Ip V 6 Mangement; Ipv6 Overview - 3Com 4210 PWR Configuration Manual

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IPv6 Overview

IPv6 Features
IP 6 M
V
n
The term "router" in this document refers to a router in a generic sense or an
■
Ethernet switch running a routing protocol.
3Com Switch 4210 Family supports IPv6 management features, but does not
■
support IPv6 forwarding and related features.
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.
Header format simplification
IPv6 cuts down some IPv4 header fields or move them to extension headers to
reduce the load of basic IPv6 headers. IPv6 uses a fixed-length header, thus
making IPv6 packet handling simple and improving the forwarding efficiency.
Although the IPv6 address size is four times that of IPv4 addresses, the size of basic
IPv6 headers is only twice that of IPv4 headers (excluding the Options field). For
the specific IPv6 header format, see Figure 189.
Figure 189 Comparison between IPv4 header format and IPv6 header format
0 7
Ver IHL TOS
Identification
TTL Protocol
Source address (32 bits)
Destination address (32 bits)
Options
Adequate address space
The source IPv6 address and the destination IPv6 address are both 128 bits (16
bytes) long.IPv6 can provide 3.4 x 10
requirements of hierarchical address division as well as allocation of public and
private addresses.
ANGEMENT
15
Total length
F Fragment offset
Header checksum
Padding
IPv4 header
38
C
ONFIGURATION
31 0 7 15
Traffic
Ver
class
Payload length
Source address
128 bits
Destination address
128 bits
IPv6 header
addresses to completely meet the
31
Flow label
Next
Hop limit
header