Basic IPv6 Course

The IPv6 header

• 1. Basic IPv6 header

• 2. IPv6 extension headers

• Changes to the basic header:

• From 12 fields in IPv4 to 8 fields in IPv6 (REDUCTION IN THE

NUMBER OF FIELDS)

• IPv4 “Options” field (variable) eliminated => fixed size

• IHL (header length) eliminated, fixed header size

• Checksum IPv4 eliminated: redundant layer 2, 4 and application

layer

• IPv4 fragmentation fields eliminated (Identification, Flags,

Fragment Offset) -> Will use header extensions

Advantages of the new basic header:

• Less complex, fixed size, aligned to 64 bits -> processed

faster by routers --> Scalable

• Redundant, unnecessary features are eliminated:

checksum, header length (IHL)

• New field for QoS: Flow Label

IPv6 extension headers (II)