Computer Network Articles - Page 110 of 122

Synchronous optical networking (SONET) is a physical layer protocol for transmitting multiple digital bit streams over optical fiber links that form the backbone of the communication networks. Packet-over-SONET (POS) is a standard that maps IP packets into SONET frames. To implement this mechanism, Point – to – Point Protocol (PPP) runs on IP routers. Point – to – Point Protocol (PPP) is a data link layer protocol that is used to transmit data between two directly connected (point-to-point) computers. It is a byte-oriented protocol that is widely used in broadband communications having heavy loads and high speeds.The following diagram shows ... Read More

In data communications, when a receiver receives a message, it sends an acknowledgement back to the sender to notify it about correct receipt of the message. Cumulative acknowledgement is a process in which the receiver sends a single acknowledgement in response to a finite number of frames received. Through this, the receiver acknowledges that it has correctly received all previous frames or packets. When the sender receives an acknowledgement for frame n, it understands correct delivery of frames n – 1, n – 2 and so on.Cumulative acknowledgement is used along with sliding window protocols. It reduces the time and ... Read More

Dynamic channel allocation are schemes for allotting shared network channels to competing users in a dynamic manner as per their requirements. The users may be base stations, access points or terminal equipment which are allotted channels from a central pool. There are a number of methods for dynamic channel allocation. The key assumptions of these methods are −Independent Traffic − It is assumed that the users are independent of each other, i.e. each user has to send or receive data which is independent of the data transmission of the other users in the network system. Each user has a program ... Read More

The medium access control (MAC) is a sublayer of the data link layer of the open system interconnections (OSI) reference model for data transmission. It is responsible for flow control and multiplexing for transmission medium. It controls the transmission of data packets via remotely shared channels. It sends data over the network interface card. MAC Layer in the OSI Model The Open System Interconnections (OSI) model is a layered networking framework that conceptualizes how communications should be done between heterogeneous systems. The data link layer is the second lowest layer. It is divided into two sublayers − ... Read More

PPP over ATM (PPPoA) is a data link layer protocol to transmit PPP data over ATM networks, by encapsulating PPP frames in ATM Adaptation Layer 5 (AAL 5) frames.Point − to − Point Protocol (PPP) is a data link layer protocol that is used to transmit data between two directly connected (point-to-point) computers. It is a byte – oriented protocol that is widely used in broadband communications having heavy loads and high speeds. It is also known as RFC 1661.In Asynchronous Transfer Mode (ATM) networks, the ATM Adaptation Layer (AAL) provides facilities for non-ATM based networks to connect to ATM ... Read More

In Asynchronous Transfer Mode (ATM) networks, the ATM Adaptation Layer (AAL) provides facilities for non-ATM based networks to connect to ATM network and use its services.AAL is basically a software layer that accepts user data, which may be digitized voice, video or computer data, and makes them suitable for transmission over an ATM network. The transmissions can be of fixed or variable data rate. AAL accepts higher layer packets and segments them into fixed sized ATM cells before transmission via ATM. It also reassembles the received segments to the higher layer packets.The following diagram illustrates the function of AAL −This ... Read More

Virtual Circuit Identifier (VCID or VCI) is an identifier or label on any virtual circuit in a computer network that indicates where a data unit has to travel over the network.A virtual circuit (VC) is a technique by which data is transmitted over a packet switched network such that it seems as though there is a dedicated physical link between the source and destination systems.VCID allows the same channel to be used for simultaneous connections. The same VCID may be reused by connections having disjoint paths, allowing the network to support concurrent connections.Establishment of VC and use of VCIDThe following ... Read More

Asymmetric Digital Subscriber Line (ADSL) is a type of broadband communications technology that transmits digital data at a high bandwidth over existing phone lines to homes and businesses.ADSL protocol stack depicts the set of protocols and devices that are used along with ADSL.In order to access ADSL, a Digital Subscriber Line modem (DSL modem) is installed at the customer site. The DSL modem sends data bits over the local loop of the telephone network. The local loop is a two − wire connection between the subscriber’s house and the end office of the telephone company. The data bits are accepted ... Read More

Asymmetric Digital Subscriber Line (ADSL) is a type of broadband communications technology that transmits digital data at a high bandwidth over existing phone lines to homes and businesses.In order to access ADSL, a Digital Subscriber Line modem (DSL modem) is installed at the client side. The DSL modem sends data bits over the local loop of the telephone network. The local loop is a two – wire connection between the subscriber’s house and the end office of the telephone company. The data bits are accepted at the end office by a device called Digital Subscriber Line Access Multiplexer (DSLAM).Features of ... Read More

In computer networking and telecommunications, when a transmission unit is sent from the source to the destination, it contains both a header and the actual data to be transmitted. This actual data is called the payload. The header contains the protocol information as well as the source and destination addresses, which are required for delivery of the payload. The payload is required by the destination client.The following diagram depicts encapsulation of payload field in a data link layer frame. The data packet from the upper layer is framed by adding a header that contains the control information for data transmission, ... Read More