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Application Layer - Coggle Diagram
Application Layer
Providing IP Addressing Service
Domain Name Service
A human legible name is resolved to its numeric network device address by the DNS protocol
DNS Message Format
DNS server stores different types of resource records used to resolve names
Contain the name, address, and type of record
Unable to resolve the name using its stored records, contacts other servers
Server temporarily stores the numbered address that matches the name in cache memory
Windows ipconfig /displaydns displays all cached DNS
DNS Hierarchy
.jp - Japan
.org - non-profit organization
.au - Australia
Server Message Bloc
and finally user can access the resouces on the server as if the resources is local to the client host
Clients establish a long term connection to servers
Dynamic Host Configuration Protoco
Operation
Discover
Offer
Request
ACK
Function
DHCP allows a host to obtain an IP address DDHCP allows a host to obtain an IP address
Dynamic Host Configuration Protoco
File Transfer Protocol
To successfully transfer data, FTP requires two connections between the client and the server, one for commands and replies, the other for the actual file transfer
Clients establish a long term connection to servers
FTP allow data transfers between a client and a server
After the connection is established, the user can access the resources on the server as if the resource is local to the client host
Application Layer Protocols
The Application Layer provides the interface to the network
Presentation and Session Layers
Presentation layer has three primary functions:
Coding and conversion of application layer data
Compression of the data
Encryption of the data for transmission and the decryption of data upon receipt by the destination
Session Layer
Functions create and maintain dialogs between source and destination applications
Handles the exchange of information to initiate dialogs, keep them active, and to restart sessions
Application Layer Protocols
Domain Name Service Protocol (DNS)
Telnet
Bootstrap Protocol (BOOTP)
Dynamic Host Control Protocol (DHCP)
Hypertext Transfer Protocol (HTTP)
Post Office Protocol (POP)
Trivial File Transfer Protocol (TFTP) -
How Application Protocols Interact with End-User Applications
Peer-to-Peer Networks
Peer-to-Peer Applications
Common P2P Applications
eDonkey
eMule
Shareaza
BitTorrent
Bitcoin
LionShare
Client-Server Model
Application Layer Protocols and Services
Revisited
Hypertext Transfer Protocol (HTTP) : Browse the web
Post Office Protocol (POP) : used to enable users to receive email
Simple Mail Transfer Protocol (SMTP) : used to enable users to send email