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Chapter 5
Using Spanning Tree with VLANs
11.
A. The switch will use the port ID to find the best forwarding port if
the link costs are equal.
12.
B. PortFast is used to put a blocked port into forwarding state imme-
diately upon a boot up of a point-to-point device such as a work-
station or server.
13.
D. When BackboneFast is turned on, the Root Link Query BPDUs
are sent out as soon as an inferior BPDU is received. This basically can
enable faster convergence in the event of a backbone link failure.
14.
B. The command
set port channel [slot/port] [on/off]
is
used to create an EtherChannel bundle.
15.
C. To enable BackboneFast on a switch, use the set spantree
backbonefast enable
command, which turns the protocol on for
every VLAN.
16.
A, B, D. PVST is proprietary to Cisco and PVST+ is an extension of
PVST. PVST+ allows non-PVST information to be accepted and
received into PVST, adds configuration checking, and allows Cisco
switches to support 802.1q.
17.
A. The IEEE uses what is called Common Spanning Tree (CST),
which is defined with IEEE 802.1q. The IEEE 802.1q defines one
spanning tree instance for all VLANs.
18.
C. The PVST protocol defines one instance of STP per VLAN.
19.
B. The CST protocol defines one instance of STP per network regard-
less of the amount of VLANs configured.
20.
B, C, E. The port cost, path cost, and port priority are used to deter-
mine the best path to the root bridge.
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