Vincicore Munna. Hassan alla. Rooparam Choudhary. Radhika Raghav. More From Hemant Mohite. Hemant Mohite. Computer Organization and Architecture - Shrivastava - Ibrg.
Raghavendra Prasad Reddy. Tetuan Azlan. Ravi Teja Sikhakolli. Popular in Baseband. Jonnel Rzykruski. Jamie Taylor. Toure Moussa. Lysa Dee. Umer farooq. Idowu Ojo. Engr aqib. Endah Fitriani. Supipi Hiyadma. Javier Mejia. Mohammed Alqadasi. Khalid Mahmud. Tafadzwa Comfort Nyambira. Manju Chavan. Anonymous jxm0WNS7Qa. Pavan Chavariya. Duplication of resources meant that the same hardware and software had to be supplied to each office or department, as did separate support staff.
This lack of network management meant that no centralized method of managing and troubleshooting networks existed. Book Description Internetworking refers to the industry, products, and procedures that meet the challenge of creating and administering internetworks. Previous Post: « Go It Alone! The IP addresses are used by the internetwork and higher layers to identify devices and to perform internetwork routing.
IP is a connectionless protocol , which means that IP does not exchange control information called a handshake to establish an end-to-end connection before transmitting data. In contrast, a connection-oriented protocol exchanges control information with the remote computer to verify that it is ready to receive data before sending it.
When the handshaking is successful, the computers are said to have established a connection. IP relies on protocols in other layers to establish the connection if connection-oriented services are required. IP also relies on protocols in another layer to provide error detection and error recovery.
Because it contains no error detection or recovery code, IP is sometimes called an unreliable protocol. Define the datagram, which is the basic unit of transmission in the Internet. A packet is a block of data that carries with it the information necessary to deliver it--in a manner similar to a postal letter that has an address written on its envelope.
A packet switching network uses the addressing information in the packets to switch packets from one physical network to another, moving them toward their final destination. Each packet travels the network independently of any other packet. The datagram is the packet format defined by IP. Define the Internet addressing scheme. IP delivers the datagram by checking the destination address in the header.
If the destination address is the address of a host on the directly attached network, the packet is delivered directly to the destination. If the destination address is not on the local network, the packet is passed to a gateway for delivery. Gateways and routers are devices that switch packets between the different physical networks. Deciding which gateway to use is called routing. IP makes the routing decision for each individual packet. When IP receives a datagram that is addressed to the local host, it must pass the data portion of the datagram to the correct host-to-host transport layer protocol.
This selection is done by using the protocol number in the datagram header. Each host-to-host transport layer protocol has a unique protocol number that identifies it to IP.
Route datagrams to remote hosts. Internet gateways are commonly and perhaps more accurately referred to as IP routers because they use IP to route packets between networks. Gateways forward packets between networks and hosts do not. However, if a host is connected to more than one network called a multi-homed host , it can forward packets between the networks. When a multi-homed host forwards packets, it acts like any other gateway and is considered to be a gateway.
Fragment and reassemble datagrams. As a datagram is routed through different networks, it may be necessary for the IP module in a gateway to divide the datagram into smaller pieces. A datagram received from one network may be too large to be transmitted in a single packet on a different network. This condition only occurs when a gateway interconnects dissimilar physical networks. Flow control. When datagrams arrive too quickly for processing, the destination host or an intermediate gateway sends an ICMP source quench message back to the sender.
This message instructs the source to stop sending datagrams temporarily. Detect unreachable destinations. When a destination is unreachable, the computer detecting the problem sends a destination unreachable message to the datagram's source.
If the unreachable destination is a network or host, the message is sent by an intermediate gateway. But if the destination is an unreachable port, the destination host sends the message. Redirect routes. A gateway sends the ICMP redirect message to tell a host to use another gateway, presumably because the other gateway is a better choice.
This message can only be used when the source host is on the same network as both gateways. Check remote hosts. When a computer receives an echo message, it sends the same packet back to the source host. The protocol layer just above the internetwork layer is the host-to-host layer. It is responsible for end-to-end data integrity. TCP provides reliable, full-duplex connections and reliable service by ensuring that data is resubmitted when transmission results in an error end-to-end error detection and correction.
Also, TCP enables hosts to maintain multiple, simultaneous connections. When error correction is not required, UDP provides unreliable datagram service connectionless that enhances network throughput at the host-to-host transport layer.
Both protocols deliver data between the application layer and the internetwork layer. Applications programmers can choose the service that is most appropriate for their specific applications. The User Datagram Protocol gives application programs direct access to a datagram delivery service, like the delivery service that IP provides. This direct access allows applications to exchange messages over the network with a minimum of protocol overhead.
UDP is an unreliable, connectionless datagram protocol. Within your computer, UDP will deliver data correctly. Why do applications programmers choose UDP as a data transport service? A number of good reasons exist. If the amount of data being transmitted is small, the overhead of creating connections and ensuring reliable delivery may be greater than the work of retransmitting the entire data set.
In this case, UDP is the most efficient choice for a host-to-host transport layer protocol. Applications that fit a "query-response" model are also excellent candidates for using UDP. The response can be used as a positive acknowledgment to the query. If a response is not received within a certain time period, the application just sends another query.
Still other applications provide their own techniques for reliable data delivery and do not require that service from the transport layer protocol.
Imposing another layer of acknowledgment on any of these types of applications is redundant. Applications that require the host-to-host transport protocol to provide reliable data delivery use TCP because it verifies that data is delivered across the network accurately and in the proper sequence. TCP is a reliable, connection-oriented, byte-stream protocol. Performs basic interactive file transfers between hosts.
0コメント