Spanning-Tree Operation

802.1D Spanning-Tree Protocol (STP)

Lists STP configuration.

Shows the default

STP protocol

1. Changes the Spanning-Tree protocol to STP (required for Fast-Uplink).

2. Saves the change to the startup-configuration

3. Reboots the switch. (Required for this configuration

Figure 5-24. Example of Changing the STP Configuration from the Default RSTP (802.1w) to STP (802.1D)

Syntax: spanning-tree < port/trunk-list> mode uplink

Enables STP on the switch and configures fast-uplink STP on the designated interfaces (port or trunk).

For example:

ProCurve(config)# spanning-tree e A1,trk1 mode uplink

Operating Notes

Effect of Reboots on Fast-Uplink STP Operation. When configured, fast-uplink STP operates on the designated ports in a running switch. How­ ever, if the switch experiences a reboot, the fast-uplink ports (Mode = Uplink) use the longer forwarding delay used by ports on standard 802.1D STP (non fast-uplink). This prevents temporary loops that could otherwise result while the switch is determining the STP status for all ports. That is, on ports configured for fast-uplink STP, the first STP state transition after a reboot takes the same amount of time as for redundant ports that are not configured for fast-uplink STP.

Using Fast Uplink with Port Trunks. To use a port trunk for fast-uplink STP, configure it in the same way that you would an individual port for the same purpose. A port trunk configured for fast uplink operates in the same way as an individual, non-trunked port operates; that is, as a logical port.

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