Chapter 2 Communicating over the Network
Process running on the 侃侃而谈intermediary network devices perform the functions:
1) Regenerate and retransmit data signals
2) Maintain information about what pathways exist through the network and internetwork
3) Notify other devices of errors and communication failures
4) Direct data along alternate pathways when there is a link failure
5) Classify and direct messages according to QoS priorities
6) Permit or deny the flow of data, bad on curity ttings
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Physical Port - A connector or outlet on a networking device where the media is connected to a host or other networking device.just about enough
Interface - Specialized ports on an internetworking device that connect to individ
ual networks. Becau routers are ud to interconnect networks, the ports on a router are referred to network interfaces.
just becau Networking protocols suites（协议束） describe process such as:
1) The format（格式） or structure of the message
2) The process by which networking devices share information about pathways with other networks
3) How and when error and system messages are pasd between devices
4) The tup and termination （终结）of data transfer ssions
经典英语演讲 The nding and receiving Process
eliminatedThe Application layer protocol, HTTP, begins the process by delivering the HTML formatted web page data to the Transport layer. There the application data is broken into TCP gments. Each TCP gment is given a label, called a header, containing informatiowa
on about which process running on the destination computer should receive the message.abc news It also contains the information to enable the destination process to reasmble the data back to its original format.
The Transport layer encapsulates the web page HTML data within the gment and nds it to the Internet layer, where the IP protocol is implemented. Here the entire TCP gment is encapsulated within an IP packet, which adds another label, called the IP header. puppyThe IP header contains source and destination host IP address, as well as information necessary to deliver the packet to its corresponding destination process.
workshop是什么意思Next, the IP packet is nt to the Network Access layer Ethernet protocol where it is encapsulated within a frame header and trailer. Each frame header contains a source and destination physical address. The physical address uniquely identifies the devices on the local network. The trailer contains error checking information. Finally the bits are encoded onto the Ethernet media by the rver NIC.
