Functional Architectures - Network Communication - Lecture Slides, Slides of Data Communication Systems and Computer Networks

Download Functional Architectures - Network Communication - Lecture Slides and more Slides Data Communication Systems and Computer Networks in PDF only on Docsity! Major Network Functional Architectures (® docsity.com Chapter Objectives •Discuss the characteristics, features etc of Peer-to- peer and client-server networks •Discuss the emerging concept of thin-clients •Examine the network operating system in terms of the client and sever components •Provide an overview of the desirable characteristics of the server and client hardware docsity.com MODULE Peer-to-Peer Network Architecture docsity.com Questions •What are the characterizing features of peer-to- peer architecture? •Name some application areas of peer-to-peer architecture? •What are the two different types of access controls that could be imposed on peer-to-peer networks? Focus on the networks that could be set up with Windows 9x and the Windows 2000 or the Windows XP Client operating systems? docsity.com Peer-to-Peer Configuration WorkstationWorkstation Printer • Share and share alike among peer stations • Absence of a server docsity.com Peer-to-Peer Implementation • Any number of computers can be connected as long as they are not used for multi-user applications • An example of a multi-user application is the SQL database application • Limiting factor • Narrow scope of directory implementation and peripheral sharing docsity.com Peer-to-Peer Sharing • Simple sharing of resources • Share • Files • Printers • Sharing an Internet connection • etc. • Simple messaging • Unsuitable for multi-user business applications • Limited number of connections and limited sharing docsity.com Windows XP Professional • File and printer sharing • A web server could also be run on an XP client • However, the connection is limited to only 10 concurrent users docsity.com Printer (Password) Typical Peer-to-Peer Security Folder (Password) Network Workstation (Name) docsity.com Peer-to-Peer Security • No administrator to administer the overall security of the network resources • Resources are independently administered by the user on each peer computer (client) • No centralized control on the resources docsity.com Operating Systems Supporting Peer-to-Peer Networking • Nearly all the client operating systems of today support peer-to-peer networking docsity.com Peer-to-Peer Networks Based on Windows 9x •Only share level access control is possible • Access to a resource such as a printer, for example, can be controlled based on passwords only and not based on user names •User level access control is not possible where access to the resources could be controlled based on user names • Each user may be given a different type of access to the resource docsity.com A Note on Windows NT, Windows 2000 and Windows XP • It is possible to configure peer-to-peer networks with Windows NT Workstation, Windows 2000 Professional, Windows XP Professional, and Windows 7 •Such networks offer better security compared to the same configured with Windows 95/98 •User-level access control is enforced in this case docsity.com File Systems • Windows • FAT32 • NTFS 5.0 • Linux • .ext2 • Mac OS • HFS – older version • HFS+ - Later version docsity.com v END OF MODULE docsity.com MODULE Client-Server Network Architecture docsity.com A Typical Client-Server Physical Architecture Client Client Server Printer Note: This is simply a physical client-server architecture. File Server Application Server Thin-client Server docsity.com Client-Server Network Architecture and Applications •The presence of a client-server physical network architecture does not necessarily imply that client- server applications are running on the network •Distinguishing between client-server physical network architecture and client-server applications is important •A client-server network physical architecture is required to support client-server applications docsity.com Client-Server Access Control • Possible to exercise control at the user level • Access control can be imposed based on user names • Different levels of access can be given to different users • Read and Write • Read Only etc. docsity.com Client Server Access Control On a Folder Server Client Client Tariff User1 R & W User2 R User1 User2 User3 docsity.com Client-Server Network Application Architecture • File Server • Application server • Thin-Client docsity.com Functional Architectures Peer-to-Peer Client-Server File Server Application Server Thin-Client Functional Architectures Share- Level Access Control User Level Access Control docsity.com Physical and Application Architectures Client Client Server Printer File Server Application Server Thin-client Server docsity.com MODULE File Server Networks docsity.com File Server and Application Servers • File server is the simplest architecture • Application server is the more advanced architecture • Forms the core of the implementation of the client server technology • Thin-client is also an advanced architecture docsity.com Questions to be Asked • Place of execution for application • Network traffic implications • TCO • Enforcing security • Software requirements • Server side • Client side docsity.com File Server in a Nut Shell •The file server basically operates as one large shared storage space for the clients •Any client with the permission to access the resources on the file server can share folders etc. on the file server • In effect, the file server functions as a logical disk (network drive) as far as the client is concerned • Compared to a local disk, the difference is that the logical disk can be shared by other clients as well docsity.com The Logical Drive Concept Physical Drive c: Logical or Network Drive f: Logical drive is physically located at the server. Client Station Physically present on the client Shared storage from the server docsity.com File Server Characteristics •Shared data is stored on the server and brought to the client for processing •Shared application software are also stored on the server •Entire execution takes place at the client •Consequently, considerable network traffic is generated as the files are ported to the client for processing • Application server networks overcome this drawback by executing part of the application on the server docsity.com v END OF MODULE docsity.com MODULE Application Servers and the Client-Server Technology docsity.com A Note • Presence of a physical client-server network architecture does not necessarily imply the presence of applications running based on the client-server technology docsity.com Software Examples of the Components of Client- Server Technology • Database engine • Microsoft SQL server • Front-end tool • Microsoft Office suite docsity.com Client Network Traffic in Application Server Networks Server Database data Retrieved Data Request for data, not for the entire file Requested data only Retrieved data can be processed by an front end tool such as Excel docsity.com Advantages of Client-Server Technology • Reduction in network traffic • Only the requested data and not the entire data file is transmitted over the network • Data can be better administered and controlled • Located on a centralized server and processed on the server itself docsity.com v END OF MODULE docsity.com MODULE Terminal Server and the Thin-Client Concept docsity.com A Note • Terminal server is not synonymous with thin-client • Microsoft’s implementation is terminal server • There are other implementations of the thin-client concept as well • Sun Microsystems implementation (Network Computer ??? Java Machine ??) docsity.com Network Computer • Proposed by Oracle and Sun • No CD-ROM players, diskette drives, and expansion slots, • Managed centrally • Likely to be based on a non-Intel microprocessor • Unlike Windows, this may be based on a Java based operating system docsity.com Terminal Server and Remote Execution Software • PCAnywhere • This is not a terminal server application • It is a remote execution software docsity.com Thin-Client Architecture • Presence of a thin-client server is often required • A server that supports the thin-client architecture docsity.com Web Research •Explain the features of the following two thin client implementations • Network Computer • NetPC •Visit www.compaq.com and obtain information about Compaq’s thin client offerings •Visit www.citrix.com and obtain an exploratory information on Citrix’s implementation of thin- clients also know as Metaframe docsity.com Key Words • Embedded OS • Application Service Providers • Virtual Private Network docsity.com Multiple Architectural Configurations NFS File Server SQL Database Engine Unix Machine File Server Application Server Terminal Server docsity.com Basis for Client-Server Technology • Client-server networks • Application servers • Information storage and retrieval is at the server • Manipulation of the retrieved information is at the client docsity.com Client-Server Advantages • Centralized administration and control • Better security • Powerful network operating system • Support for Internet and Intranet docsity.com Client-Server Scope • Large number of users • As per network OS License • Large number of servers and clients • Larger networks can be supported • Clustering and linking or workstations docsity.com v END OF MODULE docsity.com MODULE Server and Client Hardware docsity.com Server Hardware • Powerful hardware should be used • Because it is engaged in multitasking • Largely limited by the scale of economy • Hardware changes rapidly • It is not possible to give specific examples as to the exact type hardware that should be used docsity.com Guideline for Server: Storage •Require storage in Gigabytes •Use a faster and better storage technology • ATA/66,100,133 • Serial ATA • SCSI 1, 2 and 3 • SCSI 3 operates at 160M Bytes per second •Cutting edge of storage technology • Fiber channel storage docsity.com RAID Storage • Multiple disk arrays for fault tolerance docsity.com Storage Area Network (SAN) • Storage Area Network • Built on fiber channel docsity.com A Guideline for Choosing Client Hardware • Largely determined by the client operating system and the network applications •Example: Windows XP, Windows Vista • Choose the hardware to satisfy Windows XP requirements on a single desktop •Exception is a thin client • Network PC • Network Computer based on a Java oriented network architecture docsity.com Microsoft-Intel Hardware Specifications • Released on a yearly basis • Combined effort between Microsoft and Intel • Sample specifications for a particular year • Access Microsoft’s website docsity.com Web Research • Visit a server vendor such as www.compaq.com and obtain the special features of a server • RAID storage • Hot-swappable components • I/O technology • UPS docsity.com MODULE Practical Network Operating Systems docsity.com Overview of Operating Systems in a Network • Basic network operating system • Windows 2008 • Windows 2003 Server R2 • Windows 2003 Server • Windows 2000 Server • Windows NT Server • Mac OS • Linux • Client operating system • Windows Vista, Windows XP, Windows 2000 Professional, Windows ME, Windows 95/98, Windows NT Workstation, Linux etc. docsity.com Examples of Basic Network Operating System •Windows 2008 • Replacement for Windows 2003 Server •Windows 2003 Server • Replacement for Windows 2000 Server •Windows 2000 Server • Successor to Windows NT docsity.com