计算机帧中继技术技术总结.ppt

Purpose: This figure provides an overview of terminology so that the student is prepared to understand the Frame Relay operation discussion. The terminology used with Frame Relay varies by service provider. These are the commonly used terms. Point out the local access loop and note that the local access rate is different than the rate used within the Frame Relay cloud. The DLCI is of local significance, therefore, point out that the same DLCI can be used in multiple places in the network. The autosensing LMI is a Release 11.2 or later feature. Frame Relay connections are made using PVCs. The circuits are identified by the DLCI assigned by the service provider. Reference: For more information on Frame Relay, including a Frame Relay glossary, refer to the Frame Relay Forum World Wide Web page: /4000/4003.html This course does not discuss Frame Relay traffic flow issues. So terms like BECN, FECN and discard eligible are not discussed in this course. These terms are some of the terms that can be found in the Frame Relay Forum’s glossary. The BCRAN discusses Frame Relay traffic flow issues. Purpose: This figure is a transition discussion to illustrate the need for subinterfaces. Now that students are familiar with the concept and configuring of Frame Relay, they are ready to consider the issues and solutions related to broadcast updates in an NBMA Frame Relay network. Emphasize: Compare the different topologies described. Explain that by default interfaces that support Frame Relay are multipoint connection types. This type of connection is not a problem when only one PVC is supported by a single interface; but it is when multiple PVCs are supported by a single interface. In this situation, broadcast routing updates received by the central router cannot be broadcast to the other remote sites. Broadcast routing updates are issued by distance vector protocols. Link-state and hybrid protocols use multicast and unicast addresses. Purpose: This figure illustrates ma