多选题Which two methods are used to assign a route-distinguisher in a Kompella Layer 2 VPN?（）Aby assigning the RD under the routing-instancesBby assigning the RD under protocols bgpCby assigning the RD under routing-optionsDby assing the RD under policy-opti

For each blank，choose the best answer from the four choices and write down on the answer sheet.
（ ）is a six bytes OSI layer 2 address which is burned into every networking device that provides its unique identity for point to point communication.
（请作答此空）is a professional organization of individuals in multiple professions which focuses on effort on lower-layer protocols.
（ ）functions with two layers of protocols.It Can connect networks of different speeds and can be adapted to an environment as it expands.
（ ）is the popular LAN developed under the direction of the IEEE 802.5.
（ ）is the popular backbone technology for transmitting information at high speed with a high level of fault tolerance which is developed under the direction of ANSI.

A.ISO
B.ANSI
C.CCITT
D.IEEE

For each blank，choose the best answer from the four choices and write down on the answer sheet.
（ ）is a six bytes OSI layer 2 address which is burned into every networking device that provides its unique identity for point to point communication.
（ ）is a professional organization of individuals in multiple professions which focuses on effort on lower-layer protocols.
（请作答此空）functions with two layers of protocols.It Can connect networks of different speeds and can be adapted to an environment as it expands.
（ ）is the popular LAN developed under the direction of the IEEE 802.5.
（ ）is the popular backbone technology for transmitting information at high speed with a high level of fault tolerance which is developed under the direction of ANSI.

A.The hub
B.The bridge
C.The router
D.The proxy