VPLS Emulation Over ATM Networks Using PNNI
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Solution Overview
Problem
Service providers face challenges in implementing Virtual Private LAN Service (VPLS) over Asynchronous Transfer Mode (ATM) networks, as existing methods require costly MPLS signaling or tedious manual configuration of virtual channels, and there is no means to automatically establish a mesh of connections between Provider Edge devices.
Innovation Solution
The method involves configuring VPLS IDs at Provider Edge devices, exchanging ATM addresses, and establishing virtual circuits using PNNI Topology State Elements or Augmented Routing to create a mesh of connections automatically, allowing nodes to advertise supported VPLS IDs and set up virtual circuits without manual configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If MPLS signaling protocol is added to ATM network to implement VPLS, then VPLS service can be provided, but network cost and operational complexity increase
Solution Approach 1:
The patent introduces an intermediary mechanism by mapping VPLS IDs to ATM addresses and using PNNI routing protocol as a mediator to automatically establish virtual circuits. This intermediary layer enables VPLS service over ATM without requiring direct MPLS integration, thus reducing network complexity while maintaining service capability
Solution Approach 2:
The patent replaces the mechanical addition of MPLS signaling protocol with a software-based mapping mechanism. By substituting the need for MPLS hardware/signaling with a software mapping table and PNNI protocol utilization, the solution reduces operational complexity and cost while achieving the same VPLS service outcome
2Reliability
If manual configuration of virtual channels is performed for each pair of PEs, then VPLS connections can be established, but configuration time and operational effort increase
Solution Approach 1:
The patent implements self-service by enabling PE devices to automatically advertise their VPLS ID and ATM address information through PNNI protocol, and automatically establish virtual circuits based on this advertised information. This eliminates the need for manual configuration while ensuring reliable connection establishment
Solution Approach 2:
The patent applies preliminary action by pre-configuring the mapping between VPLS IDs and ATM addresses at each PE device before service deployment. This preliminary mapping information is then automatically exchanged and used to establish virtual circuits, eliminating the need for time-consuming manual configuration of each connection
3Ease of manufacture
If PNNI peer group hierarchy is used for ATM network routing, then routing is standardized, but VPLS ID information cannot be advertised outside peer groups
Solution Approach 1:
The patent solves the peer group limitation by adding another dimension to information advertisement: while PNNI handles routing at the network layer, the patent adds an application layer dimension where VPLS ID and ATM address mapping information is advertised alongside routing information. This multi-dimensional approach allows VPLS service capability to extend beyond peer group boundaries while maintaining PNNI standardization
Data Source
AI summary
A method and apparatus for emulating VPLS within an ATM network. Provider Edge devices are configured for VPLS connections. For each pair of provider edge devices supporting the same VPLS ID, one device establishes a virtual circuit between the pair. Thus, a full mesh of virtual circuits is established between provider edge devices, and a VPLS-like service can be offered to users without having to implement MPLS. Establishing the virtual circuits within a PNNI hierarchy maybe facilitated by each provider edge device propagating through the hierarchy an information group containing an association between the ATM address of the device and a VPLS ID, so that each provider edge device learns all ATM addresses to be associated with each VPLS ID. The method of advertising ATM addresses can be applied to other services requiring a number of interconnections between provider edge devices, such as Virtual Private Networks.