軟體定義網路動態服務串鍊機制決定型服務品質保證之研究

Abstract

近年來，許多種類的網路服務 (Network Functions) 透過虛擬機器 (Virtual Machine) 方式建置成軟體網路服務，佈置於資料中心裡，如網路位 址轉換 (NAT)、防火牆 (Firewall) 等。在本篇論文中，我們發現服務串鍊 (Service Chain) 延遲保證的問題，並且提出動態改變服務串鍊路徑的策略。 為了達到服務串鍊的延遲保證之目的，我們分析控制器及軟體網路服務，並 將此服務串鍊問題模組成具限制條件之最短路徑問題。我們提出延遲保證服 務串鍊機制，同時也將該機制實作於 OpenFlow 網路中之集中式控制器。在 此架構下，當有網路拓樸改變或是突爆性網路流量發生時，我們能動態的監 控網路資訊，並且重新修改服務串鍊之路徑，使其能符合使用者之延遲需求。

In recent years, various network services are deployed in datacenters through virtual machine (VM), such as network address translation (NAT), firewall, etc. Multiple network services connect in series across devices within the network, called service chaining. In this thesis, we formulate the problem of deterministic delay guarantee in service chaining. With the objective of providing deterministic delay guarantee in service chaining, we an- alyze the deterministic delay of the controller and VM-based network services. We model this service chain creation as a constrained shortest path problem (CSP), and propose a network calculus-based delay-guaranteed dynamic service chaining (NDDSC) mechanism. By using a centralized controller in an software-defined network (SDN), we implement the proposed mechanism. Our results show that NC-based dynamic service chaining mechanism can reconfigure the service chaining path for different network topologies and burst traffics subject to the deterministic constraints of users delay requirements.