IPv6 support

Last Updated : Apr 13, 2023 |

Internet Protocol version 6 (IPv6) is a successor to IPv4. IPv6 supports 128-bit addressing, allowing a larger number of IP addresses. IPv6 also enhances security, simplicity of configuration, and routing performance. IPv6 can coexist with IPv4 networks, facilitating the transition process.

The Internet Engineering Task Force (IETF) published RFC 2460 defines IPv6.

Note:

Some Branch Gateway features are not supported in IPv6.

Addressing

IPv6 provides about 3.4x1038 unique IP addresses. This eliminates the IPv4 mechanisms, such as Network Address Transitions (NAT), that are used to relieve IP address exhaustion. IPv6 addresses are normally written as hexadecimal digits with colon separators. For example: 2005:af0c:168d::752e:375:4020. The double colon “::” represents a string of zeroes, according to RFC4291.

Routing

IPv6 simplifies the routing process in the following ways:

  • Simplified packet header, despite enhanced functionality.

  • IPv6 routers do not perform fragmentation. This is carried out by IPv6 hosts.

  • IPv6 routers do not need to recompute a checksum when header fields change.

  • Routers do not need to calculate the time a packet spent in the queue.

  • IPv6 supports stateless address configuration. IPv6 hosts can be configured automatically when connected to a routed IPv6 network through ICMPv6. Stateful configuration using DHCPv6 and static configuration are also available.

Deployment and transition

There are several mechanisms that simplify the deployment of IPv6 running alongside IPv4. The key to the IPv6 transition is dual-stack hosts. Dual-stack hosts refer to the presence of two IP software implementations in one operating system, one for IPv4 and one for IPv6. These dual-stack hosts can run the protocols independently or as hybrids. Hybrid dual-stack hosts are common on recent server operating systems and computers.

Tunelling allows to use IPv4 infrastructure to carry IPv6 packets when an IPv6 host or network must use the existing IPv4 infrastructure. Tunneling can be either automatic or configured. Configured tunneling is more suitable for large, well-administered networks.

Key differences between IPv4 and IPv6

Features

IPv4

IPv6

Address space

32-bit, about 4.3x109

128-bit, about 3.4x1038

Configuration

Requires DHCP or manual configuration.

Stateless auto-configuration. Does not require DHCP or manual configuration.

Address format

Decimal digits with colon separators, for example: 192.168.1.1

Hexadecimal digits with colon separators. For example: 2005:af0c:168d::752e:375:4020. The double colon “::” represents four zeros “0000”.

Broadcast and Multicast support

Yes

Broadcast is not supported. Various forms of Multicast are supported for a higher network bandwidth efficiency.

QoS support

ToS using DIFFServ

Flow labels and classes