Cisco 640-802: Practice Exam
m
A. Port Fa0/2 on Switch1 B. Port Fa0/1 on Switch2 C. Port Fa0/1 on Switch1 D. Port Fa0/2 on Switch2
.co
Answer: C
Ac
tua
lTe
sts
Explanation: First find out which switch port will become blocking mode through root-bridge election. Root-bridge election: Bridge ID = Bridge Priority + Bridge MAC address The default bridge priority is 32,768. In this case, you only need to compare two switch MAC addresses. The MAC address of Switch2 is the smallest one. Therefore it will be the root-bridge of this switching network. As a non-root bridge, an interface of Switch1 will be blocked by STP. Compare the speed of the links that Fa0/1 and Fa0/2 connect, you'll find that the link that Fa0/1 connects needs much higher cost. Therefore Fa0/1 will be blocked. Spanning-Tree Protocol (STP) is a Layer 2 protocol that utilizes a special-purpose algorithm to discover physical loops in a network and effect a logical loop-free topology. STP creates a loopfree tree structure consisting of leaves and branches that span the entire Layer 2 network. The actual mechanics of how bridges communicate and how the STP algorithm works will be discussed at length in the following topics. Note that the terms bridge and switch are used interchangeably when discussing STP. In addition, unless otherwise indicated, connections between switches are assumed to be trunks.
"Pass Any Exam. Any Time." - www.actualtests.com
106