When STP UplinkFast is enabled on a switch utilizing the default bridge priority, what will the new
bridge priority be changed to?
A.
8192
B.
16384
C.
49152
D.
65535
Explanation:
The STP UplinkFast is used to fast switchover to alternate ports when the root port fails. When
STP UplinkFast is enabled on a switch utilizing the default bridge priority (32768), the new bridge
priority will be changed to 49152. The reason for the priority being raised is to prevent the switch
from becoming the root (recall that lower bridge priority is preferred). To enable UplinkFast feature,
use the “set spantree uplinkfast enable” in privileged mode
The set spantree uplinkfast enable command has the following results:
Changes the bridge priority to 49152 for all VLANs (allowed VLANs).
Increases the path cost and portvlancost of all ports to a value greater than 3000.
On detecting the failure of a root port, an instant cutover occurs to an alternate port selected by
Spanning Tree Protocol (without using this feature, the network will need about 30 seconds to reestablish the connection.http://www.cisco.com/en/US/tech/tk389/tk621/technologies_tech_note09186a0080094641.shtml