SMC Networks 6128L2, Management Manual

Page: 200 / 606

C
ONFIGURING THE
S
WITCH
3-146
RSTP is designed as a general replacement for the slower, legacy STP.
RSTP achieves must faster reconfiguration (i.e., around one tenth of the
time required by STP) by reducing the number of state changes before
active ports start learning, predefining an alternate route that can be used
when a node or port fails, and retaining the forwarding database for ports
insensitive to changes in the tree structure when reconfiguration occurs.
When using STP or RSTP, it may be difficult to maintain a stable path
between all VLAN members. Frequent changes in the tree structure can
easily isolate some of the group members.
Displaying Global Settings
You can display a summary of the current bridge STA information that
applies to the entire switch using the STA Information screen.
Field Attributes
• Spanning Tree State – Shows if the switch is enabled to participate
in an STA-compliant network.
• Bridge ID – A unique identifier for this bridge, consisting of the
bridge priority and MAC address (where the address is taken from the
switch system).
• Max Age – The maximum time (in seconds) a device can wait without
receiving a configuration message before attempting to reconfigure.
All device ports (except for designated ports) should receive
configuration messages at regular intervals. Any port that ages out STA
information (provided in the last configuration message) becomes the
designated port for the attached LAN. If it is a root port, a new root
port is selected from among the device ports attached to the network.
(References to “ports” in this section mean “interfaces,” which
includes both ports and trunks.)
• Hello Time – Interval (in seconds) at which the root device transmits
a configuration message.