Chapter 9: Layer 2 Loop Prevention; Spanning Tree; Spanning Tree Protocol - Avaya 8800 Planning And Engineering, Network Design

Chapter 9: Layer 2 loop prevention

To use bandwidth and network resources efficiently, prevent layer 2 data loops. Use the information
in this section to help you use loop prevention mechanisms.

Spanning tree

Spanning Tree prevents loops in switched networks. The Avaya Ethernet Routing Switch 8800/8600
supports several spanning tree protocols and implementations. These include the Spanning Tree
Protocol (STP), Per-VLAN Spanning Tree Plus (PVST+), Rapid Spanning Tree Protocol (RSTP),
and Multiple Spanning Tree Protocol (MSTP). This section describes some issues to consider when
you configure spanning tree.
For more information about spanning tree protocols, see Avaya Ethernet Routing Switch 8800/8600
Configuration — VLANs and Spanning Tree, NN46205-517.
Spanning tree navigation
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Spanning Tree Protocol

• Per-VLAN Spanning Tree Plus
• MSTP and RSTP considerations
Spanning Tree Protocol
Use Spanning Tree Protocol (STP) to prevent loops in your network. This section provides some
STP guidelines.
STP and BPDU forwarding
You can enable or disable STP at the port or at the spanning tree group (STG) level. If you disable
the protocol at the STG level, Bridge Protocol Data Units (BPDU) received on one port in the STG
are flooded to all ports of this STG regardless of whether the STG is disabled or enabled on a per
port basis. When you disable STP at the port level and STG is enabled globally, the BPDUs
received on this port are discarded by the CPU.
June 2016
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Planning and Engineering — Network Design
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