Embedded-Designing and Programming Small Devices for Networking

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The computers in the network must also agree on the following aspects of sharing the network:
•Rules for deciding when a computer may transmit on the network.When multiple computers share a data path,whether in a cable or wireless medium,the computers need to know when the path is available for transmitting.The Ethernet standard contains rules that specify when a
computer may transmit.
•A way of identifying a transmission's intended destination.In Ethernet networks,multiple computers may receive a message intended for one computer in the network. When a message arrives at a computer's network interface,the computer needs to know whether the message is intended for itself or another computer.Every communication in an Ethernet network includes a hardware address that identifies the Ethernet interface of the intended receiver. Some communications also use Internet protocols that contain additional addressing information,such as an addresses that identify the sending and receiving computers on the Internet and a port,or process,that receives the communication at the destination computer.