Future-proofing Your Network Desktop Investment --------------------------------------------------------------------------- Introduction As organizations migrate mission-critical applications onto networks, the IS professionals managing them find themselves constantly struggling to ensure that today's networks don't become tomorrow's dinosaurs. With a new breed of productivity applications - distributed databases, document imaging and video teleconferencing - now pushing existing network bandwidth to their limits, the threat of obsolescence is very real. There's no underestimating the scope of the problem. Simply stated, network technologies such as Ethernet and Token Ring, originally used for file and printer sharing by a few PCs, are reaching critical mass for several reasons. Faster PCs demand faster networks. With Pentium- and RISC-class PCs expected to make up two-thirds of the computers installed by 1997 (according to market researchers at Dataquest Inc.), increased data throughput will be required just to keep up with users' applications needs. Moreover, shared-media networks such as Ethernet and Token Ring, the most widely installed LAN technologies, can't possibly support the increasingly large populations now found on LANs. With hundreds of nodes competing for the same network bandwidth, performance becomes the norm, not the exception. Nor can these overburdened networks handle the new breed of mission-critical applications companies now require to make their businesses successful. The bandwidth requirements of these applications can slow 10 Mb/s Ethernet and 16 Mb/s Token Ring throughput to a crawl. Consequently, IS managers are looking for solutions to alleviate the impending network bandwidth crisis. IS departments have begun investigating several high-speed technologies that deliver increased bandwidth to today's desktop computers, multiprocessor servers, and high-performance workstations running critical business-support applications. These technologies include ATM (Asynchronous Transfer Mode), Fiber Distributed Data Interface (FDDI), and the so-called "fast," or 100 Mb/s Ethernet, including 100Base-Tx, 100Base-Ty, and 100VG-AnyLAN. All of these technologies meet basic high-speed data-only requirements, and each offers complementary benefits and features that make it an acceptable alternative. In addition, all have their proponents, inside both the user and vendor communities, who claim their technology is the "right" one for high-speed workgroup networking. Adaptec believes that ATM is the future-proofing scalable choice for IS departments planning to migrate key workgroup-based computers to high-bandwidth networking technologies. Briefly, Adaptec believes that ATM's manageability, its scalability, its ability to use existing cabling facilities and its support of voice, data, and video applications across an enterprise make it the ideal solution for high-bandwidth server and desktop connectivity. Adaptec is aggressively marketing a complete family of ATM network interface cards (NICs) that offer all of the benefits of the company's industry-leading IOware(r) (Input/Output (I/O) solutions. This white paper defines Adaptec's position on ATM and outlines the target markets (servers, high-performance workstations, desktop workstations, Pentium/PowerPC-based, and decision-support systems) that Adaptec supports with its family of ATM IOware network interface cards. What is ATM? Unlike traditional broadband networks, ATM is a cell-switching and multiplexing technology. It combines the advantages of circuit switching - predictable delivery characteristics and guaranteed capacity - with those of packet-switching-flexibility and efficiency for intermittent traffic. This approach simplifies the delivery of time-sensitive signals, including voice and video, and is a critical requirement for multimedia applications. ATM promises to revolutionize how organizations implement and use LANs. In addition to its high-performance capabilities, ATM promises to simplify the design and management of networks, with a single architecture for desktops, backbones, and WANs. ATM is a communications technology which has "caught on" or garnered broad vendor and end user support, thanks primarily to the efforts of the 700 plus-member ATM Forum. While most other networking standards, including Ethernet, required decades of slow, gradual adoption before wide acceptance, ATM has built up a solid foundation of support in just a few years. The basic elements of ATM, dealing with packetizing voice information for use in the public switched-telephone network, were first developed at AT&T's Bell Laboratories and France Telecom's Research Center in the early to mid-1980s. Although first deployed by the telecommunications industry in wide-area networking (WAN), LAN implementations of ATM now far exceed WAN. ATM's high data rates, scalability and seamless integration into LAN-WAN environments make it an attractive option to IS organizations running out of network bandwidth or planning to implement LAN-based multimedia solutions, such as video editing, video on demand, video conferencing, or computer-based telephony. Traditional broadband network technologies such as Ethernet, FDDI and Token Ring force end users to share the network bandwidth. Because all nodes on these networks contend for bandwidth, they can be risky choices for distributed data-bases, document imaging and tomorrow's high performance applications. ATM's use of small, fixed-length 53-byte cells to carry voice, data and video signals over a series of independent, virtual channels gives it several advantages over broadband networks. First, ATM's small, fixed-length cells offer low transmission, or queuing delays (called latency) and low delay variations at high data rates. Low transmission delays are especially important in guaranteeing the on-time delivery of video or voice signals in real time. This, in turn, provides a smooth-moving image and understandable dialogue instead of herky-jerky or disjointed video and unintelligible voice. In addition, with uniform-sized cell headers, cell-switching technology can be implemented in hardware, resulting in high switching rates. Delay variation is more tightly bounded due to the predictable service rate offered by fixed-length cells. ATM is thus better positioned than Ethernet with 1,500-byte frames; FDDI with 4,500-byte frames; or Token Ring with 9,000-byte frames, to deliver voice, video, and data signals in a timely fashion. With much larger data frames, these technologies suffer from internodal latency which affects delivered voice and video effectively. Another of ATM's key features is its scalability. ATM's theoretical throughput is 9.95 Gb/s, and products supporting a wide variety of data rates, from 25.6 on the LAN to SONET OC-1 and OC-3 (51 Mb/s and 155 Mb/s, respectively) on both LAN and WAN implementations, have found their way into the marketplace. In addition, ATM's switching capabilities guarantee additive bandwidth. As long as a switch can handle the aggregate cell transfer rate, it is possible to add connections to the switch, increasing the overall total bandwidth of the system. Two Data Rates For local networking purposes, standards-setting bodies have formalized proposals establishing 155 Mb/s and 25.6 Mb/s ATM standards. Adaptec is building network interface cards that support the 155 Mb/s and 25.6 Mb/s data rates for a variety of bus architectures. Adaptec bases this decision on a number of key factors, some technical, others market driven. Adaptec believes a substantial amount of early ATM deployment into the LAN environment will come in the work-group arena. Organizations hoping to eliminate critical network bottlenecks can migrate servers and performance-oriented desktop PCs and workstations into the high-speed environments first. Client PCs are converted later from the legacy LANs to ATM as appropriate for the organization. This evolution to ATM maintains investment on the legacy infrastructure while removing key bottlenecks to the LAN. IS organizations considering migrating servers and/or high-performance desktop computers to one of the high-speed technologies should consider the tradeoffs between the various schemes before making their decision. Servers, with their heavy file I/O between a large number of individual clients, are served better by ATM's 155 Mb/s, full-duplex, connection-based transmission scheme than switched 100 Mb/s Ethernet or FDDI. At this high end, the 155 Mb/s standard, which requires using either multimode fiber-optical cable or Category 5 ("data grade") unshielded twisted-pair (UTP) wiring, gives network servers and high-performance workstations access to ATM's full capabilities. Specifically, they profit from ATM's ability to support end-to-end connections, called virtual circuits, between network nodes and create virtual LANs in physical cables. Switched 100 Mb/s Ethernet, like the FDDI and Token Ring technologies, is generally deployed as a half-duplex transmission scheme, with communication taking place only in one direction at any given moment. ATM's full-duplex capabilities let two nodes "talk" to each other simultaneously - allowing, for example, four PCs to exchange NTSC-quality video teleconferencing images with each other. The 25.6 Mb/s rate is promoted by a subgroup of the ATM Forum called the Desktop ATM25 Alliance and the physical layer subworking group. The Desktop ATM25 Alliance's goal is to produce low-cost ATM products that can compete favorably against Ethernet and Token Ring on the basis of price/performance. Most importantly, the Desktop ATM25 Alliance's 25.6 Mb/s rate enables ATM to run over Category 3 UTP wiring, which comprises about 60% of installed cabling in U.S. enterprises. For organizations with access to two pairs of Category 3 wiring, 25 Mb/s ATM offers a very cost-effective migration path to the increased data rates required for multimedia networking and multiple bi-directional video connections. Another key advantage of the 25 Mb/s approach is that it uses a variation of Token Ring's transceiver chip set. This ensures a proven technology transceiver and a quicker time-to-market, an especially vital feature in the competitive networking area. The overall cost of 25.6 Mb/s NICs is also lower than those using the 155 Mb/s standards. ATM's Other Advantages Beyond its superior data-throughput rates and scalability, ATM offers a host of other key features and benefits for IS managers chartered with planning, building and managing future networking systems. For example, because a broad variety of mission-critical applications are moving to LANs, one of the primary objectives of the typical IS manager is to strengthen network security. ATM's negotiated service, which provides end-to-end connections called virtual connections or circuits, is substantially more secure than shared-network technologies. In addition to allowing for permanent virtual circuits, each ATM communication can be established in a for-the-moment fashion, with only the nodes communicating with each other actually "seeing" the network transmissions between themselves. The switched network of ATM differs considerably from shared-network technologies such as Ethernet and FDDI. In these schemes, a transmission is broadcast over an entire network segment, readable by all of the devices on that network. This can leave key business information vulnerable to eavesdropping by so-called "promiscuous mode" adapters. These types of adapters, often found in protocol analyzers, are capable of capturing and decoding all the packets passing through a network. ATM also offers the potential to simplify the operation and management of enterprise-wide networks. An all-ATM system wouldn't require network equipment that existing internetworks use for routing and distributing the data on the network. In this environment, departmental and corporate backbone ATM switches would tie into corporate switches and large internetwork switches operated by long-distance communications providers. This architecture would leave little distinction between the devices used for connecting the workgroup, corporate backbone or WAN, thus simplifying network management. Another key advantage of ATM is its topology. At the hub of an ATM network, an ATM switch is directly connected to all network nodes. ATM interfaced desktops "home-run" wire to local switches or concentrators. This provides all the benefits of traditional star-topology technologies - point-to-point cabling plants and easier troubleshooting, that make them easier to manage and control than bus-based topologies. Why Adaptec? Adaptec's focus on designing comprehensive I/O solutions makes it the logical producer of high-performance networking interface products now and in the future. Adaptec's goal is to eliminate network bottlenecks by producing a full family of ATM network interface cards that build on the company's skills and core competencies in high performance I/O systems management. Adaptec's IOware products form a comprehensive family of I/O solutions comprised of interface cards, custom Application-Specific Integrated Circuits (ASICs), and software. These elements combine to improve overall system performance by speeding the flow of data between processors, peripherals and the network. Adaptec has a long history in pioneering a systems approach to I/O solutions. That approach, which integrates high-performance I/O hardware and intelligent I/O software, enhances and facilitates system performance, connectivity, compatibility, and interoperability. Adaptec's software component of its I/O solutions is widely accepted as the industry benchmark by operating system vendors, and its IOware products provide extensive features that enhance I/O throughput, whether across a system bus or over a network. Adaptec has been involved in every generation of PC technology, engineering I/O products compatible with major systems architectures and bus standards. With its years of experience in matching system needs with custom chip and board-level design, Adaptec has the resources and expertise to offer the quality, high-performance products that OEMs and end users demand. Adaptec engineers use the latest in sophisticated design and simulation tools to design, prototype, document, test and analyze the performance of new products on a concurrent schedule. This allows Adaptec to begin production immediately after design completion, a key in competitive markets when time-to-market and keeping costs down are vital. The company's hardware and software solutions set industry standards for "most compatible," earning it strong relationships with other industry leaders. Such widespread OEM acceptance attests to the reputation of quality and reliability that Adaptec's IOware products have earned among customers who purchase directly from Adaptec or via a worldwide network of distributors. Adaptec's ATM Product Strategy Adaptec is committed to being a world leader in the ATM network adapter marketplace by delivering a broad product family that gives its customers a price-performance advantage over competing technologies as well as other ATM vendors. At a strategic level, Adaptec's goal is to develop high-performance ATM network interface cards that offer a complete software solution, are easy to use, and interoperate with all major vendors' ATM switches, routers, concentrators, NICs, and "edge devices" required to merge existing LANs with ATM. Adaptec's ATM products ship with complete software supporting a full implementation of the ATM Forum's User-to-Network (UNI) 3.0 and 3.1 specifications, the most important of the ATM protocols. UNI covers the physical aspects of ATM connection, spelling out the copper wiring and fiber cable requirements and data rates as well as numerous protocol layers, including the adaptation layers, or AALs. AALs segment upper-layer information into cells at a transmitter, then reassemble at the receiver. AALs also form the boundaries between ATM and higher-level protocols such as IBM's Systems Network Architecture (SNA) and the Internet community's Transmission Control Protocol/Internet Protocol (TCP/IP). Adaptec's ATM software suite also offers support for transparent IP over ATM (RFC 1577), the ATM Forum's LAN emulation specification and the Interim Local Management Interface (ILMI). Support for these standards-based specifications ensures that Adaptec's ATM NICs will provide interoperability between ATM and traditional LANs such as Ethernet. Most organizations are likely to merge ATM-based systems with their traditional LANs in a heterogeneous environment, rather than abandon their existing network technologies. Therefore LAN emulation will be extremely critical to IS departments incorporating ATM into their corporate LANs. Ensuring compatibility with the ATM Forum's ILMI specifications, which provide status, configuration and control information for an ATM interface, is another critical issue. Because ILMI ensures that two different ATM devices can interface to one another, supporting the ATM Forum's ILMI standard is another key feature of Adaptec's ATM NICs. The modular, operating system-independent nature of Adaptec's software permits easy migration to new operating environments. With rapid permutations in PC operating systems, the ability to manage change smoothly is critical to remaining competitive. Additionally, the modular architecture was designed to enable aggressive implementation to new ATM Forum standards as they are approved. A hallmark of Adaptec's ATM solutions, like all of the company's IOware products, is their ease of use and guaranteed interoperability. Adaptec's interoperability labs ensure that its ATM solutions interoperate with the major vendors' ATM switches, routers, "edge" devices and NICs. Operating system and system I/O bus compatibility are equally important. Adaptec's compatibility labs leverage its IOware experience and expertise to the ATM NIC products for system level compatibility. And by developing easy-to-use graphical installation and configuration software for its ATM NICs, Adaptec delivers plug-and-play convenience, a key factor in helping IS departments keep end-user support costs in check. Adaptec's ATM adapters are also compatible with the leading network management platforms, including Hewlett-Packard's OpenView, IBM's NetView 6000 and Sun Microsystems' SunNet Manager. This allows IS support personnel to leverage their existing management platforms for use with ATM while avoiding the need to learn new management applications. With ATM, performance is paramount. Adaptec's ATM adapters provide an optimized integration of hardware, firmware and software that places low demands on the host processor. Adaptec's proprietary ASIC designs contain built-in intelligence, providing on-board segmentation and reassembly (SAR) of ATM packets and supporting full burst transfers, both important in delivering high-performance ATM throughput. Just as important, Adaptec engineers have fine-tuned the performance of Adaptec's ATM NICs through extensive laboratory analysis and evaluation with switch vendors' solutions, another critical element in providing high-bandwidth throughput. Delivering Market-driven Products As LANs have evolved, they've become increasingly sophisticated. Networks once used for just file and peripheral sharing now support complex client-server applications that play mission-critical roles in making key business decisions for their organizations. The ATM-to-the-workgroup market has mimicked the client-server model while dividing itself into two clearly defined segments: the server/high-end workstation and desktop markets. In these client-server environments, applications and hardware addressing the needs of servers must provide very different functions and features than those aimed at client PCs. Adaptec has designed the products in its broad family of high-performance and entry-level ATM NICs to meet the requirements of end users in each of these market segments. By offering market-driven products, Adaptec gives IS personnel a level of flexibility that allows them to make more intelligent decisions when migrating their systems to ATM. In the Workgroup The work-group server client, or desktop market, like its high-end counterpart, divides itself into three categories: workgroup servers for up to 50 clients, mid-range workstations and powerful decision-support systems, such as PowerPC- and Pentium-based PCs. Although each class of user in this market demands speed, the specific level of performance they require differs depending on the nature of their work. Adaptec targets its PowerDesktop NIC(tm) line at desktop workstation users who want to take advantage of 155 Mb/s ATM throughput without the costly overhead of supporting a server-level solution. Adaptec's PowerDesktop NIC ATM adapters deliver PCI and SBus connectivity at 155 Mb/s over Category 5 UTP (up to 100 meters) and multimode fiber (up to 2,000 meters with 6.26 and 125 micron fiber). Adaptec's Power Desktop NIC cards, provide on-board RAM, allowing them to support multiple virtual circuits and eight traffic profiles for maximum flexibility in network communications. Based on an Adaptec-designed ASIC that performs ATM layer protocol processing and implements an intelligent buffer-management scheme that facilitates efficient data transfer between the network and host bus, Adaptec's midrange NIC products deliver high-performance network processing while keeping demands on the host CPU low. Adaptec's PowerDesktop workstation adapters also offer a lower cost-per-seat, based on dollar-per-Mb/s, than competing high-speed technologies such as 100 Mb/s Ethernet and FDDI. By taking advantage of ATM's full-duplex capabilities, they deliver more than twice the available bandwidth of the shared-bandwidth technologies. Adaptec's ATM adapters for the decision-support market meet the requirements of end users who need fast throughput but can't justify the costs of products supporting the 155 Mb/s standard. These users have high bandwidth demands but access to two pairs of Category 3 UTP, with limited or no access to Category 5 UTP or MMF. Here, IS organizations looking to future-proof their networks with ATM require a low per-user entry cost. In this segment, Adaptec is shipping its Desktop25 NIC(tm) line of PCI-, Micro Channel Architecture (MCA)-, and SBus-ATM NICs that deliver the Desktop 25ATM Alliance's 25 Mb/s data rate over two pairs of standard telephone wire (i.e., Category 3 UTP). As with all ATM NICs, the Desktop25 NIC line supports the ATM Forum standards for LAN emulation and RFC 1577, providing mechanisms for users to connect their legacy LAN environments. Additionally, all Adaptec ATM NICs from Adaptec support UNI 3.0 and UNI 3.1 standards for PVCs (permanent virtual circuits) and SVCs (switched virtual circuits). In the Enterprise The Enterprise server market segment distinguishes itself by addressing the high-end requirements of not only servers, but high-performance workstations, such as Sun Microsystems multiprocessor SPARCstations. These kinds of systems place extraordinary demands on networking equipment, requiring high bandwidth and expanded communications services. Servers in particular need high-performance I/O subsystems that react quickly and efficiently to the requests of multiple clients. Slowdowns in network I/O at the server can cause bottlenecks that affect an organization's ability to make decisions. High-end workstations make similar demands on networks: with multiple processors moving large image or CAD files over a network, they can devour huge amounts of bandwidth. Servers and high-end workstations thus require ATM network interface cards with high-end 155 Mb/s throughput, for example, and support for a large number of virtual circuits, with enough memory to deliver exceedingly fast network-to-host I/O. In this high-end market, Adaptec will produce ATM NICs for the PCI, SBus and EISA buses that support 155 Mb/s throughput over Category 5 copper wire and multimode fiber. These single-slot NICs support an extended number of virtual circuits, which are required to meet the intensive I/O demands placed on servers and high-performance workstations. Adaptec's NICs for this market comply with all of the ATM Forum's specifications. In particular, they'll meet AAL 5 conformance requirements with pass-through capability for non-AAL 5 traffic. In Summary ATM, one of several high-speed networking technologies emerging in the marketplace, offers IS professionals a compelling migration path to evolve from their existing shared-bandwidth local-area networks. ATM's packet-switching, cell-transfer technique promises to revolutionize how IS professionals design and implement LANs by delivering scalable, high-speed (155 Mb/s and 25 Mb/s) full-duplex data transmission and bandwidth on demand. ATM is the logical choice for organizations running mission-critical applications, including distributed databases and medical imagery programs, on networks running out of bandwidth. Adaptec, as a leader in I/O technology, is committed to being the world leader in the ATM network interface card market by delivering a broad range of high-performance, cost-effective ATM NICs for the server, high-end workstation and desktop computing environments. Adaptec's ATM NICs, as part of the company's successful IOware family of peripheral connectivity solutions, provide IS professionals the tools they need to "future-proof" their networks. Part Number: W850089-012 --------------------------------------------------------------------------- Glossary of ATM Terms AAL ATM Adaptation Layer. One of three layers of the ATM protocol reference model. It translates incoming data into ATM cell payloads and translates outgoing cells into format readable by the higher layers. Five AALs have been defined: AAL1 and AAL2 handle isochronous traffic, such as voice and video, while AAL3/4 and AAL5 pertain to data communications through the segmentation and reassembly of packets. ATM Asynchronous Transfer Mode. A form of data transmission based on fixed-length packets, called cells, that can carry data, voice and video at high speeds. This technology is designed to combine the benefits of switching technology with those of packet switching. ATM is defined by ITU-T ATM Forum specifications. ATM Forum A 700-member vendor and end-user consortium created to promote standards and interoperability for ATM products. CCITT Consultative Committee for International Telegraph and Telephone. An international organization that develops communications standards. The name was recently changed to the International Telecommunications Union (ITU). Desktop ATM25 Alliance An ATM Forum subgroup formed to promote international standards for 25 Mb/s ATM products. Ethernet An industry-standard (Project 802.3 of the IEEE) that specifies protocols for connection and transmission in local-area networks. Ethernet operates at 10 Mb/s and now, 100Mb/s. FDDI Fiber Distributed Data Interface. An American National Standards Institute (ANSI) standard for a 100 Mb/s token-passing ring based on fiber-optic transmission media. IEEE Institute of Electrical and Electronics Engineers. A professional organization that defines network standards, such as Ethernet. Internetwork Two or more local-area networks connected by bridges and/or routers. IP Internet Protocol. Associated with TCP, a set of communications protocols developed to internetwork dissimilar systems. TCP controls the transfer of data while Iable alternative. In addition, all have their proponents, inside both the user and vendor communities, who claim their technology is the "right" one for high-speed workgroup networking. IPX Internet Packet eXchange. A Novell NetWare communications protocol used to route messages from one node to another. Novell's version of IP. OC-n Optical Carrier n. Optical signal standards. The "n" indicates the level where the respective data rate is exactly "n" times the first level, OC-1. OC-1 has a data rate of 51.84 Mb/s. OC-3 is thus three times OC-1, or 155.52 Mb/s. PCI Peripheral Component Interconnect. A type of high-speed computer bus. PHY Short for Physical Layer. The network protocol layer that passes data from the media to the ATM layer, and vice-versa. PMD Physical (layer) Media Dependent. Refers to the part of a network interface card's design that must interface with (and is therefore dependent on) the chosen transmission medium (Unshielded Twisted Pair or Multi Mode Fiber). PVC Permanent Virtual Circuit. A logical (rather than physical) connection between end points established by an administrator, which stays intact until manually torn down. See SVC. Router A device that connects LAN segments to other LANs or WANs. SAR Segmentation And Reassembly. Converts between the adaptation layer and the ATM layer (e.g. AAL5 frame to ATM cells). Server A computer on a network that services other nodes. Also called a back end or engine. SONET Synchronous Optical NETwork. A U.S. standard for optical digital transmission at hierarchical rates from 155 Mb/s to 2.5 Gb/s and beyond. SVC Switched Virtual Circuit. A logical (not physical) connection between end points established by the ATM network on demand after receiving a connection request from the source, which it transmits using the UNI signaling protocol. See PVC. TCP Transmission Control Protocol. See IP. Token Ring An industry standard (Project 802.5 of the IEEE) that specifies protocols for connection and transmission in local area networks. Token Ring transmits at 4 Mb/s or 16 Mb/s. UNI User-to-Network Interface. The interface between a user's device and an ATM switch, defined as the physical, ATM and higher layer (e.g., signalling).