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An edge port is a port with spanning-tree port-fast enabled. A point-to-point
link is a link configured as full-duplex. Edge-ports and point-to-point links
directly transition to the forwarding state and do not delay for the listening
and learning stages of spanning-tree. An edge port that receives a BPDU is no
longer considered an edge-port and will utilize the configured port priority
value.
All interfaces and VLANs have 128 as priority value by default. By default,
spanning-tree puts the lowest numbered operationally enabled interface in
the forwarding state and blocks other interfaces. The priority value is used to
override this default behavior. Interfaces with lower port priorities are
preferred for forwarding over interfaces with numerically higher priority
values. STP-PV/RSTP-PV uses the port priority value when the LAN port is
configured as an edge port and uses the VLAN priority value when the
interface is configured as a point-to-point link. MSTP uses the port priority
regardless of whether the port is an edge port or not.
Example
The following example configures a port connected to a host to be least likely
to be selected for forwarding to the root bridge, even if the host begins to
send BPDUs.
console(config-if-Gi1/0/1)#spanning-tree port-priority 240
console(config-if-Gi1/0/1)#spanning-tree vlan 10 port-priority 240
spanning-tree priority
Use the spanning-tree priority command in Global Configuration mode to
configure the spanning-tree priority. The priority value is used to determine
which bridge is elected as the root bridge. To reset the default spanning-tree
priority use the no form of this command.
Syntax
spanning-tree priority priority
no spanning-tree priority
•
priority — Priority of the bridge. (Range: 0–61440)
Default Configuration
The default bridge priority for IEEE STP is 32768.
764
Layer 2 Switching Commands
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