EXPLAIN APPLICATION LAYER PROTOCOL
Application Layer (Asyraf)
The Application Layer is the seventh layer of the seven-layer OSI model. Application layer interface directly interacts with the application and provides common web application services. The application layer also makes a request to the presentation layer. Application layer is the highest level of open systems, providing services directly for the application process.
presentation and session layer(Asyraf)
to define the data format and encryption
presentation layer
defines how to start, control and end a session, including the control and management of multiple bidirectional messages
session layer
4.2.3 Explain how DNS and DHCP operate
DNS Hiearchy (Muhd Firdaus)
The nslookup Command(Anisa)
DNS Message Format (Muhd Firdaus)
Dynamic Host Configuration Protocol(Anisa)
Domain Name Service (Muhd Firdaus)
DHCP operation(Anisa)
Domain names convert the numeric address into a simple recognizable name
When a client makes a query, the server's DNS process first looks at its own records to resolve the name
A hiearchy of DNS servers contains the resource records that match names with addresses
The DNS protocol defines an automated service that matches resource names with the required numeric network address
If unable to resolve it, it contacts other servers to resolve the name
The server temporarily stores the numbered address in the event that the same name is requested again
The ipconfig/displaydns command displays all of the cached DNS entres on a Windows PC
a utility that allows a user to manually query the name servers to resolve a given host
The Dynamic Host Configuration Protocol (DHCP) for IPv4 automates the assignment of IPv4 addresses, subnet masks, gateways and other paramerts
distributed addresses are
leased for a set period of time,then returned to pool for reuse.
usually employed for end
user devices
DHCPv6 (DHCP for IPv6) provides
similar services for IPv6 clients.
TCP/IP application layer protocol(Asyraf)
HTTP
FTP
SMTP
DNS
BOOTP
DHCP
TFTP
POP
IMAP
HTTPS
CLIENT SERVER MODEL (ASYRAF)
Client and server processes are considered to be in the application layer.
Application layer protocols describe the format of the requests and responses between clients and servers.
Example of a client-server network is using an ISP’s email service to send, receive and store email.
PEER TO PEER NETWORK (ASYRAF)
Data is accessed from a peer device without the use of a dedicated server
Each device (known as a peer) can function as both a server and a client.
PEER TO PEER APPLICATION (ASYRAF)
A P2P application allows a device to act as both a client and a server within the same communication.
P2P applications require that each end device provide a user interface and run a background service.
COMMON P2P application
G2
BITCOIN
BitTorrent
eDonkey