Alcatel-Lucent OmniSwitch 6250, Cli Reference Manual, Page: 441 / 2018

OmniSwitch 6250 CLI Reference Guide November 2009 page 16-1
16 Distributed Spanning
Tree Commands
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 and port
link up and down states in the event of a fail over to a backup management module or switch.
In addition to a distributed architecture, this implementation also provides the following Spanning Tree
features:
•
Automatic configuration of a physical topology into a single Spanning Tree to ensure that there is only
one data path between any two switches.
•
Fault tolerance within the network topology. The Spanning Tree is reconfigured in the event of a data
path or bridge failure or when a new switch is added to the topology.
•
Support for four Spanning Tree protocols: 802.1D (STP), 802.1W (RSTP), 802.1Q 2005 (MSTP), and
RRSTP.
•
A flat Spanning Tree operating mode. If STP or RSTP is used, this mode applies a single STP instance
across all VLANs. If MSTP is used, this mode applies a single STP instance to each Multiple Span-
ning Tree Instance (MSTI), which identifies a set of VLANs.
•
Support for up to 16 MSTIs per switch. In addition, there is always one Common and Internal Span-
ning Tree (CIST) instance 0 on each switch.
•
Ring Rapid Spanning Tree Protocol (RRSTP) supports up to 128 rings per switch. Note that there can
be no alternate connections for the same instance between any two switches within an RRSTP ring
topology.
•
A 1x1 Spanning Tree operating mode, which applies a single STP instance for each defined VLAN on
the switch.
•
An STP topology that includes 802.1Q tagged ports and link aggregate logical ports in the calculation
of the physical topology.
MIB information for Distributed Spanning Tree commands is as follows:
Filename : AlcatelIND1VlanSTP.MIB
Module : STP-MGMT-MIB