Extended VLAN Subscriber Identification in DSLAM Ethernet Networks
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Solution Overview
Problem
Existing systems face difficulties in directing subscriber traffic to a given feature server, identifying subscribers, and directing feature server traffic to subscribers without ambiguity, especially in Ethernet-based DSL access networks, due to limitations in DSLAM ID and port ID space, reverse mapping issues, and security concerns.
Innovation Solution
The implementation of an extended VLAN (E-VLAN) mechanism that uses a 20-bit VLAN ID/Service ID field, along with other tags, to uniquely identify DSL subscribers and their service instances, and encapsulates customer MAC addresses for secure tunneling over Ethernet networks, ensuring unambiguous traffic forwarding and supporting multipoint applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If traditional VLAN ID space (12-bit) is used for identifying subscribers in Ethernet-based DSL access networks, then the system can operate with standard VLAN protocols, but the system cannot support more than 4096 service instances due to ID space limitations
Solution Approach 1:
The patent transitions from a 12-bit VLAN ID space to a 20-bit extended VLAN ID space, effectively adding another dimension of identification capacity. This allows the system to support up to one million service instances instead of being limited to 4096, while maintaining compatibility with existing VLAN protocols through the use of extended tag formats.
2Reliability
If MAC address translation is used to identify subscribers, then subscriber identification can be achieved, but reverse mapping problems and security issues arise
Solution Approach 1:
The patent extracts the subscriber identification function from MAC address translation and implements it through extended VLAN ID fields. By separating the identification mechanism from the address translation mechanism, the system achieves reliable subscriber identification without the reverse mapping problems and security vulnerabilities inherent in MAC address translation approaches.
3Reliability
If separate virtual circuits are allocated for each subscriber in ATM networks, then unambiguous traffic forwarding is achieved, but the system cannot efficiently support Ethernet-based access networks
Solution Approach 1:
The patent creates a universal identification mechanism that works across both ATM and Ethernet networks. The extended VLAN ID field serves multiple functions: it provides unambiguous subscriber identification like ATM virtual circuits, while simultaneously maintaining compatibility with Ethernet networking standards. This multi-functional approach allows the system to support Ethernet-based DSL access networks without sacrificing traffic forwarding accuracy.
Data Source
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AI summary
Identifying and forwarding traffic to/from Digital Subscriber Line Access Multiplex (DSLAM) devices and feature servers without ambiguity includes a user-facing provider edge (u-PE) device that receives a customer frame from a DSLAM device, the customer frame of a first format including a first virtual local area network (VLAN) tag of a first bit length. The first VLAN tag identifies a DSL subscriber. The customer frame is re-formatted by the u-PE device such that the first VLAN tag is mapped to a second VLAN tag of a second bit length greater than the first bit length, the second VLAN tag identifying a service instance of the Ethernet access network. The u-PE device encapsulating the customer frame inside a provider frame, with a provider source Media Access Control (MAC) address represents a MAC address associated with the DSLAM, and a provider destination MAC address represents a MAC address of a destination device.