Terms in this set (7)
Layer in which communication between application occurs and where there are a number of communication protocols such as:
FTP - File transfer protocol
DNS - Domain Name System
SMTP - Simple Mail Transfer Protocol
Its major network device or component is the gateway.
It consists of protocols that focus on process-to-process communication across an IP network and provides a firm communication interface and end-user services.
Layer in which the format of data is translated or converted to be compatible with the system.
Translates data, encrypts it, compresses it, and converts it across the network.
Changes ASCII to Extended Binary.
The session layer manages sessions or dialog between computers. It starts them, and ends them
Performs check-pointing and recovery of sessions. Uses remote procedure protocols (RPC's).
Sessions are most commonly implemented on Web browsers using protocols such as the:
Zone Information Protocol
Session Control Protocol
The session layer supports full-duplex and half-duplex operations and creates procedures for checkpointing, adjournment, restart and termination.
The transport layer is also responsible for the management of error correction, providing quality and reliability to the end user. This layer enables the host to send and receive error corrected data, packets or messages over a network and is the network component that allows multiplexing.
The Transport layer provides services such as:
Multiplexing - multiplexing allows the use of simultaneous applications over a network such as when different internet browsers are opened on the same computer.
Byte orientation: Some applications prefer to receive byte streams instead of packets; the transport layer allows for the transmission of byte-oriented data streams if required
Traffic control - The transport layer can identify the symptoms of overloaded nodes and reduced flow rates.
Flow Control - Devices at each end of a network connection often have no way of knowing each other's capabilities in terms of data throughput and can therefore send data faster than the receiving device is able to buffer or process it.
Same Order Delivery: Ensures that packets are always delivered in strict sequence
Data Integrity: Using checksums, the data integrity across all the delivery layers can be ensured
Connection-Oriented Communication: Devices at the end-points of a network communication establish a handshake protocol to ensure a connection is robust before data is exchanged.
model responsible for end-to-end communication over a network. It provides logical communication between application processes running on different hosts within a layered architecture of protocols and other network components.
The layer that provides data routing paths for network communication. Data is transferred in the form of packets via logical network paths in an ordered format controlled by the network layer.
Logical connection setup, data forwarding, routing and delivery error reporting are the network layer's primary responsibilities.
It selects and manages the best logical path for data transfer between nodes
Internet Protocol and Netware IPX/SPX are the most common protocols associated with the network layer.
In the OSI model, the network layer responds to requests from the layer above it (transport layer) and issues requests to the layer below it (data link layer).
Network layer protocols exist in every host or router. The router examines the header fields of all the IP packets that pass through it.
Data Link layer
The data link layer is used for the encoding, decoding and logical organization of data bits. Data packets are framed and addressed by this layer, which has two sublayers.
The data link layer's first sublayer is the media access control (MAC) layer. It is used for source and destination addresses. The MAC layer allows the data link layer to provide the best data transmission vehicle and manage data flow control.
The data link layer's second sublayer is the logical link control. It manages error checking and data flow over a network.
The physical layer deals with bit-level transmission between different devices and supports electrical or mechanical interfaces connecting to the physical medium for synchronized communication.
This layer plays with most of the network's physical connections - wireless transmission, cabling, cabling standards and types, connectors and types, network interface cards, and more - as per network requirements. However, the physical layer does not deal with the actual physical medium (like copper, fiber).
The physical layer is aimed at consolidating the hardware requirements of a network to enable the successful transmission of data.