Delivery The network layer supervises the handling of the packets by the underlying physical networks. We define this handling as the delivery of a packet. The delivery of a packet to its final destination is accomplished using two different methods of delivery: direct and indirect. Direct Delivery In a direct delivery, the final destination of
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As we discussed before, the IP addresses were originally designed with two levels of addressing. To reach a host on the Internet, we must first reach the network and then the host. It soon became clear that we need more than two hierarchical levels, for two reasons. First, an organization that was granted a block
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Two level addressing : The whole purpose of IPv4 addressing is to define a destination for an Internet packet (at the network layer). When classful addressing was designed, it was assumed that the whole Internet is divided into many networks and each network connects many hosts. In other words, the Internet was seen as a
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The network layer is designed as a packet switched network. This means that the packet at the source is divided into manageable packets, normally called datagrams. Individual datagrams are then transferred from the source to the destination. The received datagrams are assembled at the destination before recreating the original message. The packet-switched network layer of
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Wireless communication is one of the fastest-growing technologies. The demand for connecting devices without the use of cables is increasing everywhere. Wireless LANs can be found on college campuses, in office buildings, and in many public areas. In this section, we concentrate on two wireless technologies for LANs: IEEE 802.11 wireless LANs, sometimes called wireless
In this section we briefly describe the functions of each layer in the OSI model. Physical Layer The physical layer coordinates the functions required to carry a bit stream over a physical medium. It deals with the mechanical and electrical specifications of the interface and transmission media. It also defines the procedures and functions that
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Established in 1947, the International Standards Organization (ISO) is a multinational body dedicated to worldwide agreement on international standards. Almost three-fourths of countries in the world are represented in the ISO. An ISO standard that covers all aspects of network communications is the Open System Interconnection (OSI) model. It was first introduced in the late
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Cerf and Kahn’s landmark 1973 paper outlined the protocols to achieve end-to-end delivery of data. This was a new version of NCP. This paper on transmission control protocol (TCP) included concepts such as encapsulation, the datagram, and the functions of a gateway. A radical idea was the transfer of responsibility for error correction from the
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Terminology in Computer Networking AIMD – Additive Increase, Multiplicative Decrease. A rate adaption algorithm used notably by TCP where a host additively increases its transmission rate when the network is not congested and multiplicatively decreases when congested is detected. anycast – a transmission mode where an information is sent from one source to one receiver
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Many point-to-point datalink layers have been developed, starting in the 1960s. In this section, we focus on the protocol that are often used to transport IP packets between hosts or routers that are directly connected by a point-to-point link. This link can be a dedicated physical cable, a leased line through the telephone network or
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