Chapter 1 1 Configuring Stp Extensions; About Stp Extensions; Information About Stp Extensions; Understanding Stp Port Types - Cisco Nexus 5000 Series Configuration Manual

Configuring STP Extensions
This chapter describes the configuration of extensions to the Spanning Tree Protocol (STP) on Cisco Nexus
5000 Series switches. It includes the following sections:
•

About STP Extensions

Cisco has added extensions to STP that make convergence more efficient. In some cases, even though similar
functionality may be incorporated into the IEEE 802.1w Rapid Spanning Tree Protocol (RSTP) standard, we
recommend using these extensions. All of these extensions can be used with both RPVST+ and MST.
The available extensions are spanning tree port types, Bridge Assurance, BPDU Guard, BPDU Filtering, Loop
Guard, and Root Guard. Many of these features can be applied either globally or on specified interfaces.
Spanning tree is used to refer to IEEE 802.1w and IEEE 802.1s. If the text is discussing the IEEE 802.1D
Note
Spanning Tree Protocol, 802.1D is stated specifically.

Information About STP Extensions

Understanding STP Port Types

You can configure a spanning tree port as an edge port, a network port, or a normal port. A port can be in
only one of these states at a given time. The default spanning tree port type is normal. Depending on the type
of device to which the interface is connected, you can configure a spanning tree port as one of these port types.

Spanning Tree Edge Ports

Edge ports, which are connected to hosts, can be either an access port or a trunk port. The edge port interface
immediately transitions to the forwarding state, without moving through the blocking or learning states. (This
immediate transition was previously configured as the Cisco-proprietary feature PortFast.)
About STP Extensions, page 201
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