See IPv6 network protocols for multiple services.

When we upgrade from IPv4 to IPv6, are we fully prepared? Otherwise, many people still have some opinions on the IPv6 network protocol. After all, we have no doubt about new things. However, this does not prevent IPv6 from moving forward. What are IPv6 network protocol considerations for better service quality?

From the Protocol perspective, the IPv6 network protocol and the current IPv4 provide the same quality of service QoS), but the advantages of IPv6 are that it can provide different services. These advantages come from the priority field and Flow Label field added in the IPv6 packet header structure. The priority field is extended to 1 byte, which defines the priority of 256 levels, and determines the priority of data packets based on various multimedia information, this ensures that each service can meet the quality of user satisfaction. With 20-bit long stream tag fields, each node in the middle can identify and process any IP address stream separately during transmission. In IPv6, all data packets of the same business flow use the same flow label. In this way, when the vro detects the same flow label, it uses the same path for sending, instead of selecting a route for each data packet, this greatly improves the efficiency of packet forwarding and reduces the end-to-end latency. Although no standards have been developed for the accurate application of flow tags, they will be used in new service-level billing systems in the future. In addition, IPv6 also helps improve service quality in terms of "always online" connections, service interruption prevention, and network performance improvement.

IPv6 QoS is the IETF Resource retention Protocol Resource Reserve Protocol, RSVP ). The RSVP used by the host to represent the application data stream refers to the stream of related data packets that can be identified by the router or the host that forwards the data. In IPv6, the stream has the same flow label) request a specific service quality from the network, such as the maximum bandwidth based on the average value, the maximum reception latency, the priority queue, and other parameters. The host can also specify a specific network service level, this is similar to the concept of the network information table in Digital Video broadcast Digital Video Broadcasting, DVB. RSVP uses this request to access each node of the network through the network. On each node, RSVP tries to reserve resources for the stream. This makes it possible to provide images with quality of service and other real-time services.

What is an IPv6 network protocol conversion mechanism? Why is a conversion mechanism required?

IPv6 cannot replace IPv4 immediately. Therefore, IPv4 and IPv6 will exist in an environment for a considerable period of time. A stable conversion process is required to minimize the impact on existing users. At present, this topic is the main objective of the IETF ngtrans team. Many Conversion Mechanisms have been proposed, and some have been used on 6Bone. IETF recommends two-protocol stack, tunnel technology, NAT, and other conversion mechanisms:

IPv4 and IPv6 Dual-protocol stack Technology

Simply put, the dual-stack mechanism enables IPv6 nodes to have an IPv4 stack and an IPv6 stack, and supports both IPv4 and IPv6 protocols. IPv6 and IPv4 are network-layer protocols with similar functions. Both of them are applied to the same physical platform and carry the same transport layer protocol TCP or UDP. If a host supports both IPv6 and IPv4 protocols, the host can communicate with a host that only supports IPv4 or IPv6. The protocol structure of the IPv6/IPv4 protocol stack is shown in:

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Tunneling Technology

To enable the communication between IPv4 and IPv6 protocols, the tunnel mechanism is to encapsulate IPv6 packets as data in IPv4 packets when necessary, enables IPv6 data packets to be transmitted on an existing IPv4 infrastructure, mainly an IPv4 router. With the development of IPv6, some local IPv6 networks are isolated by backbone networks running the IPv4 protocol. To achieve communication between these IPv6 networks, tunneling technology must be used. The tunnel is transparent to the source site and destination site. At the entrance of the tunnel, the router encapsulates the IPv6 Data Group in IPv4, the source address and destination address of the IPv4 group are the IPv4 addresses at the tunnel entry and exit respectively. At the tunnel exit, the IPv6 group is taken and forwarded to the destination site. The advantage of tunneling technology lies in the transparency of tunnels. Communication between IPv6 hosts can ignore the existence of tunnels. tunnels only serve as physical channels. Tunnel technology is widely used in the early stages of IPv4 to IPv6 evolution. However, tunnel technology cannot implement communication between IPv4 and IPv6 hosts;

Network Address Translation Technology

Network Address Translation (NAT) technology is to regard IPv4 addresses and IPv6 Network protocol addresses as internal addresses and global addresses, or vice versa. For example, when an internal IPv4 host needs to communicate with an external IPv6 host, the IPv4 address is equivalent to an internal address in the NAT server ), the server maintains a ing table between IPv4 addresses and IPv6 addresses. When the internal IPv6 host communicates with the external IPv4 host, the IPv6 host maps to the internal address, and the IPv4 host maps to the global address. NAT technology can solve the problem of intercommunication between IPv4 and IPv6 hosts.