Basics of Computer Networking

by Dinesh Thakur Category: Network Technologies

• Session Initiation Protocol (SIP) was designed by IETF and is described in RFC 3261.

 
by Dinesh Thakur Category: Network Technologies
1. TDM is the digital multiplexing technique.
2. In TDM, the channel/link is not divided on the basis of frequency but on the basis of time.
3. Total time available in the channel is divided between several users.
4. Each user is allotted a particular a time interval called time slot or time slice during which the data is transmitted by that user.
5. Thus each sending device takes control of entire bandwidth of the channel for fixed amount of time.
 
by Dinesh Thakur Category: Network Technologies

ISDN structure includes a central ISDN office. All the users are linked to this office through a digital pipe. This digital pipe may be of different capacities and may have different data transfer rates. These digital pipes between the customers and central office are organized into multiple channels of different size.

 
by Dinesh Thakur Category: Network Technologies

The ISDN technology (Integrated Services Digital Network, or ISDN) means complete digitization so that all communication established in digital form, providing a wide range of services.

Integrated Services Digital Network is a telephone system network. It is a wide area network becoming widely available. Prior to the ISDN, the phone system was viewed as a way to transport voice, with some special services available for data. The key feature of the ISDN is that it integrates speech and data on the same lines, adding features that were not available in the classic telephone system.

 
by Dinesh Thakur Category: Network Technologies

The Token-Passing Protocol relies on a control signal called the token. A token is a 24-bit packet that circulates throughout the network from NIC to NIC in an orderly fashion. If a workstation wants to transmit a message, first it must seize the token. At that point, the workstation has complete control over the communications channel. The existence of only one token eliminates the possibility of signal collisions. This means that only one station can speak at a time.

 
by Dinesh Thakur Category: Network Technologies

A communications device that multiplexes (combines) several signals for transmission over a single medium. A demultiplexer completes the process by separating multiplexed signals from a transmission line. Frequently a multiplexer and demultiplexer are combined into a single device capable of processing both outgoing and incoming signals. A multiplexer is sometimes called a mux.

 
by Dinesh Thakur Category: Network Technologies

In Computer network, a proxy server is a server (a computer system or an application program) that acts as an intermediary for requests from clients seeking resources from other servers. A client connects to the proxy server, requesting some service, such as a file, connection, web page, or other resource, available from a different server.



 
by Dinesh Thakur Category: Network Technologies

Divides Application Processing across multiple machines.Non-critical data and functions are processed on the client Critical functions are processed on the server

 
by Dinesh Thakur Category: Network Technologies

Client/Server Architecture The client/server architecture significantly decreased network traffic by providing a query response rather than total file transfer. It allows multi-user updating through a GUI front end to a shared database. Remote Procedure Calls (RPCs) or standard query language (SQL) statements are typically used to communicate between the client and server.



 
by Dinesh Thakur Category: Network Technologies

A server process (program) fulfills the client request by performing the task requested. Server programs generally receive requests from client programs, execute database retrieval and updates, manage data integrity and dispatch responses to client requests.



 
by Dinesh Thakur Category: Network Technologies

The client is a process that sends a message to a server process requesting that the server perform a task. Client programs usually manage the user-interface portion of the application, validate data entered by the user, dispatch requests to server programs, and sometimes execute business logic.

 
by Dinesh Thakur Category: Network Technologies

Server: A server is a computer program or device in the network that provides resources, data, services, or programs to the client computer such as login requests processing, files access and storage, internet access, printing access and many other types of services. This architecture is called the client-server model. Servers are often referred to as dedicated.



 
by Dinesh Thakur Category: Network Technologies

Frequency-Division Multiplexing (FDM) is a scheme in which numerous signals are combined for transmission on a single communications line or channel. It is analog multiplexing technique. Each signal is assigned a different frequency (sub channel) within the main channel. its requires channel synchronization. FDM multiplexing technique is based on orthogonality of sinusoids.

 
by Dinesh Thakur Category: Multiple Access

The TCP / IP layer set corresponds to the OSI reference model levels as follows:

This correspondence is theoretical because, as the TCP / IP protocols developed before the OSI reference model, there are substantial differences, such as:



 
by Dinesh Thakur Category: Multiple Access

MIMO technology (Multiple Input Multiple Output) is not new, but it hits the market that at the end of the first decade of the 2000s due to a very complex implementation. MIMO aims to carry multiple streams in parallel on different antennas but using the same frequency.

 
by Dinesh Thakur Category: Multiple Access

Random Access, which is to issue a completely random time, relies on the Aloha method. The latter takes its name from an experiment performed on a network connecting the various islands of the Hawaiian Archipelago early 1970. In this method, when a coupler has information to transmit, it sends it without worry about other users. If there is a collision, that is to say superposition of two signals or more users, the signals become indecipherable and are lost. They are subsequently transmitted, as shown in Figure, in which the couplers 1, 2 and 3 collide. The coupler 1 transmits its field first because he shot the smallest timer. Then, the module 2 emits, and its signals collide with the coupler 1. Both derive a random time of retransmission. The coupler 3 is listening while the couplers 1 and 2 are silent, so that the frame of the coupler 3 passes successfully. Technical aloha is the origin of all the random access methods.



 
by Dinesh Thakur Category: Multiple Access

SONET/SDH standard was carry telephone speech, and it took many adaptations for the transport of frames and type of IP packets, ATM, or others. The successor of SONET/SDH has been launched in early 2002 and standardized by ITU-T as the OTN (Optical Transport Network). Its role is to channel packages on routes to 2,5, 10 and 40 Gbit/s. The corresponding recommendation G.709 carries the number.

 
by Dinesh Thakur Category: Multiple Access

SDH recommendation was standardized by ITU-T (G.707 and G.708):

• G.707: Synchronous Digital Bit Rate;

• G.708: Network Node Interface for the Synchronous Digital Hierarchy.

Found in SDH flows at 155, 622 and 2488 Mbit/s SONET.

 
by Dinesh Thakur Category: Multiple Access

To achieve simultaneous multiplexing multiple telephone lyrics on the same circuit, Americans have adopted a standard for multiplexing 24 channels of 64 kbit/s on a support at 1544 Kbit / s. This channel is called DS-1. Europeans have responded to this technique by the E-1 channel multiplexing 30 voice channels on a support 2048 Mbit/s. From this basic multiplexing, a hierarchy has been defined, it is a multiple of the base channel, as in the case of Europe, or a little more complex, as in the US case, because an area of supervision rate-dependent.

 
by Dinesh Thakur Category: Multiple Access

In the 1970s, the Department of Defense, or DOD (Department Of Defense), decided before the proliferation of machines using different, incompatible communication protocols, to define its own architecture. This architecture, called TCP / IP, is the source of the Internet. It is also adopted by many private networks, called intranets.



 

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About Dinesh Thakur

Dinesh ThakurDinesh Thakur holds an B.C.A, MCSE, MCDBA, CCNA, CCNP, A+, SCJP certifications. Dinesh authors the hugely popular blog. Where he writes how-to guides around Computer fundamental , computer software, Computer programming, and web apps. For any type of query or something that you think is missing, please feel free to Contact us.