Comptia Net + Chapter 1 Network Models Flashcards

Any hardware connections, like cables and connectors. turns binary into physical pulses (electrical or light). Essentially anything that moves data from one system to another

What does the OSI and TCP/IP model represent?

They represent how a network functions using discrete parts called layers.

The TCP/IP model only works on networks that use the

TCP/IP protocol suite.

What is layer one of the OSI model?

Physical Layer

What is layer 2 of the OSI model?

Data link

What is layer 3 of the OSI model?

network

What is layer 4 of the OSI model?

transport

What is layer 5 of the OSI model?

Session

What is layer 6 of the OSI model?

Presentation

What is layer 7 of the OSI model?

Application

What is a protocol?

A set of rules governing the exchange or transmission of data between devices.

What kind of network devices / things are used in the physical layer?

Copper cabling, fiber optics, radio waves, hubs.

What does every NIC come with?

A Media Access Control Address

True or false: NICs cannot have the same MAC address.

True

All NIC Manufacturers must contact the ____ and request a block of MAC addresses

IEEE (Institute of Electronics and Electrical Engineer)

Hex is a base __ numbering system

16

In a base 16 numbering system, the numbers range from

0-15

The first 10 numbers in a base 16 numbering system are

0-9

After the first 10 numbers in a base 16 numbering system, the numbers change to letters ranging from

A-F

The first 6 digits in a MAC address are referred to as the

Organizational Unique Identifier or the OUI

What is the MAC-48?

The method the IEEE use to form MAC addresses

The first 24 bits in the MAC-48 represent the

OUI - Organizational Unique Identifier

What is a Frame?

A container for a chunk of data moving across a network

What does a frame do?

Encapsulates-puts a wrapper around- information and data for easier transmission

What does the NIC do with Frames?

Creates, sends, receives, reads and destroys Frames.

What part of the OSI model creates frames?

Layer 2

All NICs on the same network must use the same_____?

frame type

What happens when a NIC doesn't use the same frame type as other NIC's on the network?

It cannot communicate with the other devices.

Name the sections of a generic Frame.

Recipients MAC address, Senders MAC address, Type, Data, FCS

What is the FCS portion of a Frame?

Frame Check Sequence

How does the FCS portion of a frame work?

It uses a binary math called Cyclic Redundancy Check (CRC) to ensure all data arrives.

What is the typical data limit of a Frame?

1500 bytes

What happens when the data sent is too big for the frame?

The sending software must chop up the data into frame-size chunks. The chunks must then be reassembled once they are received.

What is the MAC broadcast Address?

FF-FF-FF-FF-FF-FF

If the NIC doesn't know the receiving devices MAC address how does it get it?

The NIC sends a frame using the broadcast address.

A frame sent using the broadcast address will cause all NIC's on the same network to

Receive it

What is in the broadcast frames' data?

A request for the receiving systems MAC address.

The system with the target MAC address will read the ____ in the broadcast packet

request

After the receiving system reads the request in the broadcast packet, it will respond with what?

Its MAC address

When a central box or hub receives a frame, what does it do?

copies the frame and sends it to every other system on the network

If the destination address of the frame is the same as the NIC that received it what will it do?

Process the frame

If the destination address of the frame is different then the NIC that received the frame, what will it do?

it will delete the frame.

What does the NIC use to make sure the data from the frame is valid?

The FCS, Frame check Sequence

If the FCS of the frames data is valid, what does the NIC do?

strips off all the frame information and sends the data to the OS

Any device that deals with the MAC address is part of what layer?

Layer 2- The Data link layer

What are the two main aspects or function of the NIC?

LLC - Logical Link ControlMAC - Media Access control

What does the LLC do?

Logical Link Control - the aspect of the NIC that talks to the systems operating system. Handles multiple network protocols and provides flow control

The Data Link Layer is the only layer with what?

Sub-Layers

What is the Job of the MAC portion of the NIC?

- creates and addresses frames.- adds and checks the FCS.

What devices would you expect to be in OSI layer 2?

Switch's and NIC's

The NIC is often considered to be a part of which two OSI Layers?

The physical and the data layers

If the FCS check fails, how does Ethernet determine precisely which bit is damaged?

The FCS provides error detection only. Error recovery must be performed through separate means, Ethernet will drop the frame and if TCP protocol is utilized it will notice the drop frame and request re-transmission of the data

MAC addresses are referred to as what kind of addresses?

Physical Addresses

The MAC sends the frames along what?

Network cabling

IP addressing is considered what type of addressing?

Logical Addressing

The Internet Protocol is the primary logical addressing protocol for what?

TCP/IP

What does IP do?

makes sure that a piece of data gets where it needs to go on the network. IE Routes packets through various networks

IP addresses are referred to as what?

logical addresses

How does the Internet Protocol route packets through the network?

By giving devices on the network unique network ID's or network IP's.

IP addresses use a _ _ numbering system.

dotted octet

IP addresses utilize 4 ____ Bit numbers.

8

What is the number range for each 8 bit number on an IP address.

0-255

True or False: Two machines on the same network can have the same IP address.

False.

What are the two main functions of a router?

1. use IP addresses to forward data2. Connect subnets

In a TCP/IP network, what are the two identifiers that each network device has?

1. Mac Address2. IP address

Where is the IP address stored?

On the system software

For data in a TCP/IP network to be sent successfully, it must be wrapped in two distinct containers. What are they?

- A frame of some Type- An IP specific container so routers know where to send the data, regardless of physical type.

in a TCP/IP network, an IP-specific container is known as what?

Packet

What happens when a packet gets sent to a NIC?

The NIC encloses the packet with in a frame

In a TCP/IP network, when data is sent from one computer to another, the data can go through many ____ before it reaches its destination.

Routers

When a router receives an incoming frame, what does it do?

1. Strips the off the incoming frame,2. Determines where its going based on the IP address3. Creates a new frame4. Sends the packet on its way.

When a router creates a new frame for a packet, it changes that frame to be _____ for the next router.

The same type needed

When the Frame/packet reaches the destination subnet's router, what does it do?

1. Strip off the incoming frame2. Look at the destination IP address3. Add a frame with the appropriate destination MAC address that matches the destination IP address

What is a segmentation?

The breaking up of data into chunks to fit into frames to be sent.

What is a segment

A chunk of data

What OSI layer deals with Segments?

Layer 4 - Transport Layer

Segments get a special number called a _________, to help them get reassembled on the other side.

Sequence

(True or False) Datagrams are simpler versions of segments that don't need a sequence number?

True

Embedded into the data of a packet is a _____ number.

Sequence

What do sequence numbers tell the system?

1. The total number of segments2. How to put them back together

What is the purpose of the Transport layer in the OSI model?

1. Assemble/Disassemble data2. initiate requests for packets that weren't received in good order

What does the Session Layer of the OSI handle?

connection applications to other applications

What does the Sessions layer of the OSI do with sessions?

- initiates, accepts, opens and closes existing sessions.

What is the command prompt to see active sessions?

netstat -a

What does the Presentation layer of the OSI model do?

Translates data from the lower layers into a format usable by the application layer and vice versa

What does the application layer do?

It is the layer which interacts with the user to provide access to services and data that is sent/received over a network.

What does the application layer refer to in the OSI model?

It refers to the code built into all operating systems that enables network-aware applications.

What is API?

Application Programming Interfaces

What is the purpose of the Application Programming Interface (API)?

its used by programmers to enhance or extend and applications capabilities

What is encapsulation in terms of networking?

The process of preparing data to go onto a network. This includes all the steps of the OSI model

What is De-encapsulation in terms of networking?

When a receiving computer reverses the encapsulation process, stripping all the extra header information out as the

What is more commonly used today as a network model: TCP/IP or OSI?

TCP/IP

How many layers does the TCP/IP Model consist of?

Four

What are the Layers of the TCP/IP Model?

1. Network interface or Link Layer2.Internet Layer3. Transport Layer4. Application Layer

The link layer of the TCP/IP model represents what in-comparison to the TCP/IP Model?

Layer 1 (Physical) and Layer 2 (Data link)

The Link layer of the TCP/IP model deals with what?

Any part of the network that deals with complete frames.

In the TCP/IP model, when the frame is stripped off a IP packet, where does it go?

The internet layer

What does the internet layer of the TCP/IP model deal with?

Any device or protocal that deals with pure IP Packets Routers, ip addressing.

What layer of the TCP/IP model deals with creating IP packet?

The internet layer.

The Transport Layer of the TCP/IP model combines what features of the OSI Model?

Transport and session layer with some of the application layer.

The TCP/IP model defines what two types of communication functions?

1. Connection-Oriented2. Connectionless

What is TCP?

This is Transmission Control Protocol; Connection oriented protocol.

What are 3 important characteristics of TCP?

1. Reliable transport of segments; If segment is dropped, protocol detects it and re-sends segment2. Acknowledgements received for successful communications3. Used for all network data that needs to be assured to get to its destination

What does UDP stand for?

This stands for User Datagram Protocol

What are some characteristics of UDP?

These are characteristics of this protocol:- Connection-less Protocol-Unreliable transport of segments: If dropped, sender is unaware-No Re-transmission-Good for audio/video streaming-No sequencing-Lower overhead for increased performance