Multicast is being deployed in the network， and only ip pim sparse-dense mode has been configured on all interfaces in the network to support a new video streaming application. No other multicast configuration was applied anywhere in the network. Since enabling multicast， the network monitoring tools show periodic spikes in link utilization throughout the network， even in areas where the video application is not being used. What could be a possible cause？（）

What is the STP root guard feature designed to prevent？（）

Policy-based routing allows network administrators to implement routing policies to allow or deny paths based on all of these factors except which one？（）

Which QoS mechanism can help classify different kinds of Citrix traffic （print job versus real-time terminal control）？（）

Which three protocols should be explicitly managed by using Control Plane Policing on an Internet border router？（）

An administrator of a peer-to-peer server application reports that the maximum bandwidth that his application receives is 90 Mb/s. You have an 8-port，100-Mb/s EtherChannel bundle on the switching infrastructure between the two servers， resulting in a bidirectional throughput of more than what is recorded. Which two solutions would allow for more bandwidth for the application？（）

What does a unicast prefix-based IPv6 multicast address start with？（）

What is the command to configure RSVP to reserve up to one-tenth of a Gigabit link， but only allow each individual flow to use 1 MB/s？（）

Which statement is correct about an OSPF sham-link？（）

Which three are needed to run VRF lite for IPv6 on a router？ （）