Question

Select one of the objectives below, do some additional research on the topic. Then write a two or three paragraph post expanding on the topic.

Objectives:

• the services provided by the application layer

• the Hypertext Transfer Protocol (HTTP), used to retrieve web pages

• the Simple Mail Transfer Protocol (SMTP), used to exchange e-mails

• the File Transfer Protocol (FTP), used for transferring large amounts of data

• Instant Messaging and presence services

Answer 1

I have explained about the first topic. Please leave a comment if you have any doubt.

The services provided by the application layer:

Application layer is the 7^th layer of the TCP/IP protocol. It’s the only layer that directly communicates with the end user. It defines standard Internet services and network applications and provides an interface between the applications and network. Important services provided by this layer are:

1. Network Virtual terminals: It allows a host terminals on a multi-user network to interact with other hosts. That helps users from far away (by remote login) to access information from another host. For remote host it’s like communicating to local machine and allows user to log on like Telnet
2. Mail Services: The layer is used for exchanging messages between users. It includes exchanging emails between users. Message handling system is a protocol that helps in transferring mail over the internet.
3. Directory Service: In case of Directory Service a directory is a source of information about any item which could be a file or Organization or anything. These objects are managed by directory services. So, users can access information stored at a centralized place. It allows users to locate and access these resources and also but also let them manage the relationships among them. For example LDAP is a directory Service.
4. File Services: Users can access files in a remote computer and manage it. They can also retrieve files from a remote computer. FTP is a good example.