11 CONFIGURING SPANNING TREE
This section contains information for configuring the Spanning Tree
Algorithm (STA). This algorithm provides a tree topography for any
arrangement of bridges. It also provides a single path between end
stations on a network, eliminating loops.
Loops occur when alternate routes exist between hosts. Loops in an
extended network can cause bridges to forward traffic indefinitely,
resulting in increased traffic and reduced ne twork efficiency.
The device supports the following STA versions:
■Spanning Tree Protocol (STP, IEEE 802.1D) — This protocol provides
loop detection. When there are multiple physical paths between
segments, this protocol will choose a single path and disable all others
to ensure that only one route exists between any two stations on the
network. This prevents the creation of network loops. However, if the
chosen path should fail for any reason, an alternate path will be
activated to maintain the connection.
■Rapid Spanning Tree Protocol (RSTP, IEEE 802.1w) — This protocol
reduces the convergence time for network topology changes to about
3 to 5 seconds, compared to 30 seconds or more for the IEEE 802.1D
STP standard. It is intended as a complete replacement for STP, but can
still interoperate with switches running the STP protocol, by
automatically reconfiguring ports to STP-compliant mode if they
detect STP protocol messages from attached devices.
This section contains the following topics:
■Viewing Spanning Tree
■Defining Global Settings for Spanning Tree
■Defining Port Settings for Spanning Tree