Communicating over the network The structure of a network, including devices and media necessary for communications The functions protocols perform in network communications The advantages of using a layered model to describe network functionality The role of each layer in the OSI network model and the TCP/IP network model The importance of addressing and naming schemes in network communications
The destination device
An end device
An intermediate device
A media device
Network A -- WAN
Network B -- WAN
Network C -- LAN
Network B -- MAN
Network C -- WAN
Network A -- LAN
Piping
PDU
Streaming
Multiplexing
Encapsulation
Source
End
Transfer
Intermediary
WAN
MAN
LAN
WLAN
A, C, D
B, E, G, H
C, D, G, H, I, J
D, E, F, H, I, J
E, F, H, I, J
Determine pathways for data
Initiate data communications
Retime and retransmit data signals
Originate the flow of data
Manage data flows
Final termination point for data flow
Define the structure of layer specific PDU's
Dictate how to accomplish layer functions
Outline the functions necessary for communications between layers
Limit the need for hardware compatibility
Require layer dependent encapsulations
Eliminate standardization among vendors
Tracks delay between end devices
Enables consistent network paths for communication
Allows modification of the original data before transmission
Identifies pieces of data as part of the same communication
Ensures that data pieces can be directed to the correct receiving end device
Supports error detection
Ensures ordered arrival of data
Provides delivery to correct destination
Identifies the devices on the local network
Assists intermediary devices with processing and path selection
Network
Transport
Physical
Data Link
Session
Corruption of a frame during transmission
Data reassembled at the destination
Retransmitted packets due to lost communication
A layer specific encapsulation
Manage data flows
Originate data flow
Retime and retransmit data signals
Determine pathways for data
A LAN is usually in a single geographical area
The network is administered by a single organization
The connection between segments in the LAN is usually through a leased connection
The security and access control of the network are controlled by a service provider
A LAN provides network services and access to applications for users within a common organization
Each end of the network is generally connected to a Telecommunication Service Provider (TSP)
To identify devices on the local media
To identify the hops between source and destination
To identify to the intermediary devices the best path through the network
To identify the source and destination end devices that are communicating
To identify the processes or services that are communicating within the end devices
File server
IP phone
Laptop
Printer
Switch
Physical
Data Link
Network
Transport
The destination device on the local media
The destination host address
The bits that will be transferred over the media
The source application or process creating the data
No address is added
The logical address is added
The physical address is added
The process port number is added
Path determination and packet switching
Data presentation
Reliability, flow control, and error detection
Network media control
The division of segments into packets
Physical, network, application, data link, presentation, session, transport
Application, physical, session, transport, network, data link, presentation
Application, presentation, physical, session, data link, transport, network
Application, presentation, session, transport, network, data link, physical
Presentation, data link, session, transport, network, physical, application
1
2
3
4
Logical
Physical
MAC
IP
Port
The client decapsulates the segment and opens the web page
The client adds the appropriate physical address to the segments so that the server can forward the data
The server converts the data to bits for transport across the medium
The server adds the source and destination address to each segment header to deliver the packets to the destination
The server adds the source and destination physical addresses to the packet header