Network Protection Capacity Determination for Fast Restoration
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Solution Overview
Problem
Designing efficient protection schemes for mesh networks to achieve fast restoration times without the overbuild associated with ring-based SONET networks, which typically require 100% redundancy, is challenging, especially when protecting against multiple link failures.
Innovation Solution
A technique for determining the minimal protection capacity and bypass tunnels in a network topology, using methods such as spanning tree and 2-edge connected graph constructions, to ensure fast local restoration with minimal overbuild, allowing working traffic to be rerouted on at most two bypass tunnels, independent of traffic nature and routing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ring-based SONET networks use pre-reserved spare protection capacity and pre-planned protection paths, then fast restoration (50ms) is achieved, but 100% redundancy is required
Solution Approach 1:
The invention segments the protection mechanism into local bypass tunnels at each node rather than end-to-end protection paths. Each node independently establishes backup tunnels to adjacent nodes, allowing granular protection that reduces overall redundancy requirements while maintaining fast restoration capability.
Solution Approach 2:
The invention transitions from traditional end-to-end path protection to a multi-dimensional local protection approach where bypass tunnels operate at the node level across multiple dimensions of the network topology, enabling more efficient capacity sharing and reduced redundancy.
2Quantity of substance
If mesh networks use facility backup technique with bypass tunnels, then capacity sharing is improved, but protection against multiple link failures becomes challenging
Solution Approach 1:
The invention pre-establishes bypass tunnels between adjacent nodes before failures occur. These tunnels are proactively configured with reserved capacity, enabling immediate local restoration without waiting for failure detection or dynamic path computation, thus protecting against multiple failures efficiently.
Solution Approach 2:
The invention applies different protection strategies at different locations in the network. Local bypass tunnels provide fast protection for adjacent node failures, while other mechanisms handle more complex failure scenarios, creating a differentiated protection architecture that optimizes both capacity utilization and reliability.
3Reliability
If one-to-one backup technique is used in MPLS networks, then fast restoration is achieved, but the number of bypass tunnels becomes very large
Solution Approach 1:
The invention merges the protection functions of multiple one-to-one backup tunnels into shared facility backup tunnels. By combining protection capabilities at the facility level rather than service level, the number of required bypass tunnels is dramatically reduced while maintaining fast restoration capability.
Solution Approach 2:
The invention creates bypass tunnels that serve multiple purposes and protect multiple services simultaneously. A single bypass tunnel can protect multiple LSPs (Label Switched Paths) from the same node, making the protection mechanism universal and reducing overall tunnel count while maintaining protection effectiveness.
Data Source
AI summary
Improved network design techniques are provided. For example, a technique for designing a protection capacity to be reserved in a network comprises the following steps/operations. One or more link capacities associated with a network topology are obtained. The network is assumed to have no pre-existing working traffic. A capacity partition including a working capacity portion and a protection capacity portion is determined for at least one link in the network topology. The protection capacity portion is reserved for rerouting working traffic upon a failure and enabling control over the number of backup tunnels, associated with the at least one link, on which working traffic can be rerouted. Determining the capacity partition substantially guarantees at least one of a minimal failure restoration time and a minimal overbuild. A minimal overbuild may include an overbuild equivalent to no more than two times an overbuild required for an optimal solution.