Cist General - Siemens SIMATIC NET SCALANCE W780 Series Configuration Manual

Configuring with Web Based Management
6.7 "Layer 2" menu
6.7.3.2

CIST General

MSTP-CIST configuration
The page consists of the following parts.
● The left-hand side of the page shows the configuration of the device.
● The central part shows the configuration of the root bridge that can be derived from the
spanning tree frames received by an device.
● The right-hand side shows the configuration of the regional root bridge that can be
derived from the MSTP frames received by an device. The displayed data is only visible if
you have enabled "Spanning Tree" on the "General" page and when "Protocol
Compatibility" is set to "MSTP". This also applies to the "Bridge Max Hop Count"
parameter. If the device is a root bridge, the information on the left and right matches.
Description
The page contains the following boxes:
● Bridge Priority / Root Priority
Which device becomes the root bridge is decided based on the bridge priority . The
bridge with the highest priority becomes the root bridge. The lower the value, the higher
the priority. If several devices in a network have the same priority, the device whose MAC
address has the lowest numeric value will become the root bridge. Both parameters,
bridge priority and MAC address together form the bridge identifier. Since the root bridge
manages all path changes, it should be located as centrally as possible due to the delay
of the frames. The value for the bridge priority is a whole multiple of 4096 with a range of
values from 0 to 61440.
● Bridge Address / Root Address
The bridge address shows the MAC address of the device and the root address shows
the MAC address of the root bridge.
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SCALANCE W780/W740 to IEEE 802.11n Web Based Management
Configuration Manual, 08/2018, C79000-G8976-C267-13