Lightstream公司研制的Lightstream2020是与Ethernet和FDDI具有直接接口的第一种ATM主干交换机。它可以接受HDLC和SDLC流量,网管人员可在56Kbps～2.048Mbps(E1)范围内设置WAN流量的端口速率。 更为出色的是,2020ATM交换机是以一种母板(midplane)体系结构为基础而设计制造的,这就使得可根据网络不同的需求而调整LAN和WAN接口板,不必替换昂贵的 Lightstream’s Lightstream 2020 is the first ATM backbone switch to interface directly with Ethernet and FDDI. It accepts HDLC and SDLC traffic, and network administrators can set the port rate for WAN traffic from 56Kbps to 2.048Mbps (E1). Even better, the 2020 ATM switches are designed and built on a midplane architecture that allows LAN and WAN interface boards to be tuned to the different needs of the network without having to replace expensive