Chapter 2: Network Models Flashcards
A MAC address is known as a(n) ____ address.
physical
A NIC sends data in discrete chunks called ______.
frames
An IP address is also known as a _______ address.
logical
Any device that deals with a MAC address is part of which layer of the OSI model?
Data Link (Layer 2)
Anything that deals with pure IP packets (getting an IP packet to its destination) sits in the _______ layer.
Internet
How much data can a typical frame hold?
1500 bytes
In the TCP/IP model, any part of the network that deals with complete frames is in the ______ layer.
Link
Is TCP connection-oriented or connectionless?
Connection-oriented
Is UDP connection-oriented or connectionless?
Connectionless
What are segments/datagrams given to help the receiving system know the total # of segments/datagrams and how to put them together?
Sequencing Numbers
What are the chunks of data called at the Network Layer (Layer 3)?
Packets
What are the first 3 tuples of a MAC address called?
The last 3?
-Organizationally Unique Identifier (OUI)
What are the four layers of TCP/IP?
4) Application
3) Transport
2) Internet
1) Link/Network Interface
What are the seven layers of the OSI model?
7) Application
6) Presentation
5) Session
4) Transport
3) Network
2) Data Link
1) Physical
What are the two sublayers of the Data Link Layer?
1) Logical Link Control (LLC)
2) Media Access Control (MAC)
What are the two unique identifiers that each system has in a TCP/IP network?
1) IP address
2) MAC address
What device uses IP addresses?
Router
What does a NIC do if it doesn’t know the MAC address it’s trying to reach?
It sends a broadcast onto the network.
What does de-encapsulation refer to?
Reverses the process of encapsulation
2 -> 3 -> 4 -> 5 -> 6 -> 7 -> app
What does encapsulation refer to?
The entire process of preparing data to go onto a network
app -> 7 -> 6 -> 5 -> 4 -> 3 -> 2 -> 1
What does OSI stand for?
Open Systems Interconnect
What does TCP/IP stand for?
Transmission Control Protocol over Internet Protocol
What does the FCS do?
Verifies that the data arrived correctly
What does the session software do?
Handles connecting applications to applications
What happens at the Presentation layer (Layer 6)?
Data from lower layers is translated into a format usable by the Application layer and vice versa.
What happens in the Logical Link Control (LLC) sublayer?
- Talking to the system’s OS
- Handling protocols
- Providing flow control
What happens in the Media Access Control (MAC) sublayer?
- Creates and addresses the frame
- Adds the NIC’s own MAC address and attaches MAC addresses to the frames.
- Adds or checks FCS
What is a benefit of using frames?
Frames keep any one NIC from hogging the wire
What is a NIC?
The Network Interface Card serves as the interface between the PC and the network.
What is a switch?
A switch is a device that filters traffic by MAC address to get data to the correct places.
What is an API?
An Application Programming Interface provides a standard way for programmers to enhance or extend applications’ capabilities.
What is CRC?
Cyclic Redundancy Check is what FCS uses to ensure data arrived correctly.
What is the last layer that deals with hardware?
Network Layer
What is the numbering namespace from which MAC address come from called?
Extended Unique Identifier (EUI)-48
What is the structure of a basic frame?
Receiving MAC -> Sending MAC -> type -> data -> Frame Check Sequence (FCS)
What is the structure of a packet?
Dest. IP -> Source IP -> Data
What is UTP?
Unshielded Twisted Pair is a type of cable usually containing 4 pairs of wires that can transmit and receive data
What are data chunks called at the Transport Layer?
Segments (for TCP)
or
Datagrams (for UDP)
What uniquely identifies every NIC?
Media Access Controller (MAC) address
What Windows utility do you use to find the MAC address for a system?
ipconfig /all
Where does a hub send data?
To all systems connected to the hub.
Which layer are cabling and the central box part of?
Physical (Layer 1)
Which layer of OSI defines the method of moving data between two computers?
Physical (Layer 1)
Which layer of the OSI seven-layer model keeps track of a system’s connections to send the right response to the right computer?
The Session Layer (Layer 5)
Which layer of the TCP/IP model controls the assembly and disassembly of data?
The Transport Layer
Which of the following is an example of a MAC address?
A) 0-255
B) 00-50-56-A3-04-0C
C) SBY3M7
D) 192.168.4.13
B) 00-50-56-A3-04-0C
Which part of a mac address is unique to each manufacturer?
The OUI
What decimal number corresponds to the binary number 11111111?
255
What type of device does a computer turn to first when attempting to make contact with a host on another network?
default gateway
Which statement describes SMTP?
SMTP is a connection based protocol
When your computer first joins an IVP6 network, what is the prefix of the IP address the computer first configures itself?
FE80::/10
You have just brought online a new secondary DNS server and notice your monitoring software report a significant increase in network traffic. Which two hosts on your network are likely to be causing the increased traffic and why?
The caching and primary DNS server because the caching server is requesting zone transfers from the primary server
Suppose you send data to 11111111 11111111 11111111 11111111 IP address on an IVP4 network. To which device are you transmitting?
All devices on your local network
If you are connected to a network that uses DHCP,and you need to terminate your windows workstation DHCP lease, which command would you use?
IP config/release
What computers are the highest authorities in the DOMAN Name System hieracrchy?
Root Server
What computers are the highest authorities in the DOMAN Name System hieracrchy?
Root Server
What veriosn of smb can be used across Windows, UNIX, and other operating systems?
CIFS
Suppose you want to change the default port for RDP as a security precaution. What port does RDP use by default, and from what range of numbers should you select a private port number?
3389 is default
Which type of DNS record identifies a mail server?
MX
How many bits does an IPv6 address contain?
128 bits
On what port is an IPv6 client listening for DHCP messages?
546 and 547
The second 64 of an autoconfigured IPV6 address may either be random or generated from the computer MAC address, which contains 48 bits. What standard defines the conversion of the MAC address to the IPv6 64-bit device id?
EUI-64
You issue a transmission from your workstation to the following socket on your LAN: 10.1.1.145:110. Assuming your network uses standard port designations, what Application layer protocol are you using?
POP
What protocol does a network gateway use to keep track of which internal client is talking to which external Web server
Split DNS design
You are the network manager for a computer training center that allows clients to bring their own laptops to class for learning and taking notes. Clients need access to the Internet, so you have configured your network’s DHCP server to issue IP addresses automatically. What DHCP option should you modify to make sure you are not wast- ing addresses that were used by clients who have left for the day?
Dynamic IP
What is the range of IP addresses that might be assigned by APIPA
169.254.0.1 through 169.254.255.254
While troubleshooting a network connection problem for a coworker, you discover the computer is querying a nonexistent DNS server. What command-line utility can you use to assign the correct DNS server IP address?
ipconfig /flushdns
FTP sometimes uses a random port for data transfer, but an FTP server always, unless programmed otherwise, listens to the same port for session requests from clients. What port is the FTP server listening on?
Port 21
What is the IPv4 loopback address? What is the IPv6 loopback address?
IPV4=127.0.0.1 IPV6= ::1
You have just set up a new wireless network in your house, and you want to determine whether your Linux laptop has connected to it and obtained a valid IP address. What command will give you the information you need?
ifconfig -a
You have decided to use SNAT and PAT on your small office network. At minimum, how many IP addresses must you obtain from your ISP for all five clients in your office to be able to access servers on the Internet?
1
If you know that your colleague’s TCP/IP host name is JSMITH, and you need to find out his IP address, what command should you type at your shell prompt or command prompt?
Nslookup jsmith
When determining whether a local network has any NetBIOS traffic, do you use the nslookup utility in interactive mode or a packet analyzer such as Wireshark?
Wireshark
List three signaling protocols discussed in the chapter that are used for communicating multimedia data.
H.323, MGCP, SIP
What version of the ping command do you use in Windows with IPv6 addresses? What version do you use on a Linux system
ping6—On Linux, ping -6—On Windows
When running a scan on your computer, you find that a session has been established with a host at the address 208.85.40.44:80. Which protocol is in use for this session? What command-line utility might you use to find out who the host is?
SIP and ping 208.85.40.44:80
What is OSI stands for
Open Systems Interconnection
How many layers does the OSI model has?
7
How do we call the process of sending the data from the bottom layer of the OSI model to the top layer?
Decapsulating
How do we call the process of sending the data from the top layer of the OSI model to the bottom layer?
Encapsulating
What does LLC stands for?
Logical Link Control (LLC)
To establish a connection, each device must send a Synchronization and receive an acknowledgement for it from the other device. Name the 3 steps involved in this process.
SYN
SYN-ACK
ACK
What does MUA stands for?
Mail User Agent
What are the functions of the LLC sub-layer of the Data Link Layer?
Flow control and Error control
What are the primary functions of the Presentation Layer?
Encryption, Formatting and Coding.
Network interface cards (NICs) work at which layer(s) of the OSI model?
Layer 1 and 2
List the Well-know ports of the following protocols and services: IMAP4, HTTPS, and Telnet
IMAP4 = 143 HTTPS = 443 Telnet = 23
Which of the following are transmission-signals that can be sent over the network at the Physical layer of the OSI Reference Model? Broadband, Light, Radio Waves, Baseband.
Light and Radio Waves
What type of connection is a UPD connection?
UDP is a connectionless protocol
The number of times a packet travels between routers to a destination across the network before it’s dropped is know as?
Time To Live ( TTL)
What’s the IEEE standard that describes features and functions of Ethernet technologies?
IEEE 802.3
What’s the IEEE standard that describes features and functions of Wireless technologies?
IEEE 802.11
What wireless broadband standards is known as IEEE 802.16
WIMAX officially called WirelessMAN
What type of connection is a TCP connection?
TCP is a Connection Oriented protocol
A method of identifying segments that belong to the same group of subdivided data is known as?
Sequencing
Witch of the following are Application Layer protocols?
SMTP, Telnet, NetBios, HTTP
SMTP, Telnet and HTTP
What is FCS stands for?
Frame Check Sequence.
The Frame Check Sequence is the numeric result of the CRC’s mathematical computation .
What is CRC stands for?
Cyclic Redundancy Check.
CRC is the method (algorithm) performed on the data for it’s verification. The result of a CRC computation is the FCS
What does Payload mean in a data segment or other transmission unit?
The essential data that is being carried within a packet or other transmission unit.
What does Overhead mean in a data segment or other transmission unit?
The data required to get the packet to its destination
Which layer of the OSI reference model contains the MAC and LLC sublayers? A) Network Layer B) Transport Layer C) Physical Layer D) Data Link Layer
D) Data Link layer
Which approach to bandwidth usage consumes all the available frequencies on a medium to transmit data? A) Broadband B) Baseband C) Time-division multiplexing D) Simplex
B) Baseband
Windowing is provided at what layer of the OSI reference model? A) Data link layer B) Network Layer C) Transport Layer D) Physical Layer
C) Transport Layer
IP addresses reside at which layer of the OSI reference model? A) Network layer B) Session layer C) Data link layer D) Transport layer
A) Network Layer
Identify the four layers of the TCP/IP stack:
a. Session layer
b. Transport layer
c. Internet layer
d. Data link layer
e. Network layer
f. Application layer
g. Network interface layer
B) Transport layer
C) Internet Layer
F) Application Layer
G) Network interface Layer
What is the range of well-known TCP and UDP ports? A) below 2048 B) Below 1024 C) 16,384-32,768 D) Above 8192
B) Below 1024
Which protocol supports a secure connection to a remote host via terminal emulation software? A) Telnet B) SSH C) FTP D) SFTP
B) SSH
Identify the well-known UDP port number for NTP. A) 53 B) 69 C) 123 D) 143
C) 123
Identify three e-mail protocols A) SNMP B) SMTP C) POP3 D) IMAP4
B)SMTP
C) POP3
D)IMAP4
What is Link
Term associated with IVIP6
describes the LAN bound router
AKA Local Link
What is tunneling
A method used by Ipv6 to transport packets over IPv4 networks
What is SNAT
Static Network Address Transportation
Allows the gateway to assign the same public IP address
What is a Subnet mask
A 32 bit number that helps one computer find another
What is a default gateway
Is the gateway device that nodes on the network turn to first for access.
What is a gateway
A computer router or other device that a host uses to access another network
IANA
Internet Assigned Numbers Authority
ICANN
Internet Cooperation for assigned names and numbers
What is FQDN
Fully qualified host name
Domain name
The last 2 parts of a host name
What is OUI
Organizationally Unique Identifier
IEEE
Institute of Electrical and Electronic Engineers
What is a DNS Server
Responsible for tracking computer names and their IP addresses
What is TDL
Top Level Domain
List some common TLD’s
ARPA, COM, EDU, GOV, ORG, NET, INT, MIL, BIZ, INFO, AERO, COOP
iana.ORG/DOMAINS/ROOT/DB
What is DNS
Domain Name System
What is DNS namespace
The entire collection of computer names and their associated IP addresses stored in databases on the DNS name server
What is a resolver
DNS client that requests information from the name server
What are root servers
A cluster of 13 servers
examples .com, .org, .edu
What is an Octet
A group of 4 decimal numbers of a 32 decimal set which make up an IP address
How many IPv4 classes are there
5
What are the 5 IPv4 classes
Class A,B,C,D,E
What is class A IPv4
1.xyz - 126.xyz
126 networks 16 million IP address
What is a class B IPv4
128.0.x.y -191.255.x.y 16,000 networks 65,000 ip addresses
What is a class B IPv4
192.0.0.x - 233.255.255.x
2 million networks
254 addresses
What is a socket
It is the hosts IP and Port Number
What is a NAT
Network Address Translation
a technique designed to conserve the # of public addresses
What is a PAT
Port address translation
The gateway uses PAT to assign a separate TCP port number to each session