All secure domain routers （SDRs） have shared attribute and resources. Which three resources are sharedall SDRs？ （）

A.All CE devices emulate a bridge
B.All provider devices emulate a bridge
C.Hierarchical VPLS reduces signaling overhead
D.Each PE device emulates a bridge
E.Each CE device emulates a bridge

A.TCP
B.UDP
C.HTTP
D.Multicast

A.It allows ITCM to send multiple upstream packets in one single large burst.
B.It reduces upstream data throughput.
C.It can be enabled/disabled from CMTS on per upstream port basis if desired
D.Concatenation activity on an interface can be checked by the show controller counters command