Advanced Full Duplex Ethernet Solution Twice the Bandwidth on Your Current Ethernet for 20% of the Cost As heavily loaded networks become increasingly common, MIS professionals are seeking solutions which increase network bandwidth and reduce network overload. Believing that the performance potential of Ethernet has been exhausted, many MIS professionals look to expensive solutions such as FDDI and Fast Ethernet to provide relief from poor network response times. But there is significantly more performance to gain from existing Ethernet--at a fraction of the cost of more expensive solutions. Full duplex Ethernet (FDE) is an evolutionary new technology available today which more than doubles existing Ethernet cable bandwidth far less expensively than other alternatives. FDE has already become a new standard through the combined efforts of companies such as Cogent, IBM, Kalpana, Compaq, Cabletron Systems, and SynOptics. Anticipated to quickly become the most popular and cost effective way of increasing performance in Ethernet networks, FDE enables data in 10BASE-T twisted pair cable networks to be simultaneously transmitted and received on different wire pairs. This means that network resources can be accessed twice as fast as traditional half duplex Ethernet which is limited to either transmitting or receiving data. Whereas the maximum throughput rate of half duplex Ethernet is only 10 MBits/sec., FDE has a maximum throughput rate of 20 MBits/sec. Because FDE is fully compatible with IEEE 802.3 standards and uses existing 10BASE-T cabling, companies can preserve their investment in existing Ethernet hardware. To take advantage of this breakthrough in Ethernet, Cogent has introduced full duplex capability in its 32-bit EM945 EISA FDE Ethernet LAN adapter. The combination of FDE and Cogent's own Predictive Pipelining (tm) (U.S. pat. pend.) technology in EM945 EISA FDE dramatically increases system performance by minimizing bottlenecks at critical points in the network: the cable, adapter, and driver. Full Duplex and Predictive Pipelining: The Ultimate Performance Combination Improved Workstation Response Although EM945 EISA FDE is designed for network servers which can handle multiple processes simultaneously, its performance benefits reverberate throughout the entire network. Workstation response times in FDE networks are extremely fast for several reasons. First of all, because FDE servers can handle both receive and transmit requests simultaneously, workstation requests can be serviced more quickly. For example, an FDE server can communicate with two workstations at the same time by transmitting to one and receiving data from the other. Servers in traditional Ethernet networks can only transmit or receive at a time, so workstations must wait until the server finishes receiving incoming transmissions before they get a response. Switched Ethernet Removes All Collisions Another benefit of FDE is that it provides a collision-free environment. Unlike traditional Ethernet which must contend with frequent collisions on the cable, FDE switching enables private conversations to occur between computers on the network without collisions. Therefore, in FDE networks, workstations and servers can take advantage of full cable bandwidth of up to 20 MBits/sec. throughput. Maximum Efficiency Many MIS professionals do not realize that in addition to increased cable bandwidth, system performance is dependent upon the efficiency of the network driver software and the Ethernet LAN adapter_the network driver and LAN adapter must both be able to "keep up with the cable." Recognizing that optimal Ethernet performance requires a system solution, Cogent designed its EM945 EISA FDE adapter with both FDE and Predictive Pipelining. An innovative new technology, Predictive Pipelining eliminates major design flaws in traditional Ethernet adapters: bottlenecks at both the hardware and software levels which contribute to slow response times. Implemented in both hardware and software, Predictive Pipelining transparently establishes a virtual message connection between eMASTER+ adapters and overlaps transfers for maximum speed and efficiency. Predictive Pipelining also dramatically reduces processing overhead by handling whole messages instead of just single packets. With FDE and Predictive Pipelining, the efficiency of EM945 EISA FDE clearly surpasses any other FDE adapter on the market. The EM945 EISA FDE is the only FDE adapter which has attacked the problem of bottlenecks at not only the cable, but also the adapter and network driver levels. Scalable Architecture Increases Bandwidth Before they turned to switched Ethernet, network administrators increased network bandwidth by using multiple network adapters in a single server. Because each server adapter can handle multiple workstation adapters at full cable bandwidth, scalable architecture still makes sense in switched Ethernet environments such as FDE networks. Network server resources can be fully utilized by using a third-party load-balancing software program such as Balance NLM from Network Specialists, Inc. Load balancing ensures that each adapter installed in a server handles approximately the same amount of network traffic. As more adapters are added in the server, network bandwidth increases linearly resulting in significant performance advantages. Compatibility with Your Existing Installation FDE is an evolutionary technology, not a revolutionary one. Revolutionary technologies, such as FDDI or Fast Ethernet, represent radically new innovations which require an entirely different way of thinking. Whereas revolutionary technology can be intimidating, difficult to adopt, and costly, evolutionary technology represents a more gradual progression towards innovation. FDE builds on existing technology and provides a "kinder and gentler" solution while doubling network bandwidth. Unlike other solutions, FDE is compatible with existing systems and does not require new wiring infrastructure. The performance benefits of FDE can be realized without installing costly wiring systems because FDE uses existing 10BASE-T wiring. Networks can also take advantage of FDE without losing current investments in standard Ethernet LAN adapters. FDE adapters are generally only used in servers so FDE and standard adapters can be used together in the same network. Although FDE adapters require FDE-capable switching hubs, such as the EtherSwitchV from Kalpana or the model 3328 Ethernet Switching Engine from SynOptics, these solutions are comparable in price to existing solutions for traditional switched 10BASE-T Ethernet. The compatibility of existing Ethernet adapters and FDE adapters makes migration to FDE networks even easier and risk-free. More Bandwidth, Less Money FDE's compatibility with existing 10BASE-T networks means that the cost of upgrading to a full duplex configuration is dramatically less per dollar of throughput than other solutions. An FDE network can give twice the throughput of half duplex networks using standard twisted pair cable, LAN adapters, and 10BASE-T hubs. In contrast, upgrading to an FDDI or Fast Ethernet configuration requires expensive new cabling and rewiring, new hubs, LAN adapters, and so on. If each Mbit/sec. of throughput is measured in dollars, FDE is money in the bank. Full Duplex Adapters Explained Take a look at your network's 10BASE-T twisted pair cabling. It is composed of two wire pairs which transmit data in either the half duplex mode or full duplex mode. Standard Ethernet networks use half duplex technology which is limited to either sending or receiving data on one wire pair at a time. Therefore, while one wire pair may be sending data, the other wire pair is waiting unused until it can receive data. Besides underutilizing the cable, standard half duplex technology is subject to collisions which sharply decrease performance in loaded networks. In half duplex Ethernet, all computers in a network must share the same cable. If more than one computer attempts to use the cable at the same time, their data collides and the computers must back off the cable and try to transmit again_wasting valuable time. Using the same standard 10BASE-T twisted pair cable as half duplex Ethernet, Cogent's new full duplex technology lets data travel on two wire pairs simultaneously. Because one wire pair can send data at the same time that the other pair is receiving data, all cable resources can be fully utilized. Like half duplex, FDE requires a hub or switch to multiplex transmissions. However, FDE switches do more. They negotiate communication between full duplex and half duplex computers and establish direct communication paths between computers. The ability to have private conversations between computers in FDE networks not only eliminates data collisions, it also allocates a dedicated line which makes available the full bandwidth of the cable. With FDE switches, computers do not have to share the cable with other computers, which results in significant performance advantages. Cogent's FDE adapters have been designed and tested for compatibility with switches from vendors such as Kalpana and SynOptics.