Enhancements in Release F.02.11

 

Fast-Uplink Spanning Tree Protocol (STP)

Syntax:

spanning-tree e <port/trunk-list> mode uplink Enables STP on the switch and configures

fast-uplink STP on the designated interfaces (port or trunk).

HP2512(config)# spanning-tree e 1,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 Series 2500 switch. However, 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.

Note

When you add a port to a trunk, the port takes on the STP mode configured for the trunk, regardless of which STP mode was configured on the port before it was added to the trunk. Thus, all ports belonging to a trunk configured with Uplink in the STP Mode field will operate in the fast-uplink mode. (If you remove a port from a trunk, the port reverts to the STP Mode setting it had before you added the port to the trunk.

To use fast uplink over a trunk, you must:

1.Create the trunk.

2.Configure the trunk for fast uplink in the same way that you would configure an individual port for fast uplink.

When you first create a port trunk, its STP Mode setting will be Norm, regardless of whether one or more ports in the trunk are set to fast uplink (Mode = Uplink). You must still specifically configure the trunk Mode setting to Uplink. Similarly, if you eliminate a trunk, the Mode setting on the individual ports in the trunk will return to their previous settings.

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