Recovery and Reconstruction of Multicast Tree in Software-Defined Network: High Speed and Low Cost

Jue Chen,Dongmei Li,Xihe Qiu,Shanshan Chen,Fengting Yan

doi:10.1109/access.2020.2970275

Abstract

Multicast is an efficient tool to transfer the same data from a publisher to multiple subscribers, and its performance relies critically on the resiliency. Compared with traditional networks, the centralized control and flexible programmability of the Software Defined Network (SDN) is more beneficial for solving the failure recovery problem. This paper presents a design of an OpenFlow controller which can recover and reconstruct a multicast tree rapidly, while reducing the Ternary Content Addressable Memory (TCAM) consumption simultaneously. We choose the protection mechanism, and calculate all the backup paths after the topology information is mastered by the controller. When a failure occurs, affected switches can enable the use of backup paths to continue forwarding multicast packets. As duplicate packets may exist after the failure recovery, the reconstruction of a tree is required by modifying only a small fraction of forwarding rules. The performance evaluations demonstrate that our proposed method recovers a multicast tree with a high speed and low cost. On one hand, the maximum failure recovery time of two protection-based methods including our proposed method is less than 11 ms, while that of two restoration-based methods is 44 ms and 30 ms, respectively. On the other hand, the amount of backup forwarding entries required by another protection-based method exceed our proposed method as long as 3 or more multicast groups exist in the network. Moreover, when our proposed method is adopted, the amount of backup forwarding entries per switch is less than 30, which can be ignored when compared with the capacity of SDN switches (a switch can support a few thousand forwarding rules).

Highlights

In order to transfer the same data from a publisher to multiple subscribers, two naive approaches can be applicable, either by flooding the packet to all hosts or by cloning the packet at the source and forward each clone to one destination [1]
This paper proposes a set of methods to realize the recovery and reconstruction of multicast trees with a high speed and low cost, and the main contributions and novelties of our proposed method are summarized as follows
This paper proposes a set of methods to realize fast failure recovery and reconstruction of multicast trees, which are composed of three phases as listed below: 1) Preparation of Backup Path 2) Calculation of Multicast Tree 3) Reconstruction of Multicast Tree

Summary

INTRODUCTION

In order to transfer the same data from a publisher to multiple subscribers, two naive approaches can be applicable, either by flooding the packet to all hosts or by cloning the packet at the source and forward each clone to one destination [1]. Kotani et al [3] prepare two disjoint trees for each multicast group, and Gyllstrom et al [13] assign a subtree for each link of the primary multicast tree When these two methods are adopted, the controller only needs to modify one flow entry after a failure, and the recovery time is decreased compared with the method proposed by Raja et al [2]. It can be inferred that among these four methods, the last one can promise the highest speed of failure recovery, but will lead to a huge cost on TCAMs for storing backup paths, as each multicast group corresponds to multiple backup trees and all the backup trees need to be calculated and established on switches in advance.

PREPARATION OF BACKUP PATH

CALCULATION OF MULTICAST TREE

RECONSTRUCTION OF MULTICAST TREE

Findings

VIII. CONCLUSION