Network Models Flashcards
Explain functions and application of various network devices.
Layer 1
Physical
Layer 2
Data Link
Layer 3
Network
Layer 4
Transport
Layer 5
Session
Layer 6
Presentation
Layer 7
Apllication
Unshielded Twisted Pair(UTP)
Cable for telephone and network composed of pairs of wires twisted around each other at specific interval. Twist reduce interference. More twist less interference
Physical Layer
Anything that moves data from one system to another
Defines hardware connections and turns binary into physical pulses.
What operates at the Physical Layer?
Repeaters, hubs, cabling, fiber optics, and radio waves
NIC
Allows a PC to link physically to a network
MAC Address
Unique 48-bit address assigned to NIC’s
Organizationally Unique Identifier (OUI)
First 24 bits of a MAC address, assigned to the NIC manufacturer by the IEEE
What are the last 6 digits of a MAC address?
Device ID
Physical Address
Address burned into a ROM chip on a NIC
Example of Physical Address
MAC
A defined series of binary data that is the basic container for a discrete amount of data moving across a network
Frame
A sequence of bits placed in a frame that is used to check the primary data for errors
Frame Check Sequence (FCS)
A mathematical method used to check for errors in long streams of transmitted data with high accuracy
Cyclic Redundancy Check (CRC)
An electronic device that sits at the center of a star topology network, providing a common point for connection of network devices.
Hub
The address a NIC attaches to a frame when it wants every other NIC on the network to read it
Broadcast Address
255.255.255.255
General Broadcast Address
FF-FF-FF-FF-FF-FF
Broadcast MAC Address
Data Link Layer
Any device that deals with a MAC Address
What filters and forward frames based on MAC address and operates on the Data Link Laye?
Bridges
A device that connects two networks and passes traffic between them based only on the node address, so that traffic between nodes on one network does not appear on the other network. Ex. Ethernet bridge only looks a the MAC address.
Bridge
What are the two aspects of NIC’s
Logical Link Control (LLC) and Media Access Control (MAC)
The aspect of the NIC that talks to the OS, places outbound data coming “down” from the upper layers of software into frames and create the FCS on each frame
Logical Link Control (LLC)
Which layer on the OSI model has sublayers?
Data Link
The process of assigning organized blocks of logically associated network addresses to create smaller manageable networks called subnets
Logical Addressing
Example of logically addressing
IP Addresses
Subnet
Each independent network in a TCP/IP internetwork
Special software that exists in every network-capable OS that acts to create unique identifiers for each system. It also creates a set of communication rules for issues like how to handle data chipped up into multiple packets and how to deal with routers.
Network Protocol
A set of protocols that are commonly used together and operate at different levels of the OSI seven layer model
Protocol Suite
Basic component of communication over a network. A group of bits of fixed maximum size and well-defined format that is switched and transmitted as a complete whole through a network. It contains source and destination address, data, and control information
Packet
A device that connects separate networks and forwards a packet from one network to another based only on the network address for the protocol being used.
Router
What operates on Layer 3?
Routers
Which layer is the last to deal directly with hardware?
Network Layer (Layer 3)
Assembly/disassembly and also initializes requests for packets that weren’t received in good order
Transport Layer (Layer 4)
TCP, UDP, SPX, and NetBEUI operates at which Layer?
Transport Layer
The Transport Layer break data down into which kind of chucks?
Segments or Datagrams
Manages connections between machines (initiates sessions, accepts incoming sessions, and open and close existing sessions
Session Layer (Layer 5)
NetBIOS and Sockets operate at which layer
Session Layer
Handles the process of differentiating among various types of connections on a PC (connecting applications to applications)
Session Software
Which two encryptions protocols used in ecommerce are initiated at Layer 5
TLS and SSL
TLS and SSL are encrypted and decrypted at which Layer
Layer 6
Which layer manages data encryption, hides the difference among various types of computer systems (Data conversion)
Presentation Layer (Layer 6)
Provides tools for programs to use to access the network
Application Layer (Layer 7)
HTTP, FTP, SMTP, and POP3 are all examples of protocols that operate at which layer?
Application Layer
Shared functions, subroutines, and libraries that allow programs on a machine to communicate with the OS and other programs
Application Programming Interface (API)
The process of stripping all the extra header information from a packet as the data moves up a protocol stack
De-encapsulation
The process of putting the packets from one protocol inside the packets of another protocol. Ex. Application to Data Link layers. Each layer adds more information so that the data get to the correct recipient and the recipient knows what to do with the data.
Encapsulation
Where dos a hub send data?
To all the systems connected to the hub
What uniquely identifies every NIC?
Media access control address (MAC Address)
What Windows utility do you use to find the MAC address for a system?
ipconfig /all
A MAC address is known as a(n) ____ address
Physical
A NIC sends data is secrete chunks called _____
Frames – Network use frames to keep any one NIC from hogging the wire
Which MAC address begins a frame?
Receiving system – followed by the MAC address of the sending NIC – followed, in turn, by type of encapsulated data, the data, and FCS
A frame ends with a special bit called the frame check sequence (FCS). What does the FCS do?
Verifies that the data arrived correct
00-50-56-A3-04-0C is an example of
MAC address
Which layer of the TCP/IP model controls the assembly and disassembly of data?
Transport Layer
Which layer of the OSI seven-layer model keeps track of a system’s connections to send the right response to the right computer?
Session
Name TCP/IP four layers
Application, Transport, Internet, Link/Network Interface
Makes up the OSI model’s Layer 1 and 2
Link Layer
Any device or protocol that deals with pure IP packets –getting an OP packet–getting an IP packet to its destination
Internet Layer
Which layer is compared to OSI Layers 4,5, and part 7
Transport Layer
Which layer is compared to OSI Layer 5-7
Application Layer