What does the OSPF command capability vrf-lite achieve？（）

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

You are the network administrator of a Layer 3 switched network. Users in one VLAN are complaining that access to the server VLAN is very slow from time to time. Traffic in the local VLAN works without any issue， and users in other VLANs do not have any complaint to reach the server VLAN. What is most likely the cause of this issue？（）

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

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

Which message type is constructed and sent from an MSDP router to its MSDP peers when it  receives a PIM register message （knowing that the MSDP router is also configured as an RP for  the PIM domain）？（）

For the following ports， which port is on every bridge in a Spanning Tree Protocol IEEE 802.1w network except the root bridge？（）

Which statement best describes OSPF external LSAs （type 5）？（）

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？（）

f a Cisco switch is configured with VTPv1 in transparent mode， what is done with received VTP advertisements？（）