Chapter 20: Spanning Tree Protocol; Overview Of The Spanning Tree Protocol; Spanning Tree Domains - Extreme Networks ExtremeWare XOS Guide Manual

20 Spanning Tree Protocol
This chapter covers the following topics:
Overview of the Spanning Tree Protocol on page 423
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Spanning Tree Domains on page 423
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STP Configurations on page 430
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Per VLAN Spanning Tree on page 436
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Rapid Spanning Tree Protocol on page 436
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STP Rules and Restrictions on page 447
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Configuring STP on the Switch on page 447
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Displaying STP Settings on page 452
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Using the Spanning Tree Protocol (STP) functionality of the switch makes your network more fault
tolerant. The following sections explain more about STP and the STP features supported by
ExtremeWare XOS.
NOTE
STP is a part of the 802.1D bridge specification defined by the IEEE Computer Society. To explain STP in terms
used by the IEEE 802.1D specification, the switch will be referred to as a bridge.

Overview of the Spanning Tree Protocol

STP is a bridge-based mechanism for providing fault tolerance on networks. STP allows you to
implement parallel paths for network traffic and to ensure that redundant paths are:
Disabled when the main paths are operational.
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Enabled if the main path fails.
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NOTE
STP and Extreme Standby Router Protocol (ESRP) cannot be configured on the same Virtual LAN (VLAN)
simultaneously.

Spanning Tree Domains

The switch can be partitioned into multiple virtual bridges. Each virtual bridge can run an independent
Spanning Tree instance. Each Spanning Tree instance is called a Spanning Tree Domain (STPD). Each
STPD has its own root bridge and active path. After an STPD is created, one or more VLANs can be
assigned to it.
A physical port can belong to multiple STPDs. In addition, a VLAN can span multiple STPDs.
ExtremeWare XOS 11.3 Concepts Guide
423