i3 International S81, User Manual

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Spanning Tree CIST Port Configuration Parameters:
Items Description
Port The switch port number of the logical STP port.
STP Enabled Controls whether STP is enabled on this switch port.
Path Cost Controls the path cost incurred by the port. The Auto setting will set the path cost as appropriate
by the physical link speed, using the 802.1D recommended values. Using the Specific setting, a
user-defined value can be entered. The path cost is used when establishing the active topology
of the network. Lower path cost ports are chosen as forwarding ports in favor of higher path
cost ports. Valid values are in the range 1 to 200000000.
Priority Controls the port priority. This can be used to control priority of ports having identical path cost
AdminEdge Controls whether the operEdge flag should start as set or cleared. (The initial operEdge
state when a port is initialized).
AutoEdge Controls whether the bridge should enable automatic edge detection on the bridge port. This
allows operEdge to be derived from whether BPDU's are received on the port or not.
Restricted Role If enabled, causes the port not to be selected as Root Port for the CIST or any MSTI, even if
it has the best spanning tree priority vector. Such a port will be selected as an Alternate
Port after the Root Port has been selected. If set, it can cause lack of spanning tree connectivity.
It can be set by a network administrator to prevent bridges external to a core region of the
network influence the spanning tree active topology, possibly because those bridges are not
under the full control of the administrator. This feature is also known as Root Guard.
Restricted TCN If enabled, causes the port not to propagate received topology change notifications and
topology changes to other ports. If set it can cause temporary loss of connectivity after
changes in a spanning tree's active topology as a result of persistently incorrect learned
station location information. It is set by a network administrator to prevent bridges external to
a core region of the network, causing address flushing in that region, possibly because those
bridges are not under the full control of the administrator or the physical link state of the attached
LANs transits frequently.
BPDU Guard If enabled, causes the port to disable itself upon receiving valid BPDU's. Contrary to the similar
bridge setting, the port Edge status does not affect this setting. A port entering error-disabled
state due to this setting is subject to the bridge Port Error Recovery setting as well.
Point to Point Controls whether the port connects to a point-to-point LAN rather than to a shared
medium. This can be automatically determined, or forced either true or false. Transition to
the forwarding state is faster for point-to-point LANs than for shared media.