2024+IPv6技术白皮书

Industry Overview - IPv6 is the second-generation standard protocol for the network layer, designed to address the limitations of IPv4, particularly the exhaustion of address space. It introduces improvements such as extended headers for better scalability and built-in security features [9] - IPv6 supports a vast address space of 128 bits, providing over 3.4×10^38 addresses, which is sufficient to meet the demands of the Internet of Things (IoT) and other emerging technologies [10] - The hierarchical address structure of IPv6 simplifies address management and enhances routing efficiency by allowing organizations to allocate addresses in a more granular manner [11] Technical Advantages of IPv6 - IPv6 simplifies the packet header by reducing its size to 40 bytes, compared to IPv4's 20 bytes, which improves forwarding efficiency [13] - The protocol introduces flexible extension headers, allowing for better customization and scalability without the limitations of IPv4's 40-byte option field [15] - IPv6 incorporates a robust Neighbor Discovery Protocol, which replaces ARP and provides features like address resolution, neighbor reachability detection, and duplicate address detection [24] - Built-in security features, such as ESP and Authentication headers, provide end-to-end security, reducing the complexity of application-level security implementations [27] Protocol Extensions Based on IPv6 - IPv6 supports global unicast address configuration through manual configuration, stateless address autoconfiguration, and stateful address autoconfiguration (DHCPv6) [29] - Stateless address autoconfiguration allows devices to generate their own IPv6 addresses using network prefixes obtained from Router Advertisement (RA) messages [31] - DHCPv6 offers more control over address allocation and can assign additional network parameters like DNS server addresses, making it suitable for environments requiring strong access control [44] IPv6 Routing Protocols - RIPng, OSPFv3, IPv6 IS-IS, and IPv6 BGP are extensions of their IPv4 counterparts, adapted to support IPv6 addressing and routing [75] - RIPng uses multicast for routing updates and eliminates the need for authentication fields by leveraging IPv6's built-in security mechanisms [83] - OSPFv3 operates on a per-link basis, supports multiple instances on the same link, and uses link-local addresses for communication, making it more flexible than OSPFv2 [88] - IPv6 BGP introduces new path attributes like MP_REACH_NLRI and MP_UNREACH_NLRI to support IPv6 routing over both IPv4 and IPv6 sessions [113] IPv6 Multicast - IPv6 multicast addresses are structured to include flags, scope, and group ID fields, allowing for more precise control over multicast group membership and scope [122] - Reserved IPv6 multicast addresses, such as all-nodes and all-routers addresses, are predefined for specific purposes like neighbor discovery and router communication [128] - IPv6 multicast supports dynamic address allocation based on unicast prefixes, ensuring globally unique multicast addresses [130] IPv6 Deployment Strategies - Dual-stack strategy routing allows for simultaneous handling of IPv4 and IPv6 traffic, reducing configuration complexity and conserving resources [117] - IPv6 multicast protocols, such as PIM (Protocol Independent Multicast), are extended to support IPv6, enabling efficient data delivery to multiple recipients in IPv6 networks [120]