The Design Of IP Network QoS Policy Management Tool Based On DiffServ Technology

With the development of network and IP technology, the service providers around the world deliver various new IP based services. This is transforming IP network from pure data transferring network into a multimedia network that is capable of transferring data, voice, still and moving images. However, the existing IP network provides best-effort service and can not guarantee Quality of Service (QoS) demanded by multimedia services. How to guarantee the QoS for real time multimedia services and implement QoS infrastructure on IP network have become a worldwide research focal point. Internet Engineering Task Force (IETF) developed models of Integrated Services (InterServ), Differentiated Services (DiffServ) and Multiprotocol Label Switching (MPLS). Though greatly advanced IPQos technology, these results are not the total solution of resolving QoS issues for the whole Internet. The infrastructure of QoS for the whole Internet is still lacking. In order to implement IPQoS, Policy-based Network Management (PBNM) has been developed to address QoS management issues. PBNM reaches the goal of managing network QoS by fulfilling a series of behaviors that manages policies. The IETF Policy Framework Working Group and the Distributed Management Working Group co-developed Policy Core Information Model (PCIM), an object oriented information model for policy information. Policy is a set of rules that define the required behavior or expected status of the system. Policy based network management reaches the goal of managing network QoS by fulfilling a series of behaviors that manages policies. The rules are used for managing and controlling network resources. Policy integrates high level business requirements with low level network devices. The language representing Policy is user friendly, which makes the network administrators able to use it to define policies that are both flexible and easy understood. A policy expresses business objectives, thus needs to be translated into specific network implementations. Business objectives can be described by Service Level Agreement (SLA) or Service Level Objectives (SLOs). SLA is usually written in high level business terms, and the high level description of network services and measures have to be translated into low level rules that are provider and device independent. The classes defined in PCIM serve as basis of these rules. PCIM defines a common model for policies, which can be used for QoS or non QoS like DHCP and IPSec, or even for non network applications like back strategy . IETF published an extension of Policy Core Information Model Extensions (PCIMe) and Policy Quality of Service (QoS) Information Model (PQIM) as RFC document in 2003. This document defined the properties, values, conditions and actions used by QoS management for both InterServ and DiffServ. Policy framework is mainly consisted of Policy Decision Point (PDP) and Policy Enforcement Point (PEP), where PEP locates inside network nodes and carries out execution of policy decisions, while PDP normally resides on policy servers and acts as a remote object to make policy decisions. PDP uses directory servers or relation database for query and store policy information. Directory servers are usually based on Lightweight Directory Access Protocol (LDAP). It uses a hierarchical structure, and can fulfill the requirement of hierarchical organization, schema recognition, type and object definition, permission control and authentication tree copy. LDAP has the advantage over relational database on data query speed, which makes it more suitable as policy servers. It is concluded that on the basis of these researches the IP network QoS management based on DiffServ technology is an efficient means of implementing network QoS management. The focus of this thesis is the study of design of DiffServ based IP network QoS policy management tool. The basic approach is to integrate policy based network management and DiffServ. Based on the classification of IPQoS by the International Standard Organization (ISO), user's requirements are translated into policies according to the SLA between the user and its service provider. The policies are stored in the policy servers which support PDP to provide results for queries submitted by PEP. This thesis analyzes the related standards and protocols in detail. Combining the technologies of SLA, SLS, DiffServ and PBNM, it designs the architect and the Policy Management Tool (PMT) Program for IP network QoS management system based on DiffServ technology. In addition, it establishes and analyzes an end-to-end design model, where the policy management program designed in this thesis is put into application. In order to translate the content of SLA protocol into the properties, values, conditions and actions that can be interpreted by the policy information model, this thesis emphasizes the analysis of IPQoS classification in ITU Y. 1541 according to the related RFC documents and ISO category classifications for IPQoS, and designs SLS parameters in detail. The requirements of QoS in SLA are translated into the DSCP levels defined by DiffServ technology, thus policy is formed, which enables the user to correlate the choices of various network QoS and the content in SLA with the policy information model. The representation of the policy is discussed, and the methodology of storing policy in the directory server is also devised. The method used by DiffServ model is to classify data flows at the edges of the networks. Different DS code is set in the IP header for the group before injecting into the network. The core routers that are responsible for resending the packets examine the DC code in the header of the group and identify the level of the service, then decide how to handle the packet. The main functionality of DiffServ is flow control and Per Hop behavior (PHB) based resend. IP network QoS Policy Management Tool Programs based on DiffServ technology is designed and implemented. The Policy Management Tool Program uses VB .net language. VB .net is an object oriented language supports all features needed by OOP programming, and it is a full-fledged programming language. Database uses iPlanet Directory Server by SunMicrosystems. The fact of Policy Management Tool Program being far less often storing entries than querying entries is to the advantage of improving network performance. The Policy Configuration Program in Policy Management Tool Program is for the purpose of configuring user's network QoS policies, while the Query Program in Policy Management Tool Program is for querying the policies in the policy information database. The Policy Configuration Program utilizes an user friendly GUI for customer's self-service of configuring the QoS requirements; Upon running, it creates visualized parameters for users to choice; based on user's choices, the management system then converts these parameters into policies that can be understood by the network, and stores the policies as entries in the directory server. Intelligent translation of IPQoS service policy from SLS is implemented, and storing and modification of user's network QoS information in the directory server are realized. The configurable parameters include: Service Zone, Service Time and Service Requirement. It is possible to choose guaranteed services under Reserved Services. After setting the parameters, choose Start in Start Services menu to make the choices become effective. The network QoS defined is then stored in the policy server. The Query Program in Policy Management Tool Program is used for query user's policies of the network QoS. When the network needs to query network QoS or when the network administrator needs to enquire user's network service policies, Query Program can be used to query. Upon the user inputs the policy code used when signing the application of network service SLA and password, the system retrieves the related policies and display them in the form of menu. Overall, IP network QoS policy management system based on DiffServ technology proves to be an efficient way of managing the quality of service for the network. The Policy Management Tool Program is capable of storing and querying policies, and the directory server is suitable serving as the policy server.