If a technician wants to test network connectivity, which basic command should be used.. When a network administrator wants to verify the application layer software between source and de
Trang 1Chapter 18
1. When a technician performs basic testing of a network, which of the following
is true?
A The technician should proceed in sequence from one OSI reference model layer to the next.
2. What approach should a technician start with when he/she troubleshoots a
network?
A The technician should start with a structured approach.
3. When a technician troubleshoots a problem on a network, which layer of the
OSI model should he/she begin with?
A Begin with Layer 1
4. If a technician wants to test network connectivity, which basic command should
be used?
B ping
5. When a network administrator wants to verify the application layer software
between source and destination stations, which of the following commands should be used?
B telnet
6. You suspect that one of the routers connected to your network is sending bad
routing information What command can you use to check?
B router# show ip route
7. Why would you display the IP routing table?
D To set the parameters and filters for the router
8. If you wanted to see RIP routing updates as they are sent and received, what
command structure would you use?
C router# debug ip rip
9. The dynamic output of the debug command comes at a performance cost, which
A High
10. By default, the router sends the debug output and system messages to what?
A The console
Trang 211. The telnet command provides what type of terminal?
B Virtual
12. ICMP stands for what?
C Internet Control Message Protocol
13. Most interfaces or NICs have what type of lights that show whether there is a valid connection?
A Indicator
14. Telnet is used at what layer of the OSI reference model?
D Layer 7
15. If the routing protocol is not enabled or the IP address cannot be determined, at which layer of the OSI model should an administrator begin to look?
C Layer 3
Chapter 19
1. Which of the following best describes TCP/IP?
A It is a suite of protocols that can be used to communicate across any set of interconnected networks.
2. Which of the following is one of the protocols found at the transport layer?
B UDP
3. What is the purpose of port numbers?
A They keep track of different conversations crossing the network at the same time.
4. Which of the following best describes UDP?
D A protocol that exchanges datagrams without acknowledgments or guaran-teed delivery
5. Which of the following TCP/IP layers includes file transfer, e-mail, remote login, and network management?
B Application
6. Why are TCP three-way handshake/open connections used?
A To ensure that lost data can be recovered if problems occur later
Trang 37. What does a TCP sliding window do?
C It allows the window size to be negotiated dynamically during the TCP session, which results in more efficient use of bandwidth.
8. UDP segments use what protocols to provide reliability?
B Application layer protocols
9. Which of the following best describes window size?
B The number of messages or bytes that can be transmitted while awaiting an acknowledgment
10. What is the function of ARP?
C It is used to map an IP address to a MAC address.
Chapter 20
1. Common ACL functions include filtering packets internally, protecting the
inter-nal network from illegal Internet access, and restricting access to virtual termiinter-nal ports True or false?
A True
2. ACL is an acronym for:
D Access control list
3. A(n) ACL works by comparing the source IP address against the
ACL rules
C Standard
4. A(n) ACL works by comparing the source IP address, destination
IP address, or other parameters against the ACL rules
A Extended
5. A(n) ACL uses names instead of numbers to distinguish ACLs
B Named
6. As a general rule, ACLs should be placed where in the network?
C Closest to the traffic to be controlled
Trang 47. In a firewall architecture, which router most likely will be configured with an ACL?
C The exterior router
8. Named ACLs were introduced in Cisco IOS 11.2 True or false?
B False
9. What command is used to apply an ACL to a VTY port?
A ip access-list
10. Which of the following commands would you use to find out whether any ACLs are set on an interface?
C show ip interface
11. What do you call the additional 32 bits of information in the access-list statement?
A Wildcard bits
12. If you want to permit traffic based on its addressing or protocol type, you would use which of the following commands?
B Router (config)#access-list access-list number {permit | deny} {test conditions}
13. Standard IP access lists permit or deny routing of a packet based on the IP address that it originates from and the protocol suite that it is destined for True or false?
A True
14. Access lists impact network security based on which of the following factors?
C The source subnet/host/network of the packets
15. What type of networking device would be needed to implement access lists to increase network security?
B Router
16. What does the following access list allow? access-list 1 permit 204.211.19.162
0.0.0.0
B “Permit a specific host.”
Trang 5Answers to Hints in Appendix A
What is the purpose of this floor?
Answer: Warehouse, reception area
What door will workers move freight through?
Answer: The large garage doors at the rear of the building
What doors will visitors come in?
Answer: Front doors off lobby that has reception station in it.
Where are visitors most likely to go after they sign in?
Answer: The conference room adjacent to the reception area
Where would you consider using wireless technology?
Answer: Guests could log on to the Internet via wireless in the reception and
conference areas Warehouse staff could use wireless for inventory.
If your department someday is tasked with wiring IP security cameras, what areas
would you want to keep under surveillance?
Answer: The two secure storage areas, the rear walkthrough door, and the
reception area
From where does the telephone company serve this building?
Answer: There is a point of presence [POP] next to the mechanical room.
What kind of lock should it have?
Answer: A good one that can be opened from the inside
Would the POP be a good place for the servers?
Answer: Possibly—it is certainly big enough and is close to the elevators, for easy
access.
If it is determined that the server room must exist separate from the POP, what
consid-erations should guide its location?
Answer: The location should be in a TR and should be on a middle floor.
Could you install the risers in the POP?
Answer: No Check the floor above, and you will see that it has a conference room
in that position.
Where might you install the risers?
Answer: There is a small hallway adjacent to each stairway Check that out.
Trang 6The horizontal cabling always should go parallel to walls Getting to Room 1.2 while staying parallel to walls makes a cable run of how many meters? Is this useable?
Answer: The distance is about 94 meters This is barely enough to make the run, go down the walls, and join a work-area connector The designer must decide whether
to cheat a little bit or to take advantage of the wireless system that is installed for the warehouse or conference room This would present a security hassle but would solve a major problem.
Where might you put the telecommunications room on Floor 2? You might consider using two of them
Answer: Room 2.31 because it offers ceiling access to Room 3.10 above and to the mechanical room below You might need to add one at Room 2.7 to accommodate the offices against that wall.
Floor 3 has large unplanned spaces in Rooms 3.1 and 3.2 If you place the telecommu-nications room in Room 3.10, how can you serve these spaces, especially the far side
of Room 3.2?
Answer: Wireless is a good solution for now Then when the rooms are built out, put a second telecommunications room in either of them.
You notice a large deck on Floor 4, as well as a banquet area with a piano What would you need to provide network connectivity to this area?
Answer: You would need only one TR and some wireless to serve this area.
Where will you put the TR?
Answer: This is tough Room 4.5 seems to be an office However, Room 4.8 is blank Also, there is a hallway with an exterior door shown next to the staircase by Room 4.10 Because this is the fourth floor, you suspect an error Furthermore, Room 4.10 is shown with a door facing into a stairwell Chances are, you could mention these apparent errors and at the same time request that a TR be installed between Rooms 4.4 and 4.5.
Trang 9Numerics
4B/5B encoding, 329
5-4-3 rule, 216, 320
8B1Q4 encoding, 339
10BASE2, 321–322
10BASE5, 320–321
10BASE-T, 322–323, 325
architecture, 326–328
link pulse, 323
10-Gbps Ethernet, 347–350
architecture, 350, 352–353
10-Mbps Ethernet, 317
5-4-3 rule, 320
line encoding, 318
Manchester encoding, 318
100BASE-FX, 328, 332–334
100BASE-T, 329, 331–332
100BASE-TX, 328
110-blocks, 938
802.1X/EAP, 224–225
1000BASE-LX, 342–344
1000BASE-SX, 342–345
1000BASE-T, 339–342
1000-Mbps Ethernet, 337–339
A
AAA servers, 90
absorption, 150
AC voltage, 119
access methods, CSMA/CD, 268, 271
backoff algorithm, 276
access VPNs, 56
accessing
CLI on Cisco IOS routers, 566–569 global configuration mode, 593
acknowledgments, 485
PAR, 826–827
ACLs, 841–842
configuring, 847 extended, 855–861
defaults, 862–863 ICMP configuration, 861–862
functions of, 843
bit buckets, 845
named, 863–867
on firewall routers, 868 restricting vty access, 869–870 standard, 852–854
verifying, 870–871
active hubs, 218
ad hoc networks, 162 ADA (Americans with Disabilities Act), 901 adapter cards, NICs, 12–13
modem installation, 13–14
Address field (Ethernet frames), 261 address mask requests, 777–778 administrative distance, 683–684, 724 alien crosstalk, 196
alignment errors, 284–285 all band interference, 169 Alohanet, 252
always-on services, 15 amplitude, 184 analog bandwidth, 66, 190
Trang 10debug ip packet detail command output, 807–808
debug ip rip command output, 806–807
AND operator, 31
ANDing, 463, 465
angle of incidence, 137
angle of reflection, 137
any wildcard, 850–851
application layer (OSI model), 71, 491
connection establishment/termination, 493–494
direct network applications, 492
DNS, 494–495
FTP, 495–496
HTTP, 496–497
indirect network support, 492–493
SMTP, 497–498
SNMP, 498
TCP/IP model, 377–378
Telnet, 499–500
troubleshooting, 797–798
applications, 18
applying
descriptions to interfaces, 604–605
passwords to Telnet sessions, 596
APs (access points), 164
wireless, 92
architecture
of 10-Gbps Ethernet, 350–353
of Fast Ethernet, 334–337
of Gigabit Ethernet, 345–347
of Internet, 383–385
scalability, 385
of TBASE-T, 326–328
ARP (Address Resolution Protocol), 408, 834
default gateways, 411
operation within subnets, 410
ASCII (American Standard Code for Information
Interchange), 19
assigned port numbers for services, 831–832
assignment of IP addresses, 407
BOOTP assignment, 414–415
DHCP assignment, 415–417 RARP assignment, 412–414 static assignment, 408
ATM (Asynchronous Transfer Mode), cell switching, 523 atoms, 115
Bohr model, 116 electrons, 117
attacks, preventing DoS attacks during synchronization, 823
attenuation, 195–196 AUI connectors, 210 authentication on WLANs, 166–168 autonegotiation, 285
FLP bursts, 287
autonomous systems, 443, 539, 692 availability
quantifying, 514 uptime, 513
B
backbone cabling, 893–894
fiber-optic, 894–896
backbone tree topology, 98 backing up configuration files, 608 backoff algorithms, 269, 276 backplane, 10
balanced hybrid routing protocols, 692, 701 bandwidth, 58, 233, 442
analog, 190 characteristics of, 58 data transfer calculations, 64–66 digital, 191
versus analog, 66
highway analogy, 59 limitations of, 61–63 measurements of, 61 pipe analogy, 59 throughput, 64
bandwidth domains, 81