For the following items，what is the mathematical relationship between the committed information  rate （CIR）， committed burst （Bc）， and committed rate measurement interval （Tc）？（）

Which switch port error is an indication of duplex mismatches on 10/100/1000 IEEE 802.3u  Gigabit Ethernet ports？（）

IEEE 802.1w is a Rapid Spanning Tree Protocol （RSTP） that can be seen as an evolution of the 802.1 standard. What are the port roles described by 802.1w？（）

Which one of the following potential issues is eliminated by using split horizon？（）

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

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

Which router is doing LSA type 7 to type 5 translation，and why？（）

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？（）

Choose two commands that are required to enable multicast on a router， when it is known that the receivers use a specific functionality of IGMPv3.（）

Which statement is true of a source that wants to transmit multicast traffic to group 239.1.1.1？（）