Dell PowerConnect 3524 User's Guide - Page 13

Understanding the Stack Topology The PowerConnect 35xx series systems operates in a Ring topology. A stacked Ring topology is where all devices in the stack are connected to each other forming a circle. Each device in the stack accepts data and sends it to the device to which it is attached. The packet continues through the stack until it reaches its destination. The system discovers the optimal path on which to send traffic. Figure 1-3. Stacking Ring Topology Ring Topology Most difficulties incurred in Ring topologies occur when a device in the ring becomes non-functional, or a link is severed. With the PowerConnect 3524/P and PowerConnect 3548/P stack, the system automatically switches to a Stacking Failover topology without any system downtime. An SNMP message is automatically generated, but no stack management action is required. However, the stacking link or stacking member must be repaired to ensure the stacking integrity. After the stacking issues are resolved, the device can be reconnected to the stack without interruption, and the Ring topology is restored. Stacking Failover Topology If a failure occurs in the stacking topology, the stack reverts to Stacking Failover Topology. In the Stacking Failover topology, devices operate in a chain formation. The Stack Master determines where the packets are sent. Each unit is connected to two neighboring devices, except for the top and bottom units. Stacking Members and Unit ID Stacking Unit IDs are essential to the stacking configuration. The stacking operation is determined during the boot process. The operation mode is determined by the Unit ID selected during the initialization process. For example, if the user selected the stand-alone mode, the device boots in the boot-up process as a stand-alone device. Introduction 13