Path Protection in Connection-Oriented Packet Switched Networks
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Solution Overview
Problem
Current protection mechanisms in Connection Oriented-Packet Switched (CO-PS) networks, such as VRRP, require complex redundancy management and involve the core network in fault detection and switching, increasing cost and complexity, especially when dealing with multicast video services that demand high bandwidth.
Innovation Solution
Implementing a method that sets up connection-oriented worker and protection paths between distribution nodes and access nodes, allowing traffic to be switched between these paths without involving the upstream node in protection mechanisms, reducing complexity and cost by using a connection-oriented interface path for communication and control messages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If VRRP protection mechanism is used in CO-PS networks, then network protection capability is provided, but device complexity and cost increase due to core network involvement and complex redundancy management
Solution Approach 1:
The patent segments the protection mechanism into two independent parts: (1) fault detection within the CO-PS network using Layer 2 protection mechanisms, and (2) traffic switching between worker and protection trees. This eliminates the need for core network involvement in fault detection while maintaining protection capability, thereby reducing device complexity and cost.
Solution Approach 2:
The patent introduces an intermediary protection mechanism at the edge of the CO-PS network that mediates between the core network and the metro network. This intermediary handles fault detection and traffic switching locally, preventing complex redundancy management from propagating to core network devices while maintaining end-to-end protection.
2Reliability
If VRRP is used with Ethernet tree configuration, then protection is provided, but complexity increases due to requiring two worker trees and two protection trees to be configured and managed
Solution Approach 1:
Instead of having the core network manage multiple protection trees, the patent inverts the approach by implementing protection switching at the edge of the CO-PS network. This allows the network to use a single worker tree and single protection tree configuration, with the edge device handling the switching logic, thereby reducing configuration and management complexity.
3Reliability
If fault detection is propagated from Layer 2 to Layer 3, then core network protection is activated, but cost and complexity increase due to inter-layer communication requirements
Solution Approach 1:
The patent extracts the fault detection function from the core network (Layer 3) and places it at the edge of the CO-PS network (Layer 2). This extraction eliminates the need for complex inter-layer communication while maintaining end-to-end protection, as the edge device can detect faults and switch traffic without requiring core network involvement in the detection process.
Data Source
AI summary
The invention relates in general to a communications network, and more particularly, to methods and apparatus for protecting such a network. The methods and apparatus disclose the providision path protection in a communications network (14) having a plurality of nodes including at least one access node (24, 26, 28, 30). A connection-oriented worker path (23) is set up between a first distribution node (22) and the at least one access node. A connection-oriented protection path (21) is also set up between a second distribution node and the at least one access node. A connection-oriented interface path (52) is also set up between the first and second distribution nodes. Traffic from an upstream node (16, 18) is switched to the interface path (52) at one of the distribution nodes (20, 22). Traffic may be switched to the protection path (21) in response to detecting a fault (54) in the worker path.