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TCP IP Basics

Layer 3 - Transport Layer

  • Allows peer entities on source and destination hosts to carry on a conversation. It is just like end-to-end
  • TCP - Reliable, connection-oriented stream. It handles flow control and re transmission of lost packets.
  • IP - Connection-less, each packet is routed independently, does not guarantee delivery, each host has a unique IP address.

Ethernet Frame Format

PREAMBLE (7B) SFD (1B) DA(6B) SA(6B) LENGTH (2B) DATA(46-1500B) CRC (4B)
- Preamble and SFD for synchronisation on incoming data stream.

IPv4 Header Format

VER (4) HEADER LENGTH (4) TYPE OF SERVICE (8) TOTAL LENGTH (16)
IDENTIFICATION (16) FLAGS (3) FRAGMENT OFFSET (13)
TIME TO LIVE (8) PROTOCOL (8) HEADER CHECKSUM (16)
SOURCE IP (32)
DESTINATION (32)
OPTIONS AND PADDING

Options

  • Record Route
  • Source Routing
  • Padding - Header size should be multiple of 4

IPv6 Header Format

VERSION (4) TRAFFIC TABLE (8) FLOW LABEL (16)
Payload Length (16) Next Header (8) Hop Limit (8)
Source Address (128B)
Destination Address (128B)
Word IPv6 Field
Very Version
Tired Traffic Class
Frogs Flow Label
Play Payload Length
Near Next Header
High Hop Limit
Sea Source Address
Docks Destination Address