What features set is most frequently used to prevent hackers from flooding a port with MAC- addresses？（）

单项选择题ATT（Attached）bitneedstobesetinthelinkstatePDUsinanIS-ISlevel-1-2routertoindicatethattheyareapotentialexitpointoutofthearea.（）

A.True
B.False

单项选择题Whatisthestatisticalreserve？（）

A.Bandwidth that is reserved for SVCs to route over a trunk
B.Bandwidth that is reserved on a trunk so that ABR connections can burst
C.Bandwidth on a trunk that is reserved for control traffic and cannot be used by connections
D.Bandwidth that cannot be allocated to connections but can be used to accommodate statistical variations in the traffic

单项选择题WhatisTCI？（）

A.Tag Calling Interface
B.Tag Control Identifier
C.ToS Class Interface
D.Tag Control Information

多项选择题Inwhichmodesdoesselectivepacketdiscard（SPD）operate？（）

A.normal
B.discard
C.random
D. full

多项选择题WhichtwostatementsaboutVPLSaretrue？（）

A.There is a full mesh of pseudowires.
B.There is a partial mesh of pseudowires.
C.Only L2TPv3 can be used for pseudowire establishment.
D.There is split-horizon to avoid loops.