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

单项选择题WhichstatementaboutVPLSistrue？（）

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

单项选择题Whatmethodofstreaminglivevideoistheleasttaxingonbandwidthinalargeenterpriseenvironment？（）

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

单项选择题WhichstatementisFALSEconcerningConcatenation？（）

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

单项选择题Inopticaltransmissionsystems，chirpedlasersareusedforthepurposeof：（）.

A.Turning the laser to a specific ITU channel
B.Keeping the signal wavelength "locked" to a specific technology
C.Suppressing FWM and SBS non-linear effects
D.None ofthe above

单项选择题WhatlayeroftheTMN（telecommunicationsmanagementnetwork）modeldoesCTMfitinto？（）

A.Network management layer
B.Element management layer
C.Business management layer
D.Network element layer