A.DLCI 17描述了R2和R3之間的ISDN線路
B.DLCI 17描述了一條在R2上的PVC 不能用在R3和R1上
C.DLCI 17是R2使用的二層地址，用來描述一條到R3的PVC
D.DlDLCI 17描述了一條從R2 R3到服務(wù)提供商撥號網(wǎng)絡(luò)

A.It divides the network communication process into smaller and simpler components, thus aiding component development, design, and troubleshooting.
B.It enables equipment from different vendors to use the same electronic components, thus saving research and development funds.
C.It supports theevolution of multiple competing standards, and thus provides business opportunities for equipment manufacturers.
D.It encourages industry standardization by defining what functions occur at each layer of the model.
E.It provides a means by which changes in functionality in one layer require changes in other layers.

A.BSS
B.ESS
C.IBSS
D.SSID

A.The new IOS image is too large for the router flash memory.
B.The TFTP server is unreachable from the router.
C.The new IOS image is not correct for this router platform.
D.The IOS image on the TFTP server is corrupt.
E.There is not enough disk space on the TFTP server for the IOS image.

A.RSTP significantly reduces topology reconverging time after a link failure.
B.RSTP expends the STP port roles by adding the alternate and backup roles.
C.RSTP portatates are blocking,discarding,learing,orforwarding.
D.RSTP also uses the STP proprsal-agreement sequence.
E.RSTP use the same timer-baseed process as STP on point-to-point links.
F.RSTP provides a faster transition to the forwarding state on point-to-point links than STP does.