J.K. MANDAL. Dean, Faculty of Engineering, Technology & Management Professor, Department of Computer Science & Engineering University of Kalyani

Transcription

1 J.K. MANDAL Dean, Faculty of Engineering, Technology & Management Professor, Department of Computer Science & Engineering University of Kalyani Kalyani, Nadia, West Bengal Mobile: /2/2011 com 1

2 T C P / I P C O M P O N E N T S TCP/IP was architected machine independent and is a client/server technology at the application layer. A client initiates (invokes) an application, and servers serve the requests of clients. Because of TCP/IP's design, TELNET (the application for remote logons) has a client and server, just as FIP (the application used for file transfers) and SMTP (the application used for E- Mail). Notice figure 3.1 where TELNET, FIP, SMTP, and other services reside at the application level 2

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4 Other application layer components exist. X is a protocol and provides a distributed window environment. It permits request responses between X client applications and an X server. X includes the ability of an X client executing on one machine to operate against an X server on another machine thus enabling a distributed windowing environment. Some X basic components include: X Server- A program providing display services on a terminal supporting graphics at the request of an X client application. XClient-Aprogramusingthe services provided by an X Server. 4

5 X Window Manager-This program helps in resizing windows, modifying windows, and relocating windows. X Library-This contains the interface for application programming. It consists of C language subroutines. One functionofthexlibistoconvert X client requests into X protocol requests. X Toolkits-This is a software library providing high level facilities for implementing buttons, menus, etc. Widgets-AwidgetisanXwindow, additional data, and procedures used to perform operations on that data. 5

6 Kerberos is a security protocol used with TCP/IP and operates by an authentication server, and by a "ticket" granting server. For example, a client requests a "ticket" to meet. the "ticket" granting server, thus achieving authentication. Once authentication is achieved the "ticket" is presented to the "ticket" granting server giving the client the ability to use a particular service. Common Information Management Service (CMIS) is a management service offered by the Common Management Information Protocol (CMIP). CMIP is an OSI method of network management. When CMIP management functions are mapped to the TCP/IP suite of protocols it is called Common Information Management Service over TCP/IP (CMOT). When it is mapped to the TCP/IP protocol suite it uses TCP for a transport connection. Figure 1 illustrates how CMIP operates over TCP. CMIP uses Abstract Syntax Notation 1 (ASN.1), a language defined by Internet standard documents. ASN.1 is a language for writing clear and uniform data type definitions used in the management function. 6

7 Simple Network Management Protocol (SNMP) uses UDP (to be discussed in greater detail later) for a transport mechanism. It uses "traps" to report events including variables pertaining to the status of a host and "agents" that are processes in a host which get and set specific requests and additionally send trap messages. As of this writing, SNMP is very popular for TCP/IP management. Remote Procedure Calls (RPCs) are programs permitting applications to call a routine executing a server; in turn the server returns variables and return codes to the requester. Simply, it is a mechanism implemented to support distributed computing via a client/server model. Network File Server (NFS) is a collection of protocols produced by SUN Microsystems and uses a distributed file system allowing multiple computers supporting NFS to access each other's directories transparently. 7

8 Trivial File Transfer Protocol (TFTP) uses UDP; it has no security such as FTP that utilizes TCP as a transport mechanism. It is a very simple means of file transfer and not robust when compared to FTP. Domain Name Service, also called the Domain Name System (DNS), is a distributed database system of IP addresses and aliases. It resolves addresses of hosts in order to establish contact with the target host. DNS was 'created to solve the problem of maintaining a host file on each host participating in' a TCP/IP network. The host file consists of IP addresses and aliases, and each time a host or network is added or taken away the host file would need changing. DNS was designed to forego the constant updating of each host file on every host. 8

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