SNS COLLEGE OF TECHNOLOGY

(Autonomous ) COIMBATORE-35 UNIT 1 TOKEN PASSING, CSMA/CD AND TCP/IP PROTOCOL

BY SHANGKAVI G, AP/EIE

TOKEN PASSING, CSMA/CD AND TCP/IP 1/29/2019 1/21 PROTOCOL TOKEN PASSING, CSMA/CD AND TCP/IP 1/29/2019 2/21 PROTOCOL TOKEN PASSING

• On a , token passing is a where a signal called a token is passed between nodes to authorize that node to communicate. In contrast to polling access methods, there is no pre-defined "master" node. • The most well-known examples are and ARCNET, but there were a range of others, including FDDI (Fiber Distributed Data Interface), which was popular in the early to mid 1990s.

TOKEN PASSING, CSMA/CD AND TCP/IP 1/29/2019 3/21 PROTOCOL • Token passing schemes degrade deterministically under load, which is a key reason why they were popular for industrial control LANs such as MAP, (Manufacturing Automation Protocol). • The advantage over contention based channel access (such as the CSMA/CD of early ), is that collisions are eliminated, and that the channel bandwidth can be fully utilized without idle time when demand is heavy. • The disadvantage is that even when demand is light, a station wishing to transmit must wait for the token, increasing latency.

TOKEN PASSING, CSMA/CD AND TCP/IP 1/29/2019 4/21 PROTOCOL • Some types of token passing schemes do not need to explicitly send a token between systems because the process of "passing the token" is implicit. • An example is the channel access method used during "Contention Free Time Slots" in the ITU-T G.hn standard for high-speed local area networking using existing home wires (power lines, phone lines and coaxial cable).

TOKEN PASSING, CSMA/CD AND TCP/IP 1/29/2019 5/21 PROTOCOL CSMA/CD

• Carrier-sense multiple access with collision detection • Carrier-sense multiple access with collision detection (CSMA/CD) is a media access control method used most notably in early Ethernet technology for local area networking. It uses carrier-sensing to defer transmissions until no other stations are transmitting.

TOKEN PASSING, CSMA/CD AND TCP/IP 1/29/2019 6/21 PROTOCOL • This is used in combination with collision detection in which a transmitting station detects collisions by sensing transmissions from other stations while it is transmitting a frame. • When this collision condition is detected, the station stops transmitting that frame, transmits a jam signal, and then waits for a random time interval before trying to resend the frame.

TOKEN PASSING, CSMA/CD AND TCP/IP 1/29/2019 7/21 PROTOCOL • CSMA/CD is a modification of pure carrier- sense multiple access (CSMA). CSMA/CD is used to improve CSMA performance by terminating transmission as soon as a collision is detected, thus shortening the time required before a retry can be attempted.

TOKEN PASSING, CSMA/CD AND TCP/IP 1/29/2019 8/21 PROTOCOL TCP/IP (Transmission Control Protocol/Internet Protocol)

• TCP/IP, or the Transmission Control Protocol/Internet Protocol, is a suite of communication protocols used to interconnect network devices on the internet. • TCP/IP can also be used as a communications protocol in a private network (an intranet or an extranet).

TOKEN PASSING, CSMA/CD AND TCP/IP 1/29/2019 9/21 PROTOCOL • The entire internet protocol suite -- a set of rules and procedures -- is commonly referred to as TCP/IP, though others are included in the suite. • TCP/IP specifies how data is exchanged over the internet by providing end-to-end communications that identify how it should be broken into packets, addressed, transmitted, routed and received at the destination. • TCP/IP requires little central management, and it is designed to make networks reliable, with the ability to recover automatically from the failure of any device on the network.

TOKEN PASSING, CSMA/CD AND TCP/IP 1/29/2019 10/21 PROTOCOL • The two main protocols in the internet protocol suite serve specific functions. TCP defines how applications can create channels of communication across a network. • It also manages how a message is assembled into smaller packets before they are then transmitted over the internet and reassembled in the right order at the destination address.

TOKEN PASSING, CSMA/CD AND TCP/IP 1/29/2019 11/21 PROTOCOL • IP defines how to address and route each packet to make sure it reaches the right destination. • Each gateway computer on the network checks this IP address to determine where to forward the message.

TOKEN PASSING, CSMA/CD AND TCP/IP 1/29/2019 12/21 PROTOCOL • The history of TCP/IP • The Defense Advanced Research Projects Agency (DARPA), the research branch of the U.S. Department of Defense, created the TCP/IP model in the 1970s for use in ARPANET, a wide area network that preceded the internet. • TCP/IP was originally designed for the Unix operating system, and it has been built into all of the operating systems that came after it. • The TCP/IP model and its related protocols are now maintained by the Internet Engineering Task Force.

TOKEN PASSING, CSMA/CD AND TCP/IP 1/29/2019 13/21 PROTOCOL How TCP/IP works

• TCP/IP uses the client/server model of communication in which a user or machine (a client) is provided a service (like sending a webpage) by another computer (a server) in the network. • Collectively, the TCP/IP suite of protocols is classified as stateless, which means each client request is considered new because it is unrelated to previous requests. Being stateless frees up network paths so they can be used continuously.

TOKEN PASSING, CSMA/CD AND TCP/IP 1/29/2019 14/21 PROTOCOL • The transport layer itself, however, is stateful. It transmits a single message, and its connection remains in place until all the packets in a message have been received and reassembled at the destination.

TOKEN PASSING, CSMA/CD AND TCP/IP 1/29/2019 15/21 PROTOCOL TOKEN PASSING, CSMA/CD AND TCP/IP 1/29/2019 16/21 PROTOCOL • The TCP/IP model differs slightly from the seven- layer Open Systems Interconnection (OSI) networking model designed after it, which defines how applications can communicate over a network. • TCP/IP model layers • TCP/IP functionality is divided into four layers, each of which include specific protocols.

TOKEN PASSING, CSMA/CD AND TCP/IP 1/29/2019 17/21 PROTOCOL • The application layer provides applications with standardized data exchange. Its protocols include the Hypertext Transfer Protocol (HTTP), File Transfer Protocol (FTP), Post Office Protocol 3 (POP3), Simple Mail Transfer Protocol (SMTP) and Simple Network Management Protocol (SNMP). • The transport layer is responsible for maintaining end-to-end communications across the network. TCP handles communications between hosts and provides flow control, multiplexing and reliability. The transport protocols include TCP and User Datagram Protocol (UDP), which is sometimes used instead of TCP for special purposes.

TOKEN PASSING, CSMA/CD AND TCP/IP 1/29/2019 18/21 PROTOCOL • The network layer, also called the internet layer, deals with packets and connects independent networks to transport the packets across network boundaries. The network layer protocols are the IP and the Internet Control Message Protocol (ICMP), which is used for error reporting. • The physical layer consists of protocols that operate only on a link -- the network component that interconnects nodes or hosts in the network. The protocols in this layer include Ethernet for local area networks (LANs) and the Address Resolution Protocol (ARP).

TOKEN PASSING, CSMA/CD AND TCP/IP 1/29/2019 19/21 PROTOCOL Advantages of TCP/IP

• TCP/IP is nonproprietary and, as a result, is not controlled by any single company. Therefore, the internet protocol suite can be modified easily. • It is compatible with all operating systems, so it can communicate with any other system. The internet protocol suite is also compatible with all types of computer hardware and networks. • TCP/IP is highly scalable and, as a routable protocol, can determine the most efficient path through the network.

TOKEN PASSING, CSMA/CD AND TCP/IP 1/29/2019 20/21 PROTOCOL THANK YOU

TOKEN PASSING, CSMA/CD AND TCP/IP 1/29/2019 21/21 PROTOCOL