Olicom manual Switch Theory of Operation, How the CrossFire 8600 and the CrossFire 8605 Works

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2. Switch Theory of Operation

This chapter explains how the CrossFire 8600 Token-Ring Switch and/or the CrossFire 8605 Token-Ring Fiber Switch improve network performance.

The topics of this chapter are presented under the following titles:

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“How the CrossFire 8600 and the CrossFire 8605 Works”, starting on page 17.

“Benefits of the CrossFire 8600 and the CrossFire 8605”, starting on page 32.

How the CrossFire 8600 and the CrossFire 8605 Works

The CrossFire 8600 and the CrossFire 8605 are both IEEE 802.5-compliant devices designed to boost throughput on Token-Ring networks. They operate as a Media Access Control (MAC)-layer device that is protocol independent.

This chapter describes how the switch operates as a single stand-alone unit. The switch contains the following main elements, as listed below:

•Switching Bus—the architecture of the switch centers around the AXIS bus, a 520 Mbps switching fabric through which all switched ports communicate. The AXIS bus is a partially asynchronous time division multiplexed bus used for switching packets between heterogeneous LAN modules.

•Token-Ring Ports—each port can attach to a classical Token-Ring segment or to a dedicated station. Now users running basic applications are able to share bandwidth, and users running bandwidth-intensive applications can receive their own dedicated 16 Mbps port. Each dedicated port can also be set up in full-duplex communication mode, so that each 16 Mbps port doubles to 32 Mbps.

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Expansion Modules—each switch supports two expansion modules. These modules include RJ-45 or fiber ports to provide up to eight additional 16 Mbps ports, or high-speed connections such as 155 Mbps ATM, to provide two ATM- Ring connections for servers or backbone connectivity.

Stack Link Module—the switch supports a stack link module that can be used to connect two switches from the CrossFire 8600 series in a back-to-back configuration. Alternatively, up to five switches can be connected together using and internal stacker module, and up to eight switches can be connected together using the stack link module and an additional switch stack unit. By connecting switches together through the stack link module, the switches virtually combine to form a single unit, providing scalability, simplified management, and enhanced performance.

CrossFire 8600/8605 Token-Ring Switches v. 1.2, P/N: 710001641 Switch Theory of Operation