Multi-layer Virtual Network Embedding via Collapsed Graph Optimization
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Solution Overview
Problem
Existing methods for virtual network embedding in multi-layer communication networks, such as IP-over-optical networks, face challenges in optimizing resource provisioning and minimizing the creation of new links, leading to suboptimal solutions and high costs.
Innovation Solution
A method that jointly determines the embedding of virtual nodes and links by formulating an objective function considering the cost of embedding, using a collapsed graph that combines optical and IP networks, and employing integer linear programming or heuristic methods like min-cost max flow algorithms to optimize resource allocation and link creation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If virtual network embedding is performed separately for each layer (IP and optical), then the implementation is simpler, but the solution becomes suboptimal and costs increase
Solution Approach 1:
The patent merges the separate embedding processes for IP and optical layers into a unified joint embedding process. The system formulates a single optimization problem that simultaneously determines virtual node placement and virtual link routing across both layers, considering their interdependencies. This integration enables the system to exploit topological flexibility from both layers together, achieving optimal resource allocation and minimizing total provisioning costs rather than treating each layer independently.
2Reliability
If joint embedding of virtual nodes and links is performed, then optimality improves, but computational complexity increases
Solution Approach 1:
The patent segments the joint embedding problem into two coordinated phases: first, virtual nodes are mapped to substrate nodes; second, virtual links are routed through the network. This segmentation allows the use of specialized algorithms for each phase (node mapping followed by link routing) while maintaining the benefits of joint optimization. The system uses integer linear programming for the overall framework with heuristic methods for specific subproblems, breaking down the complex computation into manageable components that can be solved efficiently.
3Adaptability or versatility
If more IP links are created to accommodate virtual networks, then network flexibility increases, but provisioning costs increase
Solution Approach 1:
The patent implements a dynamic link creation mechanism where the system evaluates whether to create new IP links or utilize existing ones based on real-time optimization criteria. The integer linear programming formulation includes decision variables that dynamically determine link creation versus reuse, considering current network state, virtual network requirements, and cost parameters. This dynamic approach allows the system to create new links only when necessary to achieve optimal embedding, rather than pre-provisioning all possible links, thus balancing flexibility with cost efficiency.
Data Source
AI summary
Some aspects and embodiments of the present invention provide effective mechanisms for provisioning virtual networks on communication networks. In particular some aspects and embodiments provide an effective mechanism for embedding a virtual network into a multi-layered substrate network which utilizes a different communication technology at each layer. One such example is an IP network overlaid over an optical network, such as an OTN network. Embodiments jointly determine the assignment of virtual nodes and virtual links. Assigning the nodes and links together can provide for a more optimal solution than assigning the nodes and the links separately. Some embodiments generate a collapsed graph which includes the optical network and the IP network in a single layer. Accordingly some embodiments jointly determine the assignment of virtual nodes and virtual links within such a collapsed graph, which can provide more optimal assignments than considering assignments within each layer separately. In some embodiments, generating a collapsed graph includes allocating residual capacity to each link of the collapsed graph; and allocating a cost for each link of the collapsed graph. In some embodiments, allocating a cost for each link includes allocating a higher cost to optical links than to IP links. In some cases, allocating the higher costs can discourage the creation of new links unless they are needed or are beneficial (e.g. creating new links improves the overall cost/efficiency). Some embodiments utilize a heuristic method for solving an optimization function for the placement of virtual nodes and links.