Which three are the ATM cell header fields？（）

多项选择题WhenyoudesignQoSonCEforanMPLSLayer2VPN，whichthreethingsshouldbeconsidered？（）

A.Layer 2 access link QoS design
B.enterprise-to-service-provider mapping models
C.Layer 3 link access QoS design
D.service provider service level agreements
E.Layer 2 link access load balancing

单项选择题WhichdescriptionofBGPauthenticationistrue？（）

A.MD5 has been used by BGP to encrypt BGP update packets.
B.BGP uses a message-digest algorithm to authenticate BGP peers
C.A plain-text password authentication is an option of BGP authentication
D.EBGP peers authentication is faster than IBGP peers authentication
E.BGP uses public key and private key to authenticate BGP peers.

单项选择题WhatisthetypicalmarkedDSCPvalueforavoicesignalingpacketinVoIPtechnology？（）

A.BE
B.AF41
C.AF21
D.EF
E.AF31

多项选择题Whichthreestatementsabouttheroutetarget（RT）aretrue？（）

A.The RT is a BGP extended community.
B.The RT is an 8-byte field that is prefixed to an IPv4 address to make it a unique VPNv4 address.
C.When a VPN route that is learned from a CE router is injected into BGP， one or more RTs are associated with it
D.The distribution of VPN routing information is controlled through the use of VPN RTs
E.When a VPN route that is learned from a CE router is injected into BGP， there is always one RT that is associated with it.

多项选择题WhichthreeofthesearetypesofEthernetVirtualConnections（EVCs）intheMEFconcept？（）

A.rooted multipoint EVC （E-Tree）
B.point-to-point EVC （E-Line）
C.point-to-multipoint EVC （E-Tree）
D.hub spoke EVC （E-Tree）
E.multipoint-to-multipoint EVC （E-LAN）