Ericsson ECN330, User Manual

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Configuring the ECN330-switch
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1553-KDU 137 365 Uen D 2006-06-16
MSTP connects all bridges and LAN segments with a single Common and
Internal Spanning Tree (CIST). The CIST is formed as a result of the running
spanning tree algorithm between switches that support the STP, RSTP, MSTP
protocols.
6.10.1 Displaying Global Settings
Using the STA Information screen, a summary of the current bridge STA
information that applies to the entire ECN330-switch can be displayed.
Field Attributes
• Spanning Tree State – Shows if the ECN330-switch is enabled to
participate in an STA-compliant network.
• Bridge ID – A unique identifier for this bridge, consisting of the bridge
priority, the MST Instance ID 0 for the Common Spanning Tree when
spanning tree mode is set to MSTP (see “Configuring Global Settings”
on page 238), and the MAC address (where the address is taken from
the ECN330-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.
• Forward Delay – The maximum time (in seconds) the root device will
wait before changing states (that is, discarding to learning to
forwarding). This delay is required because every device must receive
information about topology changes before it starts to forward frames.
In addition, each port needs time to listen for conflicting information that
would make it return to a discarding state; otherwise, temporary data
loops might result.
• Designated Root – The priority and MAC address of the device in the
Spanning Tree that the ECN330-switch has accepted as the root device.