英语翻译1 Therefore,in most large star networks ,backup systems

英语翻译1 Therefore,in most large star networks ,backup systems are available in case the primary system fails.2 A communication channel is the facility by which data is transmitted between locations in a computer network.3 The major advantages of these hair-like fibers over wire cables include substantial weight and size savings and increased speed of transmission.4 Most importantly,the OSI reference model is a framework that you can use to understand how information travels throughout a network.5 It prevents changer in one layer from affecting he other layers,so that they can develop more quickly.6 The problem of moving information between computers is divided into seven smaller and more manageable problems in the OSI reference model.7 Each individual OSI layer has a set of functions that it must perform in order for data packets to travel from a source to a destination on a network.8 The application layer establishes the availability of intended communication partners,9 synchronizes and establishes agreement on procedures for error recovery and control of data integrity.10 Whereas the application,presentation,and session layers are concerned with application issues,the lower four layers are concerned with data transport issues.11 The purpose of a repeater is regenerate and retime network signals at the bit level to allow them to travel a longer distance on the media.12 What really defines a bridge is its layer 2 filtering of frames and how this is actually accomplished.13 The difference between the hub and switch is that switches make decisions based on MAC addresses and hubs don’tmake decisions at all.14 The purpose of a switch is to concentrate connectivity,while making data transmission more efficient.15 The physical topologies that are commonly used are the bus,ring.Star ,Extended star,Hierarchical,and mesh.16 A hierarchical topology is created similar to an extended star.But instead of linking the hubs/switches together,the system is linked to a computer that controls the traffic on the topology.17 There is no order the stations follow to use the network.It is first come ,first serve.This is the way that Ethernet works.18 The TCP/IP reference model and the TCP/IP protocol stack make data communication possible between any two computers ,anywhere in the world,at nearly the speed of light.19 The TCP/IP combines all application-related issues into one layer,and assures this data is properly packaged for the next layer.20 IP serves as a universal protocol that allows any computer,anywhere,to communicate at any time.能翻译的比较准确的帮下忙啊....1楼的翻译有些问题...