Host-to-Host Communications Flashcards
Defines electrical, mechanical, procedural, and functional specifications for activating, maintaining, and deactivating the physical link between devices. This layer deals with electromagnetic representation of bits of data and their transmission.
Layer 1: The physical layer
Defines how data is formatted for transmission and how access to physical media is controlled. This layer typically includes error detection and correction to ensure reliable data delivery. The data link layer involves network interface controller to network interface controller (NIC-to-NIC) communication within the same network. This layer uses a physical address to identify hosts on the local network.
Layer 2: The data link layer
Provides connectivity and path selection beyond the local segment, all the way from the source to the final destination. The network layer uses logical addressing to manage connectivity. In networking, the logical address is used to identify the sender and the recipient.
Layer 3: The network layer
Defines segmenting and reassembling of data belonging to multiple individual communications, defines the flow control, and defines the mechanisms for reliable transport, if required.
Layer 4: The transport layer
Establishes, manages, and terminates sessions between two communicating hosts, to allow them to exchange data over a prolonged time period. The session layer is mainly concerned with issues that application processes may encounter and not with lower layer connectivity issues. The sessions, also called dialog.
Layer 5: The session layer
ensures that data sent by the application layer of one System is “readable” by the application layer of another system. It achieves that by translating data into a standard format before transmission and converting that format into a format known to the receiving application layer.
Layer 6: The presentation layer
Is the OSI layer that is closest to the user. It provides services to user applications that want to use the network. Services include e-mail, file transfer, and terminal emulation. An example of a user application is the web browser.
Layer 7: The application layer
This layer is also known as the media access layer. It defines protocols used to interface the directly connected network. Tasks of the protocols at this layer are closely related to the characteristics of the physical medium and deal primarily with physical network details. The link layer is also referred to as a network interface, network access, or even data link layer. An example of the TCP/IP link layer protocol is Ethernet.
Link layer
This layer routes data from the source to the destination, provides a means to obtain information on how to reach other networks, and deals with reporting of errors. The Internet layer provides logical addressing. Logical addressing ensures that a host is uniquely identified. P protocols, namely IP version 4 (IPv4), and the newer version IP version 6 (IPv6), reside in this layer.
Internet layer
Along with the Internet layer, this layer is the core of the TCP/IP architecture. It is placed between so called “data mover” protocols of the Link and Internet layers and software-oriented protocols of the Application layer. There are two main protocols at this layer, TCP and User Datagram Protocol (UDP).
Transport layer
The functions of this layer mainly deal with user Interaction. It supports user applications by providing protocols and services that let you actually use the network. It also supports network application programming interfaces (APIs), that allow programs to access the network services, regardless of the operating system that they are running on. This layer accommodates protocols such as Hypertext Transfer Protocol (HTTP), Secure HTTP (HTTPS), Domain Name System (DNS), File Transfer Protocol (FTP), Simple Mail Transfer Protocol (SMTP), Secure Shell (SSH), and many more.
Application layer
The general term for the PDU that is used at the Application layer
Data
A Transport layer PDU
Segment
An Internet layer PDU
Packet
A Link layer PDU
Frame
