多项选择题
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.
单项选择题 You and a co-worker have established wireless communication directly between your wireless laptops. What type of wireless topology has been created（）。
单项选择题 When upgrading the IOS image, the network administrator receives the exhibited error message. What could be the cause of this error（）。
多项选择题 Which three statements about RSTP aretrue?（）