Transmitting and Receiving in Communication Systems

Transmission Media

Wired and Wireless transmission media

Application level protocols

Application level is the level where user is controlling the information technology and creating the message for transmission

HTTP → Hypertext transfer protocol

Protocol that allows web browsers to communicate with web servers. Governs how information is transmitted between them
Enables caching (storing copies of files in a cahe (temporary storage location) so they can be accessed more quickly)

SMTP → Simple mail transfer protocol

standard protocol that is used to send and receive emails between people.Responsible for transmission of email messages from sender’s email client to recipient client
Includes error detection/correction mechanisms to ensure message delivered correctly.

SSL (Newer TLS) → Secure sockets layer (Transport layer security)

Protocol that creates an encrypted link and encrypts communication between client (I.e. Web browser) and server (I.e. Website)
Works using combination of public and private key encryption. Public key used to encrypt before sending. Private key used to decrypt data when received.
- Also uses digital certificates to ensure client is authentic, ad communication is not being intercepted

Communication control/addressing level protocols

Communication control/addressing level is the level where data is being prepared to be later sent in the transmission level

TCP → Transmission control protocol