final Flashcards
1
Q
An IPv4 address is __________ bits long.
A
32
2
Q
An IPv4 address is normally represented in base ____ or dotted-decimal notation.
A
265
3
Q
In classful addressing, the IPv4 address space is divided into __________ classes.
A
5
4
Q
In class A, the netid is between ______________.
A
0 to 127
5
Q
In class B, the netid is between ______________.
A
128 to 191
6
Q
In class C, the netid is between ______________.
A
192 to 223
7
Q
The default mask for class A is ______________.
A
255.0.0.0
8
Q
The default mask for class B is ______________.
A
255.255.0.0
9
Q
The default mask for class C is ______________.
A
255.255.255.0
10
Q
The default mask for class D is ______________.
A
doesnt have default mask because it is used for multicast
11
Q
The default mask for class E is ______________.
A
doesnt have default mask because it is used for experimental/research
12
Q
In classless addressing, __________ is assigned to a organization.
A
a variable-length block
13
Q
The number of addresses assigned to an organization in classless addressing _______.
A
must be a power of 2
14
Q
The first address assigned to an organization in classless addressing
A
must be evenly divisible by the number of addresses
15
Q
Which address could be the beginning address of a block of 32 classless addresses?
A
2.4.6.64
because 32 divides 64 evenly
16
Q
Which address could be the beginning address of a block of 16 classless addresses?
A
the last byte must be evenly divisible by 16
17
Q
Which address could be the beginning address of a block of 256 classless addresses?
A
2.4.6.0
because ip uses base 256 arithmetic, the last byte must be 0…. meaning the total address is divisible by 256
18
Q
What is the first address of a block of classless addresses if one of the addresses is 12.2.2.76/27?
A
12.2.2.64
19
Q
What is the first address of a block of classless addresses if one of the addresses is 12.2.2.76/10?
A
12.0.0.0
20
Q
What is the first address of a block of classless addresses if one of the addresses is 12.2.2.127/28?
A
12.2.2.112
21
Q
Find the number of addresses in a block of classless addresses if one of the addresses is 12.2.2.7/24.
A
256
22
Q
Find the number of addresses in a block of classless addresses if one of the addresses is 12.2.2.7/30.
A
4
23
Q
What is the last address of a block of classless addresses if one of the addresses is 12.2.2.127/28?
A
12.2.2.127
24
Q
What is the last address of a block of classless addresses if one of the addresses is 12.2.2.6/30?
A
12.2.2.7
25
In fixed-length subnetting, the number of subnets must _______.
be a power of 2
26
An organization is granted a block; one address is 2.2.2.64/20. The organization needs 10 subnets. What is the subnet prefix length?
/24
27
An organization is granted a block; one address is 2.2.2.64/25. If the subnet prefix length is /28, what is the maximum number of subnets?
8
28
An organization is granted a block of classless addresses with the starting address 199.34.76.64/28. How many addresses are granted?
16
29
An organization is granted a block of classless addresses with the starting address 199.34.76.128/29. How many addresses are granted?
8
30
An organization is granted a block of classless addresses with the starting address 199.34.32.0/27. How many addresses are granted?
32
31
What is the default mask for class A in CIDR notation?
/8
32
What is the default mask for class B in CIDR notation?
/16
33
What is the default mask for class C in CIDR notation?
/24
34
In ________ addressing, when an address is given, we can find the beginning address and the range of addresses.
classful
35
In classless addressing, the ______ is another name for the common part of the address range.
prefix
36
In classless addressing, the _______ is the varying part (similar to the hostid).
suffix
37
In classless addressing, the prefix length defines the _____________.
mask
38
In a block, the prefix length is /22; what is the mask?
255.255.252.0
39
In a block, the prefix length is /15; what is the mask?
255.254.0.0
40
In a block, the mask is 255.255.192.0; what is the prefix length?
/18
41
In a block, the mask is 255.255.255.224; what is the prefix length?
/27
42
In _______ delivery, both the deliverer of the IP packet and the destination are on the same network.
a direct
43
In _______ delivery, the deliverer of the IP packet and the destination are on different networks.
an indirect
44
In classful addressing, when a direct delivery is made, both the deliverer and receiver have the same _______.
netid
45
In classful addressing, when an indirect delivery is made, the deliverer and receiver have _______.
different netids
46
In _______ forwarding, the full IP address of a destination is given in the routing table.
host-specific
47
In _______ forwarding, the mask and destination addresses are both 0.0.0.0 in the routing table.
default
48
In _______ forwarding, the destination address is a network address in the routing table.
network-specific
49
In _______ forwarding, the routing table holds the address of just the next hop instead of complete route information.
next-hop
50
In ________ addressing, a typical forwarding module can be designed using three tables, one for each unicast class (A, B, C).
classful
51
In classful addressing, the class of the address can be found by shifting the copy of the address ____ bits to the right.
28
52
In classful addressing we need a routing table with at least ______ columns.
3
53
In classless addressing, we need a routing table with at least _______ columns.
4
54
The idea of address aggregation was designed to alleviate the increase in routing table entries when using ________.
classless addressing
55
The principle of ________ states that the routing table is sorted from the longest mask to the shortest mask.
longest mask matching
56
The use of hierarchy in routing tables can ________ the size of the routing tables.
reduce
57
_______ deals with the issues of creating and maintaining routing tables.
Routing
58
A _______ routing table contains information entered manually.
static
59
A _______ routing table is updated periodically using one of the dynamic routing protocols.
dynamic
60
The input and output ports of a router perform the ________ layer functions of the router.
physical and data link
61
The routing processor of a router performs the ________ layer functions of the router.
network
62
The task of moving the packet from the input queue to the output queue in a router is done by _________.
switching fabrics
63
The ________ protocol is the transmission mechanism used by the TCP/IP suite.
IP
64
IP is _________ datagram protocol.
both unreliable and connectionless
65
The term ________ means that IP provides no error checking or tracking. IP assumes the unreliability of the underlying layers and does its best to get a transmission through to its destination, but with no guarantees.
best-effort delivery
66
A best-effort delivery service such as IP includes _______.
no error checks/corrections
| no datagram acknowledgement
67
An HLEN value of decimal 10 means _______.
there are 40 bytes in the header
68
If the fragment offset has a value of 100, it means that _______.
the first byte of the datagram is byte 800
69
What is needed to determine the number of the last byte of a fragment?
both offset number and the total length
70
The IP header size _______.
is 20 to 60 bytes long
71
Packets in the IP layer are called _________.
datagrams
72
The total length field defines the total length of the datagram _________.
including the header
73
When a datagram is encapsulated in a frame, the total size of the datagram must be less than the _______.
MTU
74
Which IP option is used if exactly four specific routers are to be visited by the datagram?
strict source route
75
For the timestamp option, a flag value of _______ means that each visited router adds only the timestamp in the provided field.
0
76
The IP header field formerly known as the service type field is now called the _______ field.
differentiated services
77
The _______ module takes fragments of a message and puts them back in order.
reassembly
78
The _______ module sends out an IP packet, the next-hop address, and interface information.
forwarding
79
The _______ module discards datagrams with a TTL value of zero.
processing
80
The output of the _______ module is an IP packet destined for an upper-layer protocol.
reassembly
81
The _______ module consults the MTU table to determine the packet size necessary for transmission.
fragmentation
82
The value of the ________ subfield in an option controls the presence of the option in fragmentation.
copy
83
The value of the ________ subfield defines the general purpose of an option.
class
84
The value of the ________ subfield defines the types of an option.
number
85
Only ______ end of option option can be used in a datagram.
one
86
When we use IP over ATM, only the ________ cell carry(ies) the 8-byte trailer added to the IP datagram.
last
87
When we use IP over ATM, padding can be added only to the _____ or the _______.
last cell; last two cells
88
To find the physical address of the exiting-point router, ATM uses the services of _________.
ATMARP
89
The inverse request and inverse reply messages can bind the physical address to an IP address in a(n) _______ situation.
PVC
90
The request and reply message can be used to bind a physical address to an IP address in a(n) _______ situation.
SVC
91
__________ allows an ATM network to be divided into several logical subnets.
LIS
92
A _______ address is an internetwork address with universal jurisdiction.
logical
93
The logical addresses in the TCP/IP protocol suite are called _______ addresses.
IP
94
A ________ is a local address. Its jurisdiction is over a local network.
physical
95
If the sender is a host and wants to send a packet to another host on the same network, the logical address that must be mapped to a physical address is ______.
the destination IP address in the datagram header
96
If the sender is a host and wants to send a packet to another host on another network, the logical address that must be mapped to a physical address is ______.
the IP address of the router found in the routing table
97
The sender is a router that has received a datagram destined for a host on another network. The logical address that must be mapped to a physical address is ______.
the IP address of the router found in the routing table
98
The sender is a router that has received a datagram destined for a host in the same network. The logical address that must be mapped to a physical address is ______.
the destination IP address in the datagram header
99
In _______, a table associating a logical address with a physical address is updated manually.
static mapping
100
The target hardware address on an Ethernet is _______ in an ARP request.
0x000000000000
101
An ARP reply is normally _______.
unicast
102
An ARP request is normally _______.
broadcast
103
technique called ______ is used to create a subnetting effect.
proxy ARP
104
A _______ is an ARP that acts on behalf of a set of hosts.
proxy ARP
105
For purposes of routing, the Internet is divided into ___________.
autonomous systems
106
Routing inside an autonomous system is referred to as ________ routing.
intradomain
107
Routing between autonomous systems is referred to as ______ routing.
interdomain routing
108
In _______ routing, the least cost route between any two nodes is the route with the minimum distance.
distance vector
109
In ________, each node maintains a vector (table) of minimum distances to every node.
distance vector
110
In distance vector routing, each node periodically shares its routing table with _________ and whenever there is a change.
its immediate neighbors
111
The Routing Information Protocol (RIP) is an intradomain routing based on _________ routing.
distance vector
112
The metric used by _______ is the hop count.
RIP
113
In RIP, the ________ timer controls the advertising of regular update messages.
periodic
114
In RIP, the ________ timer is used to purge invalid routes from the table.
garbage collection
115
In RIP, the ________ timer controls the validity of the route.
expiration
116
RIP uses the services of _______.
UDP
117
The _________ routing uses the Dijkstra algorithm to build a routing table.
link state
118
The Open Shortest Path First (OSPF) protocol is an intradomain routing protocol based on _______ routing.
link state
119
The _______ protocol allows the administrator to assign a cost, called the metric, to each route.
OSPF
120
In OSPF, a ________ link connects two routers without any other host or router in between.
point-to-point
121
In OSPF, a _______ link is a network with several routers attached to it.
transient
122
In OSPF, a ________ link is a network is connected to only one router.
stub
123
In OSPF, a ________ defines the links of a true router.
router link
124
In OSPF, a ________ defines the links of a network.
network link
125
In OSPF, an area border router advertises a ____________ LSA.
summary link to network
126
In OSPF, the ________ message does not contain complete database information; it only gives an outline, the title of each line in the database.
database description
127
In OSPF, a _________ message is sent by a router that needs information about a specific route or routes.
link state request
128
In ________ routing, we assume that there is one node (or more) in each autonomous system that acts on behalf of the entire autonomous system.
path vector
129
___________ is an interdomain routing protocol using path vector routing.
BGP
130
BGP can have two types of sessions: _______ and ________ sessions.
E-BGP; I-BGP
131
To create a neighborhood relationship, a router running BGP sends a(n) ________ message.
open
132
In BGP, the _______ message is used by a router to withdraw destinations that have been advertised previously, or to announce a route to a new destination, or both.
update
133
The routers running the BGP protocols exchange _______ messages regularly to tell each other that they are alive.
keepalive
134
BGP messages are encapsulated in _______.
TCP segments
135
An area is _______.
part of an AS
136
ICMP is a _________ layer protocol.
network
137
An ICMP message has _____ header and a variable-size data section.
an 8-byte
138
Which of the following is true about ICMP messages?
1. An ICMP error message may be generated for an ICMP error message.
2. An ICMP error message may be generated only for the first fragment.
3. An ICMP error message may be generated for a multicast datagram.
An ICMP error message may be generated only for the first fragment.
139
Which of the following is true about ICMP messages?
1. An ICMP error message may be generated for an ICMP error message.
2. An ICMP error message may be generated only for each fragment.
3. No ICMP error message will be generated for a datagram having a special address such as 127.0.0.0 or 0.0.0.0.
No ICMP error message will be generated for a datagram having a special address such as 127.0.0.0 or 0.0.0.0.
140
If a host needs to synchronize its clock with another host, it sends a _______ message.
timestamp-request
141
The purpose of echo request and echo reply is to _______.
check node-to-node communication
142
In error reporting the encapsulated ICMP packet goes to _______.
the original sender
143
What field uniquely identifies the kind of ICMP message (for example, echo reply versus echo request)?
type
144
When the hop-count field reaches zero and the destination has not been reached, a _______ error message is sent.
time-exceeded
145
When all fragments of a message have not been received within the designated amount of time, a _______ error message is sent.
time-exceeded
146
Errors in the header or option fields of an IP datagram require a _______ error message.
parameter-problem
147
A _______ can learn about network _______ by sending out a router-solicitation packet.
host, routers
148
Who can send ICMP error-reporting messages?
routers or destination hosts
149
One method to alert a source host of congestion is the _______ message.
source-quench
150
A time-exceeded message is generated if _______.
the round-trip time between hosts is close to zero and fragments of a message do not arrive within a set time
151
To determine whether or not a node is reachable, _______ message can be sent.
an echo-request
152
In calculating the time difference between two clocks, a negative value indicates _______.
the destination clock lags behind the source clock
153
An IP datagram (datagram A) cannot reach its destination. An ICMP error message is sent to the source. The data field of the IP datagram (datagram B) that encapsulates the ICMP packet contains _______.
the ICMP header plus 8 bytes of datagram A
154
One of the main duties of the transport layer is ____________ communication.
process-to-process
155
The client program normally uses ____________ port number.
an ephemeral
156
The server program normally uses __________ port number.
a well-known
157
A socket address is a combination of __________.
1. Mac address and logical address
2. Mac address and port number
3. User-specific address and logical address
None of the choices are correct
158
______________ means accepting items from more than one source.
Multiplexing
159
______________ means delivering items to more than one source.
Demultiplexing
160
_________ means the producer delivers the items when they are produced without waiting for the request from the consumer.
Pushing
161
_________ means the consumer takes the items when it is ready to do so.
Pulling
162
In the stop-and-wait protocol, the send window size is ______ and the receive window size is _______ where n is related to the number of bits in the sequence.
1, 1
163
In the go-back-N protocol, the send window size is ______ and the receive window size is _______, where n is related to the number of bits in the sequence. number.
n, 1
164
In the selective-repeat protocol, the send window size is ______ and the receive window size is _______, where n is related to the number of bits in the sequence.
n, n
165
UDP is called a ________________transport protocol.
connectionless, unreliable
166
UDP does not add anything to the services of IP except for providing _______ communication.
process-to-process
167
UDP is an acronym for _______.
User Datagram Protocol
168
The local host and the remote host are defined using IP addresses. To define the processes, we need second identifiers called ____________ .
port addresses
169
The ports ranging from 0 to 1,023 are assigned and controlled by ICANN. These are the ___________ ports.
well-known
170
The ports ranging from 1,024 to 49,151 are called ___________ ports.
registered
171
The ports ranging from 49,152 to 65,535 can be used as temporary or private port numbers. They are called the ________ ports.
dynamic
172
In the sending computer, UDP receives a data unit from the _______ layer.
application
173
In the sending computer, UDP sends a data unit to the _______ layer.
IP
174
UDP and TCP are both _______ layer protocols.
transport
175
Which of the following functions does UDP perform?
process-to-process communication
176
When the IP layer of a receiving host receives a datagram, _______.
a transport layer protocol takes over
177
UDP needs the _______ address to deliver the user datagram to the correct application process.
port
178
A port address in UDP is _______ bits long.
16
179
Which of the following does UDP guarantee?
1. flow control
2. connection-oriented delivery
3. flow control
None of the choices are correct
180
The source port address on the UDP user datagram header defines _______.
the process running on the sending computer
181
The combination of an IP address and a port number is called a ____________.
socket address
182
To use the services of UDP, we need ________ socket addresses.
two
183
UDP packets are called __________ .
user datagrams
184
UDP packets have a fixed-size header of _______ bytes.
8
185
UDP packets are encapsulated in ___________ .
an IP datagram
186
UDP uses ________ to handle outgoing user datagrams from multiple processes on one host.
multiplexing
187
UDP uses _______ to handle incoming user datagrams that go to different processes on the same host.
demultiplexing
188
TCP is a __________protocol.
stream-oriented
189
TCP groups a number of bytes together into a packet called a ___________.
segment
190
TCP is a(n) ___________ protocol.
connection-oriented
191
TCP is a(n) _______ transport protocol.
reliable
192
TCP uses _________________ to check the safe and sound arrival of data.
an acknowledgment mechanism
193
The bytes of data being transferred in each connection are numbered by TCP. The numbering starts with a __________________.
randomly generated number
194
TCP assigns a sequence number to each segment that is being sent. The sequence number for each segment is the number of the _______ byte carried in that segment.
first
195
Communication in TCP is ___________.
full-duplex
196
The value of the acknowledgment field in a segment defines the sequence number related to the ______byte a party expects to receive.
next
197
The inclusion of the checksum in the TCP segment is ________.
mandatory
198
A TCP segment is encapsulated in __________.
an IP datagram
199
A SYN segment cannot carry data; it consumes _____ sequence number(s).
one
200
A SYN + ACK segment cannot carry data; it consumes _____ sequence numbers.
1. no
2. three
3. two
None of the choices are correct
201
An ACK segment, if carrying no data, consumes ______ sequence number(s).
no
202
The connection establishment procedure in TCP is susceptible to a serious security problem called the _________ attack.
SYN flooding
203
The SYN flooding attack belongs to a group of security attacks known as a _____ attack.
denial of service
204
The FIN segment consumes ____ sequence numbers if it does not carry data.
1. two
2. three
3. no
None of the choices are correct
205
The FIN + ACK segment consumes _____ sequence number(s) if it does not carry data.
one
206
In TCP, one end can stop sending data while still receiving data. This is called a ______.
half-close
207
A(n) _________ machine is a machine that goes through a limited number of states.
finite state
208
A common value for MSL is between___ seconds and ___ minute(s).
30; 1
209
To accomplish flow control, TCP uses a ___________ window protocol.
sliding
210
TCP sliding windows are __________ oriented.
byte
211
In TCP, the size of the send window is the ________ of rwnd and cwnd.
minimum
212
In TCP, the window should not be _________.
shrunk
213
In TCP, the receiver can temporarily shut down the window; the sender, however, can always send a segment of _____ byte(s) after the window is shut down.
one
214
A serious problem can arise in the sliding window operation when either the sending application program creates data slowly or the receiving application program consumes data slowly, or both. This problem is called the ______.
silly window syndrome
215
Nagle's algorithm can solve the silly window syndrome created by the _________.
sender
216
Clark's solution can solve the silly window syndrome created by the _________.
receiver
217
Delayed acknowledgment can solve the silly window syndrome created by the _________.
receiver
218
ACK segments consume _______ sequence number(s) and _______ acknowledged.
no; are not
219
In modern implementations of TCP, a retransmission occurs if the retransmission timer expires or ________ duplicate ACK segments have arrived.
three
220
In TCP, ________ retransmission timer is set for an ACK segment.
no
221
Lost acknowledgments may create a _______ if they are not handled properly.
deadlock
222
In the ________ algorithm the size of the congestion window increases exponentially until it reaches a threshold.
slow start
223
In the __________ algorithm the size of the congestion window increases additively until congestion is detected.
congestion avoidance
224
In the congestion detection algorithm, if detection is by a time-out, a new _______ phase starts.
slow start
225
In the congestion detection algorithm, if detection is by three ACKs, a new _______ phase starts.
congestion avoidance
226
In TCP, there can be ______ RTT measurement(s) in progress at any time.
only one
227
The value of the window scale factor can be determined during __________.
connection establishment
228
Multiply the header length field by _______ to find the total number of bytes in the TCP header.
4
229
Urgent data requires the urgent pointer field as well as the URG bit in the _______ field.
control
230
The options field of the TCP header ranges from 0 to _______ bytes.
40
231
Which option defines the maximum number of bytes in a TCP segment?
maximum segment size
232
If the ACK value is 200, then byte _______ has been received successfully.
199
233
The _______ timer prevents a long idle connection between two TCPs.
keepalive
234
The _______ timer is needed to handle the zero window-size advertisement.
persistence
235
Karn's algorithm is used in calculations by the _______ timer.
retransmission
236
A special segment called a probe is sent by a sending TCP when the _______ timer goes off.
persistence
237
VPN technology uses two simultaneous techniques to guarantee privacy for an organization: ________ and ___________.
IPSec; tunneling
238
Tunneling is a technique in which the IP datagram is first _______ and then _______.
encrypted; encapsulated in another datagram
239
IP Security (IPSec) is a collection of protocols designed by the IETF (Internet Engineering Task Force) to provide security for a packet at the _________ level.
network
240
IPSec requires a logical connection between two hosts using a signaling protocol called ____________.
SA
241
IPSec operates at two different modes: _________ mode and _________mode.
transport; tunnel
242
In the _________ mode, the IPSec header is added between the IP header and the rest of the packet.
transport
243
In the ________ mode, the IPSec header is placed in front of the original IP header.
tunnel
244
IPSec defines two protocols: _________ and __________.
1.AH: SSP
2. ESP; SSP
3. AH: EH
None of the choices are correct
245
The ________ protocol is designed to authenticate the source host and to ensure the integrity of the payload carried by the IP packet.
AH
246
The _______ protocol provides message authentication and integrity, but not privacy.
AH
247
The _______ protocol provides message authentication, integrity, and privacy.
ESP
248
The _______ was designed to provide security at the transport layer.
TLS
249
_______ was invented by Phil Zimmermann to provide all four aspects of security in the sending of email.
1. AH
2. ESP
3. TLS
None of the choices are correct
250
A packet-filter firewall filters at the ________ or ___________ layer.
network; transport
251
A proxy firewall filters at the __________ layer.
application
252
In __________cryptography, the same key is used by the sender (for encryption) and the receiver (for decryption).
symmetric-key
253
In _________ cryptography, the same key is used in both directions.
symmetric-key
254
_________ cryptography is often used for long messages.
Symmetric-key
255
___________ cryptography is often used for short messages.
Asymmetric-key
256
__________means that the sender and the receiver expect confidentiality.
1. Non-repudiation
2. Integrity
3. Authentication
None of the choices are correct
257
___________ means that the data must arrive at the receiver exactly as they were sent.
Message integrity
258
______________ means that the receiver needs to be sure of the sender identity and that an imposter has not sent the message.
Message authentication
259
______________ can provide authentication, integrity, and nonrepudiation for a message.
Digital signature
260
Digital signature does not provide _________.
privacy
261
In ___________, the entity identity is verified once for the entire duration of system access.
entity authentication
262
In __________ cryptography, everyone has access to everyone's public key.
asymmetric-key
263
After a message is encrypted, it is called _______.
ciphertext
264
If 20 people need to communicate using symmetric-key cryptography, _______ symmetric keys are needed.
190
265
In the asymmetric-key method of cryptography, which key is publicly known?
encryption key only
266
In the asymmetric-key method of cryptography, the receiver has possession of the _______.
private key
267
The RSA algorithm uses _______ cryptography method.
an asymmetric-key
268
If user A wants to send an encrypted message to user B, the plaintext is encrypted with the public key of _______.
user B
269
In the digital signature technique when the whole message is signed using an asymmetric key, the sender of the message uses _______ to sign the message.
his or her own private key
270
In the digital signature technique when the whole message is signed using an asymmetric key, the receiver of the message uses _______ to verify the signature.
the sender's public key
271
A _______ is a trusted third party that solves the problem of symmetric-key distribution.
KDC
272
A _______ certifies the binding between a public key and its owner.
CA
