Enhancements in Release F.02.11

Fast-Uplink Spanning Tree Protocol (STP)

Fast-Uplink Troubleshooting

Some of the problems that can result from incorrect usage of Fast-Uplink STP include temporary loops and generation of duplicate packets.

Problem sources can include:

Fast-Uplink is configured on a switch that is the STP root device.

Either the Hello Time or the Max Age setting (or both) is too long on one or more switches. Return the Hello Time and Max Age settings to their default values (2 seconds and 20 seconds, respectively, on a Series 2500 switch).

A "downlink" port is connected to a switch that is further away (in hop count) from the root device than the switch port on which fast-uplink STP is configured.

Two edge switches are directly linked to each other with a fast-uplink (Mode = Uplink) connection.

Fast uplink is configured on both ends of a link.

A switch serving as a backup STP root switch has ports configured for fast-uplink STP and has become the root device due to a failure in the original root device.

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