Periplus, an in-band SDN control plane designed to address four challenges that this approach presents in such contexts: automatic bootstrapping, source-based routing, fast failure recovery, and multi-controller coordination is presented.
Abstract
Many resource-constrained, wide-area telecommunications deployments could benefit from an in-band SDN control plane, but several challenges stand in the way. This paper presents Periplus, an in-band SDN control plane designed to address four challenges that this approach presents in such contexts: automatic bootstrapping, source-based routing, fast failure recovery, and multi-controller coordination. The first three are developed in detail, while multi-controller coordination is addressed in a separate paper. For bootstrap, Periplus avoids network-wide flooding: when a new switch joins, the controller installs flow rules in only two switches. For routing and failure recovery, Periplus encodes a primary path and per-hop alternatives in a graph structure encapsulated between L2 and L3 headers; switches forward along the primary path and, upon detecting a failure, fall over locally to the encoded alternative without controller involvement. We evaluate a Ryu-based implementation of Periplus in Mininet across multiple topologies. Periplus runs on stock Open vSwitch (OVS), relying only on its built-in Nicira extensions for Network Service Header (NSH) encapsulation. The evaluation shows sub-50 ms failure recovery, scalable bootstrap across topologies of varying size and diameter, and a per-switch flow-table footprint that is independent of network size and grows only at switches where the controller encodes multiple alternatives.
In-band SDN control planes, where control traffic shares the data-plane infrastructure, suit wide-area, resource-constrained deployments -- such as rural backbones -- that cannot afford a dedicated control network. Partitioning such a network across multiple controllers improves scalability but raises a coordination challenge that in-band designs have largely ignored: controllers must discover one another and exchange state in-band, and switches must recover when their controller fails, all without forwarding state that grows with the number of controllers. This paper presents the multi-controller coordination plane of Periplus, an in-band control plane whose single-controller design is developed in a companion paper. Periplus controllers discover their neighbors through Controller Advertisement (C-Adv) messages and build inter-controller routes incrementally: each border switch inserts a partial forwarding graph covering only the next domain, so per-controller forwarding state is confined to border switches and never distributed across the interior of an intermediate domain. The same C-Adv mechanism reattaches a switch to a surviving controller after a controller failure. We evaluate a Ryu-based implementation in Mininet, including a 96-switch, 5-controller scenario. Per-switch flow-table state is set by a switch's role rather than by network size -- interior occupancy stays constant as controllers are added -- partitioning scales bootstrap to networks of around a hundred switches, and inter-controller discovery converges within seconds. The design needs no switch-firmware modifications: it runs on stock Open vSwitch, using only its built-in Nicira extensions for Network Service Header (NSH) encapsulation.
E. M. C. Barbero, P. Quirós, F. J. S. Reigadas· 0 citations
Software-Defined Networking (SDN) has become a major facilitator to flexible and programmable network operation; nevertheless, the extension of the control plane to handle big networks with heterogeneous networks has remained a core issue. The proposal presented in this paper is a design of a scalable control plane in a large SDN that can overcome the constraints of the centralized and fixed multi-controller designs. The suggested architecture takes the form of hierarchical and multi-controller structure with dynamically clustering and federation techniques to provide elasticity, fault tolerance, and effective use of resources. An assignment-based strategy to load-aware controllers is presented to dynamically assign switches to controllers in regard to real-time traffic intensity, control workload, and latency constraints whereas seamless controller migration ensures continuity of services in the face of network dynamics. The control plane also uses flow rule partitioning and aggregation to decrease state overhead and minimize redundant control operations in order to further ensure scalability. There is control message batching, adaptive poll, event based update and they are combined to reduce signaling overhead and enhance responsiveness by a large margin. A latency-aware controllerswitch mapping algorithm is also used to minimize control path delays to get rule installation and network convergence on time. Extensive performance analysis shows that the proposed design is almost linearly scalable as the network size is increased, and control latency is significantly lower and throughput is much higher than traditional SDN control plane designs. These findings affirm that the suggested scalable control plane is practical in supporting large scale SDN implementation and is therefore applicable in future carrier grade, data center and wide area network deployments at realistic workloads with varying topological setups in the modern programmable networks in the world.
A. Nagadeepan, Vishakha Abhay Gaidhani, Bhambare Rajesh et al.· Journal of Intelligent Decis...· 0 citations
Software-Defined Networking (SDN) provides a highly programmable architecture specifically by decoupling the control plane from the data plane. The efficiency of the controller in mapping topologies and responding to link failures depends heavily on the shortest-path algorithm used. While previous studies have evaluated algorithms like Bellman-Ford in small scale SDN, empirical comparisons with hybrid algorithms like Johnson in medium-scale dense topologies remain significantly limited. This study aims to provide an empirical comparative evaluation of Johnson and Bellman-Ford algorithms on OpenFlow 1.3 using the RYU controller, analyzing scalability across ring (sparse) and full-mesh (dense) topologies from 10 to 50 nodes. The research methodology relies on experimental emulation using Mininet to test convergence time, throughput, and recovery time during dynamic link failures. The results indicate that in sparse ring topologies, both algorithms achieve similar convergence under 0,06 seconds. However, in dense 50 node full-mesh networks containing 2.450 links, Bellman-Ford demonstrates a faster average convergence of 37,93 seconds compared to Johnson's 47,44 seconds, primarily due to the absence of graph reweighting overhead, despite exhibiting higher variance. Both algorithms maintained stable throughput, and while recovery times generally met the near carrier-grade standard, some scenarios in dense networks reached 60 milliseconds, slightly exceeding the 50 ms threshold. This study evaluates recovery during single link failure scenarios. In conclusion, Bellman-Ford is highly recommended for dense data center infrastructures, while Johnson is optimal for sparse networks requiring instant route recovery.
The proposed Multi-Path Multi-Level Feedback Queueing (MP-MLFQ) leverages the spatial diversity and regularity of DCNs to realize a scheduler with numerous logical priority levels while occupying as low as 2 physical priority queues within network switches.
Alessandro Cornacchia, Andrea Bianco, Paolo Giaccone et al.· 0 citations