Answers to Review Questions
223
Answers to Review Questions
1.
C. The Spanning Tree Protocol was designed to help stop networks
loops that can happen with transparent bridge networks running
redundant links.
2.
A, B, C, E. The Bridge Protocol Data Units are sent out every 2 sec-
onds by default and provide information to switches throughout the
internetwork. This includes finding redundant links, electing the root
bridge, monitoring the links in the spanning tree, and notifying other
switches in the network about link failures.
3.
C. VLAN 1 is a default VLAN and used for management by default.
4.
D. The Cisco proprietary protocol Per-VLAN Spanning Tree (PVST)
uses a separate instance of spanning tree for each and every VLAN.
5.
C. The
set spantree root secondary
command allows you to
configure a backup root bridge.
6.
D. The 1900 switch can support up to 1,005 VLANs but only up to
64 STP instances.
7.
A. On an IOS-based switch, a 1900 for example, use the spantree
priority 16
from interface configuration to change the port priority.
8.
A. A priority from 0 to 63 can be set for each VLAN.
9.
C. Should one link in the bundle fail, the Ethernet Bundle Controller
(EBC) informs the Enhanced Address Recognition Logic (EARL)
ASIC of the failure, and the EARL in turn ages out all addresses
learned on that link.
10.
A. PAgP bundled ports must all be configured the same, including the
duplex and speed. Also, dynamic VLANs will not work, so VLANs
must be assigned statically or they all must be trunked ports.
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