OSI Model and Internet protocols

Posted By on March 23, 2016


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LAN and WAN technologies
Protocols for Distributed systems

The Open Systems Interconnection model (OSI model) is a conceptual model that characterizes and standardizes the communication functions of a telecommunication or computing system without regard to their underlying internal structure and technology. Its goal is the inter-operability of diverse communication systems with standard protocols. The model partitions a communication system into abstraction layers. The original version of the model defined seven layers.

The model is a product of the Open Systems Interconnection project at the International Organization for Standardization (ISO).

OSI Layers and their functions

OSI Model
Layer Protocol data unit (PDU) Function
Host
layers
7. Application Data High-level APIs, including resource sharing, remote file access, directory servicesand virtual terminals
6. Presentation Translation of data between a networking service and an application; includingcharacter encoding, data compression and encryption/decryption
5. Session Managing communication sessions, i.e. continuous exchange of information in the form of multiple back-and-forth transmissions between two nodes
4. Transport Segment (TCP) /Datagram (UDP) Reliable transmission of data segments between points on a network, includingsegmentation, acknowledgement and multiplexing
Media
layers
3. Network Packet Structuring and managing a multi-node network, including addressing, routing andtraffic control
2. Data link Frame Reliable transmission of data frames between two nodes connected by a physical layer
1. Physical Bit Transmission and reception of raw bit streams over a physical medium

 

OSI Layers and respective protocols

OSI Model
Layer protocols
7. Application  FTP, HTTP, HTTPS, IMAP, IRC, DNS, AFP, MIME, POP3, SSH, RTP, SMTP, SOAP,
6. Presentation  TLS
5. Session RPC, SCP, NFS, PAP, SOCKS, NCP
4. Transport NBF, TCP, UDP, DCCP, SSL
3. Network AppleTalk, ICMP, IPsec, IPv4, IPv6
2. Data link IEEE 802.2, L2TP, LLDP, MAC, PPP
1. Physical DOCSIS, DSL, Ethernet physical layer, ISDN, USB
LAN and WAN technologies
Protocols for Distributed systems

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