Ipv6 Basics Configuration; Ipv6 Overview; Ipv6 Features - HP A5120 EI Series Configuration Manual

IPv6 basics configuration

IPv6 overview

Internet Protocol Version 6 (IPv6), also called IP next generation (IPng), was designed by the Internet
Engineering Task Force (IETF) as the successor to Internet Protocol version 4 (IPv4). The significant
difference between IPv6 and IPv4 is that IPv6 increases the IP address size from 32 bits to 128 bits.

IPv6 features

Header format simplification
IPv6 removes several IPv4 header fields or moves them to the IPv6 extension headers to reduce the length
of the basic IPv6 packet header. The basic IPv6 packet header has a fixed length of 40 bytes to simplify
IPv6 packet handling and to improve forwarding efficiency. Although IPv6 address size is four times of
IPv4 address size, the basic IPv6 packet header size is only twice the size of the option-less IPv4 packet
header.
Figure 51 IPv4 packet header format and basic IPv6 packet header format
0 3 7
Ver IHL
Identification
TTL Protocol
Source Address (32 bits)
Destination Address (32 bits)
Larger address space
The source and destination IPv6 addresses are 128 bits (or 16 bytes) long. IPv6 can provide 3.4 x 10
addresses to meet the requirements of hierarchical address division and the allocation of public and
private addresses.
Hierarchical address structure
IPv6 uses hierarchical address structure to make route searches faster and reduce the IPv6 routing table
size by route aggregation.
Address autoconfiguration
To simplify host configuration, IPv6 supports stateful and stateless address autoconfiguration.
15 23
ToS Total Length
F Fragment Offset
Header Checksum
Options Padding
IPv4 header
31 0 3 11 15
Traffic
Ver
Class
Payload Length
Source Address (128 bits)
Destination Address (128 bits)
Basic IPv6 header
112
23 31
Flow Label
Next
Hop Limit
Header
38