Tunneling Technology in IPv6 Networks

The tunnel technology is used to connect the two networks that are currently used by both protocols, that is, the IPv6 network and IPv4 network, to ensure compatibility. Now let's mainly analyze this technology.

Tunneling Technology

In the early stages of IPv6 development, there must be many local pure IPv6 networks, which are isolated by IPv4 backbone networks. In order to connect these isolated IPv6 islands, we will adopt the tunnel technology to solve the problem. The existing IPv4 internet tunneling technology is used to connect many "IPv6 isolated islands" and gradually expand the IPv6 Implementation scope. This is the current plan of the International IPv6 test bed 6Bone.

Working mechanism:

At the tunnel entrance between the IPv6 network and the IPv4 network, the router encapsulates the IPv6 Data Group into IPv4. The source address and destination address of the IPv4 group are the IPv4 addresses at the tunnel entry and exit respectively. At the exit of the tunnel, pull the IPv6 group and forward it to the target node.

Tunnel technology has four forms in practice:

Construct a tunnel

Automatic Tunnel Configuration

Multicast tunnel and 6to4

TBTunnelBroker, tunnel proxy)

For an independent IPv6 user, to connect to an IPv6 network through an existing IPv4 network, tunneling technology must be used. However, the scalability of Manual Tunnel Configuration is poor. The main purpose of TB is to simplify Tunnel Configuration and provide automatic configuration methods.

For ISPs that have already established IPv6, the use of TB technology provides a convenient way for network users to expand. In this sense, TB can be viewed as a virtual IPv6ISP, which provides users connected to IPv4 networks with the means to connect to IPv6 networks, users connected to IPv4 networks are TB customers.

Dual-stack conversion mechanism DSTM)

DSTM aims to achieve interconnection between the new IPv6 network and the existing IPv4 network. With DSTM, the dual-stack nodes in IPv6 can communicate with IPv4 hosts in an IPv4 network.

The basic components of DSTM include:

◆ DHCPIPv6 Server:

Assign a temporary unique IPv4 address for the dual-stack host in the IPv6 network, and keep the ing between the temporarily assigned IPv4 address and the IPv6 permanent address of the host, in addition, the tunnel end TEP of the IPv6 tunnel is provided;

◆ Dynamic tunnel Port:

Each DSTM host has an IPv4 port used to package IPv4 packets into IPv6 packets;

◆ Dmo-deamon:

Works with the DHCPIPv6 client to resolve the IPv6 address and IPv4 address.