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718 Appendix A: Answers to the "Do I Know This Already?" Quizzes and Q&A Sections
16
Name the three VTP modes. Which of these does not allow VLANs to be added or
modified?
Server and client modes are used to actively participate in VTP, and transparent mode is
used to simply stay out of the way of servers and clients while not participating in VTP.
Switches in client mode cannot change or add VLANs.
Answers to the Chapter 4 Q&A Section
1
What do the letters MAC stand for? What other terms have you heard to describe the same
or similar concept?
Media Access Control (MAC). Many terms are used to describe a MAC address: NIC,
LAN, hardware, burned-in, UAA (Universally Administered Address), LAA (Locally
Administered Address), Ethernet, Token Ring, FDDI, card, wire, and real are all terms
used to describe this same address in different instances.
2
Name two benefits of LAN segmentation using transparent bridges.
The main benefits are reduced collisions and more bandwidth. Multiple 10- or 100-Mbps
Ethernet segments are created, and unicasts between devices on the same segment are not
forwarded by the bridge, which reduces overhead.
3
What routing protocol does a transparent bridge use to learn about Layer 3 addressing
groupings?
None. Bridges do not use routing protocols. Transparent bridges do not care about Layer
3 address groupings. Devices on either side of a transparent bridge are in the same Layer
3 group--in other words, the same IP subnet or IPX network.
4
What settings are examined by a bridge or switch to determine which should be elected as
root of the Spanning Tree?
The bridge priority is first examined (the lowest wins). In case of a tie, the lowest bridge
ID wins. The priority is prepended to the bridge ID in the actual CBPDU message so that
the combined fields can be easily compared.
5
Define the term VLAN.
Virtual LAN (VLAN) refers to the process of treating one subset of a switch's interfaces
as one broadcast domain. Broadcasts from one VLAN are not forwarded to other VLANs;
unicasts between VLANs must use a router. Advanced methods, such as Layer 3 switching
in a NetFlow feature card in a Catalyst 5000 switch, can be used to allow the LAN switch
to forward traffic between VLANs without each individual frame being routed by a router.
However, for the depth of CCNA, such detail is not needed.
apA.fm Page 718 Monday, March 20, 2000 5:24 PM