Configuring Spanning Tree Parameters - Alcatel-Lucent OmniSwitch 6800 Series Network Configuration Manual

7 Configuring Spanning Tree
The Spanning Tree Algorithm and Protocol (STP) is a self-configuring algorithm that maintains a loop-
free topology while providing data path redundancy and network scalability. Based on the IEEE 802.1D
standard, the Alcatel-Lucent STP implementation distributes the Spanning Tree load between the primary
management module and the network interface modules. In the case of a stack of switches, the STP load is
distributed between the primary management switch and other switches in the stack. This functionality
improves network robustness by providing a Spanning Tree that continues to respond to BPDUs (Bridge
Protocol Data Unit) and port link up and down states in the event of a fail over to a backup management
module or switch.
The Alcatel-Lucent distributed implementation also incorporates the following Spanning Tree features:
•
Configures a physical topology into a single Spanning Tree to ensure that there is only one data path
between any two switches.
•
Supports fault tolerance within the network topology. The Spanning Tree is configured again in the
event of a data path or bridge failure or when a new switch is added to the topology.
•
Supports two Spanning Tree operating modes; flat (single STP instance per switch) and 1x1 (single
STP instance per VLAN). 1x1 mode can be configured to interoperate with Cisco's properiatary Per
VLAN Spanning Tree instance (PVST+).
•
Supports four Spanning Tree Algorithms; 802.1D (STP), 802.1w (RSTP), 802.1Q 2005 (MSTP), and
RRSTP.
•
Allows 802.1Q tagged ports and link aggregate logical ports to participate in the calculation of the STP
topology.
The Distributed Spanning Tree software is active on all switches by default. As a result, a loop-free
network topology is automatically calculated based on default Spanning Tree switch, VLAN, and port
parameter values. It is only necessary to configure Spanning Tree parameters to change how the topology
is calculated and maintained.
OmniSwitch 6800/6850/9000 Network Configuration Guide
Parameters
March 2008 page 7-1