Refer to the exhibit.How many broadcast domains exist in theexhibited topology？（）

如何實現(xiàn)擁塞避免？

four switches， which one will be root switch.（no pic）.

一堆交換機一個server、一個transpare，問配置prune在哪里配置？

hsrp speak狀態(tài)是什么意思？

As a CCNA candidate,you must have a firm understanding of the IPv6 address structure.Refer to IPv6 address,could you tell me how many bits are included in each filed?（）

Which of the following describes the roles of devices in a WAN?（）

QoS Mechanisms：問在部署QoS中要用的3個mechanisms是什么？

The Frame Relay network in the diagram is not functioning properly.What is the cause of the problem?（） 

什么是NAT？