Chapter 8
Backbone Networks
True-False Questions
The following are possible True/False questions for tests. The statement is given and the answer
is provided. The level of difficulty (easy, medium, hard) and the section(s) relevant to the topic
are also furnished.
1.
A backbone network is a high-speed network that connects many networks
2.
Backbone networks typically use lower speed circuits to interconnect a series of LANs and
provide connections to other backbone networks.
3.
A backbone network that connects many backbone networks spanning several buildings at a
single location is often called an Internet backbone.
4.
One basic component of a backbone network is the hardware device that connects other
networks to the backbone.
5.
Switches and routers are devices that can connect networks to the BN.
6.
The cable to connect BNs is usually twisted pair.
7.
A hardware device that operates at the application layer is a router.
8.
Routers can only connect the same type of cable.
9.
Routers use network layer address to forward packets between network segments.
10.
Routers operate at the application layer.
11.
Routers connect two or more network segments that use the same or different data link
protocols, but the same network protocol.
12.
One difference between a switch and a router is that a router will only process messages
addressed to the router, while a switch processes all messages.
13.
Layer-3 switches switch messages based on their data link layer address.
14.
Routed backbones use switches that move packets based on data link layer addresses.
15.
The distribution layer of a backbone connects LANs together.
L.O.: Understand the switched backbone architecture
16.
The primary advantage of a routed backbone is that it clearly segments each part of the
network connected to the backbone because each segment has its own subnet addresses that
can be managed separately.
17.
One advantage of a routed backbone is that is requires little management.
L.O.: Understand the routed backbone architecture
18.
A routed backbone tends to be used more for large networks than VLANs, although VLAN
high speed switches and this new type of LAN-BN architecture are now being considered.
Answer: True
19.
A switched backbone uses a bus topology
20.
A room that contains a rack of equipment for a rack-based collapsed backbone is also called
the main distribution facility (MDF) or central distribution facility (CDF).
21.
A key advantage of a chassis switch is its flexibility.
22.
A VLAN network assigns computers to LAN segments by hardware.
23.
A VLAN requires the computer manager to reconfigure the physical cables to the switch if a
computer is moved from one port to another port on a switch.
24.
VLANs provide faster performance compared to switched, collapsed or routed backbone
architectures.
MULTIPLE CHOICE
The following are possible multiple-choice questions for tests. The question is posed and the
answer is provided under the choices. The level of difficulty (easy, medium, hard) and the page
number(s) relevant to the topic is also furnished.
1.
Which of the following is not true about backbone networks?
a. They may also be called enterprise networks if they connect all networks within an
organization.
b. They typically connect many networks, including LANs.
c. They typically provide connections to other BNs, WANs, MANs, and the Internet.
d. They may also be called campus networks if they connect many BNs spanning
several buildings as a single location.
e. They tend to use lower speed circuits than LANs.
2.
Which of the following is not a type of hardware device that can be used to interconnect
networks?
a. layer 3 switches
b. routers
c. dumb terminals
d. layer 2 switches
e. all of the above can be used
3.
Switches:
a. learn addresses by reading the source and destination addresses
b. operate at the physical layer only
c. connect two ore more network segments that use different data link protocols
d. connect two or more network segments that use different network protocols
e. have become more popular than layer 2 switches
4.
Routers:
a. operate at the application layer
b. operate only at the physical layer
c. cannot connect two or more networks that use the same type of cable
d. may also be called TCP/IP gateways
e. operate only at the data link layer
5.
Which of the following is not a way that a router differs from a switch?
a. routers can connect two or more networks that use the same data link protocol
b. routers only process messages that are specifically addressed to it
c. routers operate at the network layer
d. routers perform more processing on each message than switch
e. routers can choose the “best” route between networks for forwarding a packet
6.
Which of the following is not true about Layer-3 switches?
a. They switch messages based on their IP address.
b. They can be used in place of routers.
c. They function faster than routers.
d. They have more simultaneously active ports than routers.
e. They can only switch messages based on their data link layer addresses.
7.
Which of the following is a fundamental backbone network architecture?
a. Bridged backbone
b. Virtual LAN
c. Hubbed backbone
d. Gatewayed backbone
e. Virtual backbone
8.
Which of the following is not a technology layer that is considered when designing backbone
networks?
a. access layer
b. distribution layer
c. decentralized layer
d. core layer
e. none of the options
9.
A subnetted or hierarchical backbone can also be called:
a. Bridged backbone
b. Virtual LAN
c. Hubbed backbone
d. Collapsed backbone
e. Routed backbone
10.
_________ move packets along the backbone based on their network layer address.
a. Bridged backbones
b. Hubbed backbones
c. Multistation access unit backbones
d. Routed backbones
e. NIC backbones
11.
Routers:
a. require more management than switches
b. are not susceptible to time delays
c. use data link layer addresses to move packets that leave the subnet
d. require only a few set of TCP/IP addresses
e. don’t need much time to establish separate subnet addresses for each LAN
12.
A _____________ type of BN segments (each of which has a special set of subnet addresses
that can be managed by different network managers) each part of the network connected to
the backbone.
a. bridged backbone
b. virtual LAN
c. hubbed backbone
d. collapsed backbone
e. routed backbone
13.
A __________ type of BN has a star topology with one device, such as a switch, at its center.
a. Bridged backbone
b. Virtual LAN
c. Hubbed backbone
d. Switched backbone
e. Routed backbone
14.
_________ have no backbone cable.
a. Switched backbones
b. Cloud routed backbones
c. Hubbed backbones
d. Bridged backbones
e. Multistation access unit backbones
15.
Switched backbone networks:
a. always use a ring topology
b. are the least common type of BN used in one building
c. use a star topology with one device, usually a switch
d. have a great deal of cable in their backbones
e. tend to have less cable, but more network devices
16.
Which of the following is not true about switched backbones?
a. performance is improved over traditional (bridged or routed) backbone networks
b. each connection into the switch is a separate point–to-point circuit which supports
simultaneous access by the LANs connected to the switch
c. there are many more networking devices in a switched backbone network
d. if the switch fails, so does the entire backbone network
e. the backbone essentially exists in the switch; there is no backbone cable
17.
Which of the following is true regarding switched backbones?
a. They place all network devices for one part of the building physically in the same
room, often in a rack of equipment
b. They have an advantage of requiring less cable
c. They make it more difficult to move computers from one LAN to another
d. Network capacity is always tied to the physical location of the computers
e. They are harder to maintain and upgrade than a BN that is not rack-based
18.
Associated with a switched backbone, MDF is an acronym for:
a. multi-station device foundation
b. main distribution facility
c. manual data frequency
d. multiplexer downstream flow
e. maximum data facility
19.
A _____________ type of BN is a new type of LAN/BN architecture made possible by
intelligent, high speed switches that assign computers to LAN segments via software, rather
than by hardware.
a. Bridged backbone
b. Virtual LAN
c. Hubbed backbone
d. Collapsed backbone
e. Routed backbone
20.
Which of the following is not true about multiswitch VLANs?
a. Several switches are used to build a VLAN
b. The switches in the VLAN can send packets among themselves in a way that
identifies the VLAN to which the packet belongs.
c. In some multi-switch VLANs, the Ethernet packet is modified based on the emerging
IEEE 802.1q standard.
d. In some multi-switch VLANs, a new VLAN packet encapsulates the Ethernet packet.
e. All of the above are true statements.
21.
Which of the following would be least effective in improving backbone performance?
a. improving the computers in the network
b. changing the demand placed on the network
c. adding new keyboards to the client computers
d. upgrading the circuits between computers
e. improving devices in the network
22.
Circuit capacity on a backbone network will not be improved by:
a. going from 100Base-T Ethernet to 10Base-T Ethernet
b. going from 100Base-T Ethernet to gigabit Ethernet
c. adding additional circuits alongside heavily used ones
d. replacing a shared circuit backbone with a switched circuit backbone
e. providing a faster circuit to the server
23.
Device performance on a backbone network will not be improved by:
a. using the same protocols in the backbone and the LANs
b. using static routing in low to moderate traffic conditions
c. ensuring that backbone devices have sufficient memory so that packets do not have
to be retransmitted by the sender
d. translating packets from one protocol to another as they enter the BN
e. none of the options
24.
Network demand will not be reduced by:
a. restricting (or moving) applications such as desktop videoconferencing
b. using network devices to ensure that broadcast messages do not go to other networks
c. encouraging the use of applications such as medical imaging
d. sending status information to all computers on all LANs in the backbone network
e. restricting (or moving) applications such as multimedia
25.
Which of the following would not be part of an “ideal” backbone design for the future?
a. access layer composed of 10/100 layer 2 Ethernet switches
b. distribution layer composed of layer 3 Ethernet switches of 100 (or 1000) Base-T
c. redundant switches
d. core layer composed of layer 3 Ethernet switches running 10 (or 40) GbE over fiber
e. coax cabling throughout LANs and BN
26.
The backbone architecture layer that is closest to the users is the
a.) Access layer
b.) Distribution layer
c.) Core layer
d.) Privacy layer
e.) Switched layer
27.
The _______ is the part of the backbone that connects the LANs together.
a.) Access layer
b.) Distribution layer
c.) Core layer
d.) Privacy layer
e.) Switched layer
28.
The _________ is the part of the backbone that connects the different backbones together.
a.) Access layer
b.) Distribution layer
c.) Core layer
d.) Privacy layer
e.) Switched layer
29.
With a switched backbone network, the equipment is usually placed in a ______.
a.) server
b.) NIC
c.) cabinet
d.) basement
e.) rack
30.
Devices in a rack are connected together using ___________.
a.) patch cables
b.) string
c.) servers
d.) modules
e.) chassis switches
31.
Using ______ capabilities, network managers can connect VOIP phones directly into a
VLAN switch and configure the switch to reserve sufficient network capacity so that
they will always be able to send and receive voice messages.
a.) backbone
b.) switched
c.) routed
d.) QoS
e.) access
32.
Computers can be assigned to a VLAN based on the ________.
a.) IEEE 802.1q standard
b.) NIC interface
c.) physical port on the switch
d.) IEEE 802.3 standard
e.) physical location of the computer
33.
The biggest drawbacks to VLANs are their_________________.
a.) cost and management complexity
b.) size and contention
c.) contention and cost
d.) learning curve and contention
e.) speed and size
34.
VLANs prioritize traffic based on the ______.
a.) IEEE 802.1q standard
b.) IEEE 802.11 standard
c.) VLAN size
d.) multiswitch allocation
e.) switch dynamics
35.
Most backbone devices are store-and-forward devices. One simple way to improve
performance is to ensure that they have ________________.
a.) enough ports
b.) sufficient memory
c.) twisted pair connections
d.) large wheels
e.) IEEE 802.11
Short Answer and Essay Questions:
1. What is a backbone network? What is typical of this kind of network?
2. What are some business trends we are seeing in backbone networks?
3. Given network devices such as routers and switches, discuss three major
technological trends that are helpful in explaining the differences between these
devices.
4. When might a router be useful than a switch?
5. List and describe five managerial factors to consider when selecting best practices
for a backbone network design.
6. What are six actions that you might undertake as a network manager to improve
backbone performance?
7. Even though the access layer isn’t part of the backbone, why is it important to the
backbone?
8. What are the main benefits of Virtual LANs?
9. Describe how a VLAN works.