1-11 XRN Fabric ConfigurationWhen configuring XRN fabric, go to these sections for information you are interested in:z Introduction to XRNz XRN Fabric Configurationz Displaying and Maintaining XRN Fabricz XRN Fabric Configuration ExampleIntroduction to XRNExpandable Resilient Networking (XRN), a feature particular to 3Com Switch 4500 series switches, is anew technology for building the core of a network. This feature allows you to build an XRN fabric byinterconnecting several Switch 4500 series switches to provide more ports for network devices andimprove the reliability of your network.Establishment of an XRN FabricTopology and connections of an XRN fabricAn XRN fabric typically has a bus topology structure. As shown in Figure 1-1, each switch has two portsconnected with two other switches in the fabric, but the switches at both ends of the bus have only oneport connected. These ports are called fabric ports in general, a left port and a right port respectively;the other ports, which are available for connections with users or devices outside the fabric, are calleduser ports.Figure 1-1 A schematic diagram of an XRN fabricA correctly built XRN fabric features the following:z Multiple Switch 4500 series switches are interconnected through their fabric ports.z Given a switch, its left port is connected to the right port of another switch, and its right port isconnected to the left port of a third one.Port connection mode for Switch 4500 series bus topology XRN fabric is shown in Figure 1-2.
