Part I. What is IPv6?
Before learning IPv6, we should first know IP. IP is the abbreviation of Internet Protocol. IP addresses are generated according to the rules of IP protocols. It’s the address of terminals such as mobile phones and computers on the Internet and is the unique identifier of cyberspace terminals. Then, IPv6 is the abbreviation of Internet Protocol Version 6. It is a globally recognized next-generation Internet business application solution. It is the next-generation Internet protocol version formulated by the International Standardization Organization IETF to solve the exhaustion of IPv4 addresses. It can provide massive network address resources and Broad room for innovation. After a long period of coexistence of IPv4 and IPv6, IPv6 will eventually completely replace IPv4 and occupy a dominant position on the Internet.
Part II. Compared with IPv4, why is IPv6 better?
Compared with IPv4, IPv6 has the following characteristics, which can also be called the advantages of IPv6: simplified header and flexible expansion, hierarchical address structure, plug-and-play networking, authentication and encryption at the network layer, meeting the requirement of service quality, better support for mobile communication.
1. Simplified header and flexible extension
IPv6 simplifies the data header to reduce processor overhead and save network bandwidth. The header of IPv6 is composed of a basic header and multiple extension headers (ExtensionHeader). The basic header has a fixed length (40 bytes) and contains information that all routers need to process. Since most packets on the Internet are simply forwarded by routers, a fixed header length helps speed up routing. At the same time, IPv6 also defines a variety of extended headers, which makes IPv6 extremely flexible, can provide strong support for various applications, and at the same time provide the possibility to support new applications in the future. Except for the hop-by-hop options header (which carries information that must be processed by every node along the transmission path), the extension header will only be processed when it reaches the destination node specified in the IPv6 header (when In the case of multicast, it is each specified destination node). A complete IPv6 implementation includes the implementation of the following extension headers: one-by-one hop option header, destination options header, routing header, segmentation header, identity authentication header, payload security encapsulation header, and final destination header.
2. Hierarchical address structure
IPv6 expands the existing IP address length by 4 times, from the current 32 bits of IPv4 to 128 bits, to support a large number of network nodes. In this way, the total number of IPv6 addresses is about 3.4*10E38. IPv6 supports more levels of address hierarchy. The designers of IPv6 divide the IPv6 address space according to different address prefixes and adopt a hierarchical address structure to facilitate the rapid forwarding of data packets by backbone network routers. IPv6 defines three different address types. They are UnicastAddress, MulticastAddress, and AnycastAddress respectively. All types of IPv6 addresses belong to interfaces rather than nodes. An IPv6 unicast address is assigned to a certain interface, and an interface can only belong to a specific node, so the unicast address of any interface of a node can be used to identify the node.
3. Plug-and-Play networking
IPv6 takes the function of automatically assigning IP addresses to users as a standard function. As long as the machine is connected to the network, the address can be automatically set. It has two advantages. One is that the end user does not need to spend energy to set the address, and the other is that the burden of the network administrator can be greatly reduced. IPv6 has two automatic setting functions. One is a function called “full state automatic setting” which is the same as the IPv4 automatic setting function. The other is the “stateless automatic setting” function.
4. Authentication and encryption at the network layer
Security issues are always an important topic related to the Internet. Since security was not considered at the beginning of the IP protocol design, unfortunate things such as attacks on enterprise or institutional networks and theft of confidential data often occurred on the early Internet. In order to strengthen the security of the Internet. In 1995, IETF began to study and formulate a set of IP security (IPSec) protocols for protecting IP communication. IPSec is an optional extension protocol of IPv4 and a necessary part of IPv6. The main function of IPSec is to provide security services such as encryption and authentication for data packets at the network layer. It provides two security mechanisms: authentication and encryption. The authentication mechanism enables the data receiver of IP communication to confirm the true identity of the data sender and whether the data has been changed during transmission. The encryption mechanism guarantees the confidentiality of the data by encoding the data, so as to prevent the data from being intercepted by others during transmission. The authentication header (AuthenticationHeader, AH) protocol of IPSec defines the application method of authentication, and the security load encapsulation (EncapsulatingSecurityPayload, ESP) protocol defines the application method of encryption and optional authentication. In actual IP communication, you can use these two protocols at the same time or choose to use one of them according to the security requirements. Both AH and ESP can provide authentication services, but the authentication service provided by AH is stronger than that of ESP.
5. Meet the requirement of service quality
At the beginning of the design of the IPv4-based Internet, there is only one simple quality of service, that is, the use of “best effort” transmission. In principle, the quality of service QoS is not guaranteed. With the increase of multimedia services on the IP network, such as real-time applications such as IP telephony, VoD, and video conferencing, there are strict requirements on transmission delay and delay jitter.
The format of the IPv6 data packet includes an 8-bit service flow class (Class) and a new 20-bit flow label (Flow Label). The 4-bit priority field was first defined in RFC1883, which can distinguish 16 different priorities. It was later changed to an 8-bit category field in RFC2460. Its value and how to use it have not been defined yet. Its purpose is to allow the source node sending the service flow and the router forwarding the service flow to add a mark on the data packet and perform different processing except the default processing.
A flow is a series of packets related in some way, and the IP layer must treat them in a related way. The parameters that determine that information packets belong to the same flow include source address, destination address, QoS, identity authentication and security. The introduction of the concept of flow in IPv6 is still based on the connectionless protocol. A flow can contain several TCP connections, and the destination address of a flow can be a single node or a group of nodes. When an IPv6 intermediate node receives an information packet, it can determine which flow it belongs to by verifying its flow label, and then it can know the QoS requirements of the information packet and perform fast forwarding.
6. Better support for mobile communication
Mobile communication plays an important role in our life. The mobile Internet is not just mobile access to the Internet. It also provides a series of value-added services with mobility as the core: inquiry of localized design information, remote control tools, unlimited interactive games, shopping payment, etc. The design of Mobile IPv6 draws on the design experience of Mobile IPv4 and utilizes many new features of IPv6, so it provides more and better features than Mobile IPv4.
Part III. Does V-SOL’s product support IPv6?
V-SOL has been trying to meet the demands of users and keeps up with the latest technological development. Although it’s difficult for some device manufacturers to achieve access to the IPv6 network, V-SOL’s product including OLT, ONU, and Ethernet switch supports both IPv4 and IPv6. For example, the following images are respectively ONU and OLT that support IPv4 and IPv6.
Upgrading from IPv4 to IPv6 is inevitable. Some operators may not replace IPv4 with IPv6 due to the cost and compatibility at present, but it’s believed that IPv6 will dominate.