Encapsulation of Layers in the OSI Model, TCP/IP Protocol Suite скачать в хорошем качестве

Encapsulation of Layers in the OSI Model, TCP/IP Protocol Suite

DAY 12 – ENCAPSULATION IN OSI MODEL AND TCP/IP PROTOCOL SUITE- 1) ENCAPSULATION IN OSI MODEL – DEFINITION Encapsulation is the process of adding headers (and sometimes trailers) to data as it moves down the OSI layers at the sender side. Each layer adds its own control information. At the receiver side, the reverse process is called Decapsulation. -------------------------------------------------- 2) DATA FLOW IN OSI MODEL (SENDER SIDE) Application Layer: User creates data (Message) Presentation Layer: Formats, encrypts, compresses data Session Layer: Adds session information Transport Layer: Adds Transport Header Segment is formed Header contains: Source Port Destination Port Sequence Number Network Layer: Adds IP Header Packet is formed Header contains: Source IP Destination IP Data Link Layer: Adds Frame Header and Trailer Frame is formed Header contains: Source MAC Destination MAC Trailer contains: Error detection (CRC) Physical Layer: Converts frame into bits and transmits -------------------------------------------------- 3) ENCAPSULATION SUMMARY TABLE Layer Data Unit Name --------------------------------- Application Data Transport Segment Network Packet Data Link Frame Physical Bits -------------------------------------------------- 4) DECAPSULATION (RECEIVER SIDE) Physical → Data Link → Network → Transport → Session → Presentation → Application Each layer removes its corresponding header and passes remaining data upward. -------------------------------------------------- 5) TCP/IP PROTOCOL SUITE – DEFINITION TCP/IP (Transmission Control Protocol / Internet Protocol) is a practical networking model used in the Internet. It consists of four layers. -------------------------------------------------- 6) TCP/IP MODEL LAYERS Application Layer Combines OSI Application, Presentation, Session Examples: HTTP, HTTPS, FTP, SMTP, DNS Transport Layer Provides end-to-end communication Protocols: TCP – Reliable UDP – Unreliable Internet Layer Handles logical addressing and routing Protocol: IP (IPv4, IPv6) Network Access Layer Handles physical transmission and MAC addressing Examples: Ethernet, ARP -------------------------------------------------- 7) COMPARISON: OSI VS TCP/IP OSI Model: 7 layers Conceptual model Developed by ISO TCP/IP Model: 4 layers Practical model Used in Internet Layer Mapping: OSI Layer TCP/IP Layer ------------------------------------------ Application Application Presentation Application Session Application Transport Transport Network Internet Data Link Network Access Physical Network Access -------------------------------------------------- 8) KEY DIFFERENCE BETWEEN TCP AND UDP TCP: Reliable Connection-oriented Error checking Slower UDP: Unreliable Connectionless Faster No guaranteed delivery