Cabletron Systems STS16-20D, STS16-20R manual Switching Technology, Switch of Switches

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Switching Technology

Demand for network bandwidth continues to grow, driven by the increasing number of systems used in network-intensive applications. LAN segmentation has been the prevalent method for addressing these demands and has been further popularized by trends toward server centralization. However, the implementation costs of LAN segmentation, as well as the real performance characteristics of conventional network components, have served to limit growth of some Token Ring networks. Alternative technologies for addressing bandwidth demands present yet other inhibitors, usually relating to costs. Token Ring switching provides users with an easy, cost-effective technique for addressing these demands.

Token Ring switches, such as the SmartStack STS16-20D/STS16-20R, increase throughput between Token Ring segments by supporting simultaneous, parallel conversations. Switched connections between Token Ring segments last only for the duration of the packet—new connections can be made between different segments for the next packet.

Token Ring switches solve congestion problems caused by high-bandwidth devices and powerful applications as well as the number of users. Therefore, each of these devices—servers, for example—can be assigned its own 16 Mbps segment.

In Token Ring networks, the major bottleneck is typically the throughput to high- bandwidth devices such as servers, and between routers, bridges, and switches. An effective solution is full-duplex communication, an option for each segment connected to an SmartStack STS16-20D/STS16-20R port. Normally, Token Ring operates in half-duplex communication mode, which means stations can either receive or transmit. With full-duplex technology, two communicating stations can transmit and receive at the same time. When packets can flow in both directions simultaneously, effective Token Ring bandwidth doubles from 16 Mbps to 32 Mbps.

The SmartStack STS16-20D/STS16-20R can forward Token Ring frames among multiple, shared or dedicated Token Ring LAN segments. Using a frame forwarding technique similar to that of a multiport Token Ring transparent bridge, the switch uses Token Ring MAC addresses to forward Token Ring frames from any of its ports to any other.

Switch of Switches

The SmartStack STS16-20D/STS16-20R can be deployed in a variety of network configurations, all of which provide a significant increase in network performance. The family of Cabletron Systems Token Ring products allows users to build network systems that can transport data efficiently and scale upwards as throughput requirements increase. The SmartStack STS16-20D/STS16-20R delivers high- reliability and media flexibility. These features combine to allow the SmartStack

SmartStack STS16-20D/STS16-20R Token Ring Switches Installation and User Guide Introduction