History
The earliest LAN switches were developed in 1990. They were Layer 2 devices (bridges) dedicated to solving desktop bandwidth issues. Recent LAN switches evolved to multilayer devices capable of handling protocol issues involved in high-bandwidth applications that historically have been solved by routers. Today, LAN switches are used to replace hubs in the wiring closet because user applications demand greater bandwidth.
LAN Switch Operation
LAN switches are similar to transparent bridges in functions such as learning the topology, forwarding, and filtering. These switches also support several new and unique features, such as dedicated communication between devices through full-duplex operations, multiple simultaneous conversations, and media-rate adaption.
Full-duplex communication between network devices increases file-transfer throughput. Multiple simultaneous conversations can occur by forwarding, or switching, several packets at the same time, thereby increasing network capacity by the number of conversations supported. Full-duplex communication effectively doubles the throughput, while with media-rate adaption, the LAN switch can translate between 10 and 100 Mbps, allowing bandwidth to be allocated as needed.
Deploying LAN switches requires no change to existing hubs, network interface cards (NICs), or cabling.
參考答案:历史
早在1990年制定了局域网交换机. 他们是2层设备(桥)致力于解决频宽问题桌面. 最近演变到多层局域网交换机设备能力处理议定书涉及的高带宽应用,历史上已经解决了路由器. 今天,兰开关来代替枢纽接线壁橱因为用户应用需求更大的带宽. 蓝鸿震开关操作开关类似透明桥功能如学习拓扑学、传递和过滤. 这些交换机还支持几种新的特色,例如专用通讯设备之间通过全双工业务 多重同步通话、媒体速率适应. 全双工通信网络设备加档案移交的吞吐量. 同时也出现了多次交谈转发或开关,几个包在同一时间, 从而提高网络容量的数字通话支持. 全双工吞吐量双打有效沟通,同时与媒体速率适应性、 局域网交换机可将10至100Mbps之间,允许按需要分配带宽来. 部署局域网交换机不需要改变现有枢纽、网络接口卡(网卡)或布线.
