IPv6 Prefix Delegation and Packet Filtering in Broadband Networks
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Solution Overview
Problem
Current mechanisms for IPv6 deployment in broadband networks lack specific solutions to meet the requirements for network interconnection, Quality of Service (QoS), bandwidth, and user experience, particularly in DSL technology, where IPv6 support is being introduced alongside IPv4.
Innovation Solution
The method involves sending a DHCP message with an Identity Association for Prefix Delegation (IA_PD) option containing an IPv6 prefix and length, receiving packets with source MAC and IPv6 addresses, and implementing IPv6 prefix mapping and filtering states at access nodes to manage packet flow and multicast listener discovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If IPv6 prefix delegation is implemented using DHCPv6 in broadband networks, then IPv6 address configuration and network interconnection are improved, but packet filtering and security control become more complex
Solution Approach 1:
The patent introduces an intermediary mapping mechanism that associates IPv6 prefixes with MAC addresses through a centralized table structure. This intermediary layer decouples the prefix delegation function from the packet filtering function, allowing the system to maintain simple filtering rules while supporting complex IPv6 address configurations through the mapping table that translates between prefixes and hardware addresses.
Solution Approach 2:
The patent segments the IPv6 deployment functionality into distinct components: prefix delegation via DHCPv6, prefix-MAC address mapping maintenance, and packet filtering based on mapping tables. This segmentation allows each component to be optimized independently, reducing overall system complexity while maintaining adaptability for IPv6 configuration.
2Reliability
If packet filtering is implemented based on MAC address and IPv6 prefix mapping, then network security and QoS control are improved, but processing overhead and device complexity increase
Solution Approach 1:
The patent implements preliminary action by pre-establishing the mapping between IPv6 prefixes and MAC addresses through DHCPv6 prefix delegation before actual data traffic occurs. The mapping table is populated in advance during the address configuration phase, so that subsequent packet filtering operations can simply query the pre-computed mapping rather than performing complex real-time analysis, thereby reducing processing overhead while maintaining security.
3Adaptability or versatility
If multicast listener discovery is supported in IPv6 networks, then network functionality and user experience are improved, but message forwarding complexity and device load increase
Solution Approach 1:
The patent extracts the multicast listener discovery functionality from the general packet forwarding path by implementing specific rules for multicast message handling. The system separates multicast traffic processing from unicast filtering, applying specialized forwarding logic only to multicast packets while maintaining simple filtering for other traffic types, thereby reducing overall device complexity while preserving multicast support.
Data Source
AI summary
A method comprising sending a dynamic host configuration protocol (DHCP) message comprising an Identity Association for Prefix Delegation (IA_PD) Prefix option comprising a Internet Protocol version 6 (IPv6) prefix and a length of the IPv6 prefix to a device having a media access control (MAC) address, receiving from the device a packet comprising a source MAC address and a source IPv6 address, and dropping the packet when the MAC address is equal to the source MAC address and the leftmost bits of the source IPv6 address defined by the length are not equal to the IPv6 prefix.