IPv6 Header Improvements

Overview

This lecture outlines the key improvements in the IPv6 header structure, detailing each field and its function compared to IPv4.

IPv6 header is simpler and shorter than the IPv4 header to improve network performance.
Optional fields are removed from the main header and handled using extension headers.

The version field is 4 bits and specifies the IP version in use.
The traffic class field is 8 bits and assigns a priority to specific types of traffic.
The flow label field is 20 bits and works with the traffic class to help routers manage quality of service.
The payload length field is 16 bits and indicates the size of the data payload.
The next header field specifies what type of header or protocol follows the current header.
The hop limit field is 8 bits, serving the same role as the TTL (time-to-live) field in IPv4.
The source and destination address fields are each 128 bits, accommodating IPv6’s larger address size.

Extension headers are optional and follow the main IPv6 header as specified by the next header field.
Extension headers each have their own next header field, enabling a chain of headers for optional configuration.
Moving optional fields out of the base header reduces its size and improves data transmission efficiency.

IPv6 header — The main data structure at the start of an IPv6 packet, containing essential routing information.
Version field — Specifies the version of the IP protocol (4 bits).
Traffic class field — Sets traffic priority for quality of service (8 bits).
Flow label field — Helps manage quality of service for specific data flows (20 bits).
Payload length field — Indicates the length of the data part of the packet (16 bits).
Next header field — Identifies what follows the header (another header or payload).
Hop limit field — Limits packet lifespan, prevents loops (8 bits).
Source/Destination address fields — Contain 128-bit addresses of sender and recipient.