June 2022

The Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) Medium Access Control algorithm was designed for the popular WiFi wireless network technology. CSMA/CA also senses the transmission channel before transmitting a frame. Furthermore, CSMA/CA tries to avoid collisions by carefully tuning the timers used by CSMA/CA devices. CSMA/CA uses acknowledgements like CSMA. Each frame contains

Carrier Sense Multiple Access (CSMA) improves channel utilization compared to ALOHA. However, the performance can still be improved, especially in wired networks. Consider the situation of two terminals that are connected to the same cable. This cable could, for example, be a coaxial cable as in the early days of Ethernet [Metcalfe1976]. It could also

In a large IP network such as the global Internet, routers need to exchange routing information. The Internet is an interconnection of networks, often called domains, that are under different responsibilities. As of this writing, the Internet is composed on more than 30,000 different domains and this number is still growing. A domain can be

As mentioned in the first section of this chapter, there are three main types of datalink layers : point-to-point links, LANs supporting broadcast and multicast and NBMA networks. There are two important issues to be addressed when using IPv4 in these types of networks. The first issue is how an IPv4 device obtains its IPv4

There are two possible internal organisation of the network layer : Datagram Virtual circuits The internal organisation of the network is orthogonal to the service that it provides, but most of the time a datagram organisation is used to provide a connectionless service while a virtual circuit organisation is used in networks that provide a

The Transmission Control Protocol (TCP) was initially defined in RFC 793. Several parts of the protocol have been improved since the publication of the original protocol specification. However, the basics of the protocol remain and an implementation that only supports RFC 793 should inter-operate with today’s implementation. TCP provides a reliable bytestream, connection-oriented transport service

The User Datagram Protocol (UDP) is defined in RFC 768. It provides an unreliable connectionless transport service on top of the unreliable network layer connectionless service. The main characteristics of the UDP service are : The UDP service cannot deliver SDUs that are larger than 65507 bytes The UDP service does not guarantee the delivery

The transport layer entity interacts with both a user in the application layer and an entity in the network layer. According to the reference model, these interactions will be performed using DATA.req and DATA.ind primitives. However, to simplify the presentation and to avoid confusion between a DATA.req primitive issued by the user of the transport