Dynamic VLAN Sub-Interface Building via Upper-Layer Protocol Extraction
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Solution Overview
Problem
Service provider networks migrating from ATM to Ethernet infrastructures face challenges in distinguishing between multiple subscriber devices without VLAN identification (VID) tags, limiting the ability to deliver subscriber-specific services.
Innovation Solution
Network devices dynamically build Ethernet VLAN interfaces based on subscriber information strings and use upper-layer protocol information to forward data packets to the correct subscriber VLAN sub-interfaces, even if VID tags are absent, by accessing and utilizing IP host tables and session tables.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If VLAN identification (VID) tags are used in Ethernet frame headers to identify subscriber devices, then the ability to distinguish between multiple subscriber devices is improved, but device complexity and infrastructure requirements increase
Solution Approach 1:
The patent extracts the subscriber identification function from the Ethernet frame header (VID tag) and relocates it to the IP packet payload. Specifically, subscriber information strings are placed in IP options fields or upper-layer protocol data, allowing identification without modifying the Ethernet layer structure. This separation maintains Ethernet simplicity while enabling precise subscriber identification at the network layer.
Solution Approach 2:
The patent moves the identification mechanism from the data link layer (Ethernet VID tags) to the network layer (IP packet contents). By examining upper-layer protocol information such as IP options, source/destination addresses, or application-layer data, the system identifies subscriber devices without requiring changes to the Ethernet frame structure, effectively solving the contradiction by operating in a different protocol dimension.
2Device complexity
If VID tags are excluded from Ethernet frame headers to simplify infrastructure, then device complexity is reduced, but the ability to distinguish between multiple subscriber devices deteriorates
Solution Approach 1:
The patent introduces upper-layer protocol information as an intermediary carrier for subscriber identification. Instead of directly using VID tags in Ethernet frames, the system embeds subscriber information strings within IP packets (such as in IP options, source addresses, or upper-layer protocol data). This intermediary mechanism allows subscriber differentiation without modifying the Ethernet layer, maintaining infrastructure simplicity while preserving identification accuracy.
Solution Approach 2:
The patent performs preliminary extraction and storage of subscriber identification information during packet reception. The system pre-processes incoming packets to extract subscriber information strings from upper-layer protocols and stores them in forwarding information bases (FIBs) or routing tables. This preliminary action enables subsequent forwarding decisions to be made based on pre-extracted identification data, eliminating the need for VID tags while maintaining accurate subscriber distinction.
3Adaptability or versatility
If dynamic VLAN interface building based on subscriber information strings is implemented, then adaptability to different subscriber configurations is improved, but device complexity increases
Solution Approach 1:
The patent implements dynamic VLAN sub-interface creation based on real-time extraction of subscriber information from incoming packets. When a packet with a new subscriber information string is received, the system automatically creates corresponding VLAN sub-interfaces and populates forwarding tables with appropriate mappings. This dynamic approach allows the network to adapt to diverse subscriber configurations without pre-configuration, with the complexity managed through automated interface creation and table population mechanisms.
Data Source
AI summary
Techniques are described that allow a network device, such as a router, to forward data packets received from a subscriber device to an Ethernet virtual local area network (VLAN) interface within the network device where the VLAN interface has been dynamically built based on a subscriber information string. For example, a primary VLAN sub-interface (PVS) and a subscriber VLAN sub-interface (SVS) may each be dynamically built over a statically built VLAN major interface. In particular, the network device comprises a forwarding controller, where the forwarding controller receives a data packet over an Ethernet port. The network device accesses upper-layer protocol information within the data packet to determine an SVS within the network device to which to forward the data packet based on the upper-layer protocol information.