Network basic

天涯来客

1.  Network Basics: TCP/IP and OSI NetworkModel Comparisons

By Edward Tetz from Cisco Networking All-in-One For Dummies

Internet Protocol (IP) version 4 (IPv4)is the current standard “IP” protocol used with TCP/IP — Transmission ControlProtocol/Internet Protocol — which is the protocol for Internet addressing.Like the Open System Interconnection (OSI) model, TCP/IP has its own model.

The OSI model and the TCP/IP models wereboth created independently. The TCP/IP network model represents reality in theworld, whereas the OSI mode represents an ideal. The TCP/IP network modelmatches the standard layered network model as it should.

The following figure shows therelationship between the OSI model and the TCP/IP model.

http://file:///C:/Users/nxs/AppData/Local/Temp/msohtmlclip1/01/clip_image001.jpg

The TCP/IP network model has four basiclayers:

·        Network interface (layer 1): Deals with all physical componentsof network connectivity between the network and the IP protocol

·        Internet (layer 2): Contains all functionality thatmanages the movement of data between two network devices over a routed network

·        Host-to-host (layer 3): Manages the flow of trafficbetween two hosts or devices, ensuring that data arrives at the application onthe host for which it is targeted

·        Application (layer 4): Acts as final endpoints at eitherend of a communication session between two network hosts