Abstract
To empower advanced traffic engineering (TE) mechanism, while considering the infeasibility of one-step migration to software-defined networking (SDN), SDN nodes are incrementally deployed into legacy network, which gives rise to hybrid SDN. In hybrid SDN, redirecting flow of every source-destination pair through at least one SDN node, can enhance TE performance and obtain flow manageability, while on the other hand leading to increasing demands of TCAM resources in SDN nodes. In this paper, we make minimization of maximum link utilization as the TE objective, and comply with SDN waypoint enforcement and TCAM resource limitation. We first formulate the TE problem as an integer linear programming (ILP) model and solve it in a centralized manner, where SDN waypoint selection and splitting fractions for each flow are jointly determined. Then, based on a fact that the logically centralized control plane in hybrid SDN is composed of multiple physically decentralized controllers, each of which manages part of SDN nodes, as well as considering a real situation that a centralized solution is infeasible or too fragile for large-scale network, we develop a distributed algorithm deriving from Lagrangian decomposition theory to effectively solve the TE problem. The simulation results indicate that, when 30% of the SDN nodes are deployed, the proposed traffic engineering-aware distributed routing (TEDR) algorithm obtains maximum link utilization comparable to that of full SDN, and has a limited influence on the routing efficiency.
Highlights
Software Defined Networking (SDN) is an emerging network paradigm
2) We propose a decomposability structure for the formulated traffic engineering (TE) problem based on the duality and decomposition theory, which can lead to a distributed algorithm that converges to a global optimum using distributed computation over the network [11], and the resulting distributed algorithm exactly caters to the practical needs of the evolved hybrid SDN whose control plane operates as a distributed system
Since the work in this paper focuses on flow manageability by rerouting each flow originating from legacy node through an elaborately calculated SDN waypoint, the approach proposed in [23] can be used as an available method to fulfill the flow redirection operation
Summary
Software Defined Networking (SDN) is an emerging network paradigm. It enables unprecedented programmability and network management flexibility through the separation of network control and forwarding planes. Panopticon [20] uses VLAN mechanism and layer 2 routing protocol STP to make every packet traverse at least one SDN node enabling end-to-end network policy It does not discuss the appropriate SDN node selection for every source-destination pair which may result in an non-optimal TE performance. It brings relatively inflexible routing and overheads of too many VLAN IDs. Fibbing [21] generates a fake topology to indirectly change the shortest path utilizing fake LSAs in conventional IP networks. Telekinesis [22] is similar with Fibbing that injects fake and harmless messages into the network leveraging MAC learning It enables finer-grained routing control over legacy paths at layer 2 in hybrid SDN by making paths traverse SDN nodes. With respect to the specific method to fulfill the waypoint enforcement, Panopticon [20], Fibbing [21], Telekinesis [22] and ACL policies implementation approach [23] can be the suitable methods in this paper to redirect every flow originating from a legacy node through a well-calculated SDN waypoint
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