IPv6 in SA

Internet Protocol version 6 (IPv6) is a Layer 3 network protocol in the TCP/IP stack of protocols. IPv6 expands the number of network address bits from 32 bits (in IPv4) to 128 bits. The Internet Engineering Task Force (IETF) designed the IPv6 addressing scheme to provide interoperability with existing IPv4 network architecture and to allow the coexistence of IPv6 networks with existing IPv4 networks (see RFC 4291).

IPv6 solves the IP address shortage problem in IPv4, and it enhances and improves some of the salient features of IPv4. IPv6:

  • Enhances routing and addressing capabilities
  • Simplifies the IP header
  • Supports various types of IP addresses and larger address blocks for use with multicast routing

IPv4/IPv6 dual stack implementation

The dual-stack protocol implementation in an operating system is a fundamental IPv4-to-IPv6 transition technology. It implements IPv4 and IPv6 protocol stacks independently or in a hybrid form.

Hybrid dual-stack IPv6/IPv4 implementations support a special class of addresses, the IPv4-mapped IPv6 addresses. This address type has its first 80 bits set to 0, the next 16 bits set to 1, and the last 32 bits set to an IPv4 address. These addresses are commonly represented in the standard IPv6 format but have the last 32 bits written in customary IPv4 dot-decimal notation of IPv4; for example: ffff:192.0.2.128 represents the IPv4 address 192.0.2.128.

SA uses the dual-stack concept for SA core and satellite. Both SA core and satellite require an IPv4 address as well as an IPv6 address; these addresses can be on a single Network Interface Card (NIC) or on two NICs. The reason is that only the SA gateway components are IPv6-enabled, and all other SA core and satellite components are IPv4 only (except for those components accessed directly by agents, such as OGFS, NFS, and Samba).

IPv6 support

When the SA Core or satellite is IPv6-enabled, the managed servers will be able to register to the core with their IPv6 addresses and communicate to the core or satellite using the IPv6 protocol. SA core components that directly or indirectly communicate with the managed servers will be able to recognize the IPv6 addresses of managed servers and facilitate IPv6 communication from core to managed servers and vice versa.

Intra-core communication occurs through IPv4.

The agent and satellite gateway uses its IPv6 address to advertise its IPv6 capability but will uses its IPv4 address for most of its communication.

SA Agent installation

The SA Agent is supported in an IPv4, IPv6, and dual-stack network. The management IP for agents on managed servers is chosen at agent installation time by specifying the SA Gateway address as either (a list of) IPv4 or IPv6 address(es). If both IPv4 and IPv6 addresses are passed, they are tried in the same sequence in which they passed, and the first successful connection determines the management IP.

OS Provisioning

OS Provisioning supports IPv4, IPv6, and dual-stack networks.

In IPv6 networks, routing information is configurable only through router advertisement (RA) messages. To use DHCPv6 for addresses and other info, RA must be used for routing configuration.