn International Corp.
Black Box Corp.
Cisco Systems, Inc.
CNet Technology, Inc.
Compex, Inc.
Danpex Corp.
Digital Equipment Corp. (DEC)
E-Tech Research, Inc.
FORE Systems, Inc.
Garrett Communications, Inc.
Hitachi Computer Products, Inc.
IBM
(Personal Computer Enhancement Division)
Intellicom, Inc.
Invisible Software, Inc.
Kingston Technology Corp.
KTI-Katron Technologies
LANart Corp.
Lite-On Communications, Inc.
Longshine Microsystems, Inc.
Madge Networks, Inc.
Microdyne Corp.
NBase Communications
Network Peripherals, Inc.
Proteon, Inc.
Retix
Sonic Systems, Inc.
TCL, Inc.
Transition Networks, Inc.
Whittaker Xyplex
Xedia Corp.
About the AuthorRalph Barker is the Senior Editor for Sys Admin.
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