network final Flashcards
(92 cards)
1
Q
PDU stands for
A
Protocol Data Unit
2
Q
LAN stands for
A
Local Area Network
Ex: Mail server, web server
3
Q
Wan stands for
A
Wide Area Network
Ex: The internet
4
Q
Which protocol implements ping requests and replies?
A
ICMP
5
Q
Which layer encapsulates the Network Layer PDU?
A
Data Link
6
Q
Refer to the OSI model, which layer does ARP protocol belong to?
A
2
7
Q
How many functional layers are in the OSI protocol model?
A
7
8
Q
Why do network devices need two layers of addressing? (Ethernet and IP address)?
A
A Network Layer Address is used to forward the packet from one network segment to another network segment. The Data Link Address is used to forward the frame from one device to another within the network segment.
9
Q
Does collision occur between two devices both working on full duplex mode?
A
No
10
Q
What is encapsulation?
A
It is the process of adding a protocol header and sometimes a trailer to a block of application data.
11
Q
What is the basic operation of an Ethernet Switch?
A
Frame arrives at switch port.
Switch looks up MAC Address.
Determines which port to send the frame.
Sends frame.
12
Q
If the default gateway is configured incorrectly on the host, what is the impact on communications?
A
The host can communicate with other hosts on the local network, but is unable to communicate with hosts on remote networks.
13
Q
Which command is used to test connectivity?
A
PING
14
Q
What type of ethernet cable is used to connect a switch port to a computer?
A
Straight through
15
Q
At which layer would a physical address be encapsulated?
A
Data Link Layer
16
Q
What is the correct order of the protocol stack that is used to prepare the request for transmission?
A
HTTP, TCP, IP, Ethernet
17
Q
How many bits does a MAC address have?
A
48 bits (12 HEX)
18
Q
What is the term for a piece of data at any layer of the network model?
A
PDU
19
Q
What is a CONVERGED Network?
A
Delivers voice, video and data to a variety of devices.
20
Q
What are some examples of End Devices?
A
Desktop, Laptop, Printer
21
Q
What are some examples of Intermediary Network Devices?
A
Wireless Router, Switch, Router
22
Q
What does TTL stand for?
A
Time to Live
23
Q
TTL values range from 0 to ?
A
255
24
Q
What is collision domain?
A
Ethernet Switches break up collision
domains into point-to-point links.
25
What is broadcast domain?
Routers break up broadcast domains
| and collision domains.
26
What is Segmentation?
Breaking communication into pieces.
27
What is Multiplexing?
Interleaving the pieces as they traverse the media.
28
What does ARP stand for?
Address Resolution Protocol.
29
How does ARP work?
1. Router1 sends an Ethernet Broadcast message: Who Has IPAddress
2. PC1 responds with its MAC address
3. Router1 sends the frame using Ethernet to PC1 using the MAC address
30
Command to delete ARP table?
arp -d *
31
Command to get MAC address?
ipconfig /all
32
What is the difference between the OSI Reference Model and the
TCP/IP Reference Models for the Protocol Stack?
The TCP/IP Model was developed for the TCP and IP protocols
| whereas the OSI Model is generic.
33
In the context of the protocol stack, what is the difference between a
peer layer conversation and an adjacent layer conversation?
A peer layer conversation occurs between the same functional layer
in the source and destination device. An adjacent layer conversation
occurs between adjacent functional layers in the same device.
34
What is the name of the Protocol Data Unit at the Data Link Layer?
Frame
35
The Data Link layer encapsulates what type of PDU?
Packet
36
What is UTP Cat 6 Ethernet Cable?
Four twisted-pairs of copper wires in an unshielded jacket.
37
What is the “maximum supported bit rate” of a communication
| path/channel called?
Bandwidth
38
What does MAC stand for?
Media access control.
39
What are the three basic parts of a frame?
Header, Data, Trailer
40
Convert the decimal number 237 into hexadecimal notation. Write the hex digits only without the 0x prefix or leading zeros.
ed
41
What is the network address for the following host address: 145.234.135.17 with mask 255.255.192.0?
147.234.128.0/18
42
What is the purpose of the protocol field in the IP header?
It identifies which protocol is used at layer 4.
43
Show the following IPv6 address in uncompressed format.
| 2001:db8:aa20::5b6e:0:1/64
2001:0db8:aa20:0000:0000:5b6e:0000:0001/64
44
What is the most efficient compression of the following IPv6 address:
2001:0000:0000:0000:adf3:0000:0000:0001/64
2001::adf3:0:0:1/64
45
Convert the mask /28 into dotted decimal format.
255.255.255.240
46
For the network ID 223.193.128.0/17, how many host bits need to be borrowed to create 16 subnets?
4
47
Partition the network address 25.34.192.0/18 into subnets of 30 hosts each. What is the ID for subnet 10?
25.34.193.64/27
48
Which of the following is NOT a valid subnet mask?
a. 255.254.240.0
b. 255.255.255.240
c. 248.0.0.0
d. 255.252.0.0
e. 224.0.0.0
e. 224.0.0.0
49
Why are large networks subnetted?
a) to reduce the number of broadcast domains and thereby reduce the broadcast traffic per network segment
b) to align with organizational requirements such as subnet per department.
50
Which statement is the most incorrect regarding private addresses?
a) private addresses are not routable.
b) private addresses can be used by anyone in their private domain.
c) private addresses are dropped by the public internet.
d) private addresses are NATed before being forwarded to the public internet.
e) private addresses were developed to alleviate the problem of IP address exhaustion.
All of them.
51
. Partition the network address 223.134.24.0/23 into 8 subnets. What is the ID for subnet 3? How many valid host addresses are supported per subnet?
223.134.24.192/27
52
Subnet ID 172.16.0.0/26 was partitioned from a classful network. How many bits were borrowed to create this subnet?
10
53
For subnet ID 192.168.15.128/26 what are the first, last and broadcast addresses?
first: 192.168.15.129, last: 192.168.15.190 ,broadcast: 192.168.15.191
54
IP Addresses are added during
| encapsulation at which layer?
3
55
MAC Addresses are added during
| encapsulation at which layer?
2
56
What packet sequence does TCP use to
| set up a connection?
SYN, SYN-ACK,ACK
57
What packet sequence does TCP use to
| take down a connection?
FIN,ACK
58
What does tracert provide that ping does
| not?
List of Routers between source and
| destination.
59
What field in the incoming packet does a
router use to forward it to the outgoing
interface.
IP Destination Address
60
From the Command prompt of your PC, what command can
you use to discover the MAC address of your gateway
interface?
arp -a
61
What are the four message involved in a
| DHCP configuration?
DORA
| Discover, Offer, Request,Ack
62
Which commands are based on the ICMP
| protocol?
Ping and Trace Route (tracert)
63
What are some TCP features?
```
Segmentation
• Connection-Oriented
- Syn-Syn/Ack-Ack;
• Ordered Delivery
Fin-Ack-Fin-Ack
- Sequence Numbers
• Reliable S,ervice
- Acknowledgement
·Flow and Congestion Control
- Window and Rate Control
·Multiplexing
- Ports
```
64
What is in a UDP header?
UDP is a stateless protocol. Neither the sender or the receiver is obligated to
keep track of the state of the comm1unication session.
• Reliability must be handled by the appl cation.
• Live video and voice applications must quickly deliver data and can tolerate
some data loss; they are perfectly suiited to UDP.
• The pieces of communication in UDP are called datagram1s.
• These datagrams are sent
as best-effort by the
transport layer protocol.
• UDP has a low overhead
of 8 bytes.
65
What are the layers of the OSI protocol stack?
```
7 Application
6 Presentation
5 Session
4 Transport
3 Network
2 Data Link
1 Physical
```
66
What are components of a MAC address?
1st 3 bytes are the OUI, last 3 bytes are a unique number
67
Routing is done at which layer?
3
68
What is the purpose of the Sequence Number
andAcknowledgement Numbers in the TCP
and UDP protocols?
Reliability
Segments can be placed in the proper order.
Confirmation that each segment has been
received. Retransmission as required.
69
Identify application layer protocols that use
| TCP and UDP.
TCP
FTP, HTTP, HTTPS, POP3,…
UDP
TFTP, DNS, DHCP, VoIP
70
TTL is found in which network layer?
3
71
HTTP stands for ..?
Hypertext Transfer Protocol
72
What does NAT change when a packet enters
| the external/public network?
Source IP
73
A PC sends a TCP Window size of 0. What does this
| mean?
The PC cannot receive any data
74
Which layer of the OSI model uses
| Ports?
4
75
Which is correct? TCP Packet or TCP Segment
Segment
76
An Application layer Protocol Data
| Unit is called
Data
77
Which OSI layer does an IP address
| belong to?
Layer 3
78
Which OSI layer does a Hub belong
| to?
1
79
Which OSI layer does a Switch belong
| to?
2
80
Which OSI layer does a Router belong
| to?
3
81
A device that moves data between
| networks is a
Router
82
Purpose of ipconfig?
Windows utility to obtain IP usage information.
ipconfig: obtain basic IP configuration information: host IP
address, mask, gateway, MAC address
• ipconfig /all includes additional IP information: DNS, DHCP
server addresses
• ipconfig /flushdns
• ipconfig /release and ipconfig /renew: get updated IP information
83
Purpose of arp?
```
Purpose:
• utility to manage the arp cache.
• Options:
• arp –a: show the arp cache
• arp –d * : delete the contents of the arp cache
• Uses:
• discover the MAC address of devices in the same network
segment
```
84
Purpose of PING
• Purpose:
• utility to send echo request message and obtain response from
any layer 3 connected device. Uses ICMP protocol. (Internet
Control Messaging Protocol)
• Options:
• ping ipaddr: send an echo request to ipaddr
• Ping ipaddr -t: continuously send a ping to ipaddr
• Uses:
• Verify a layer 3 path to an end device such as a gateway router
• Simple assessment of packet delay and packet loss
85
Purpose of tracert?
Purpose:
• utility to identify the layer 3 path to a destination device.
• Uses ICMP Protocol
• Options:
• tracert ipaddr: show the layer 3 path to ipaddr
• Uses:
• show the layer 3 path
• identify elements of the routing table
• identify number of routers in the path to the destination
86
Netstat
• Purpose:
• utility to display TCP connections including source and
destination sockets.
• Options:
• netstat: show TCP connections
• netstat –n: show the TCP connections using numeric addresses
87
nslookup
```
Purpose:
• utility to query the DNS server.
• Options:
• nslookup URL: translate the URL into an IP address
• Uses:
• verify DNS configuration
• get IP information
• verify connectivity to DNS server
```
88
route print
Purpose:
• Windows Utility to show node routing table
• Options:
• route print
89
Carrier indicator (Link Light)
```
Purpose:
• Verify physical connection.
• Options:
• Observer carrier indication on Ethernet port
• Uses:
• Verify cable connection and integrity
• Verify NIC
```
90
Network Design
```
Data Network
• Management
• Observable
• Controllable
• Security
• Resiliency
• Survive Single Points of Failure
• Performance and Capacity
• Delay, Loss, Jitter
• Traffic Volume (Packets per Second)
```
91
Network Operations
```
Monitoring and Control
• Troubleshoot and Repair
• Failure
• Performance
• Forecasts and Upgrades
• Features
• Growth
• Technology
• Backup and Restore
```
92
nslookup
nslookup is a network administration command-line tool available for many computer operating systems for querying the Domain Name System to obtain domain name or IP address mapping or for any other specific DNS record.
