[问题1]
从图14-1可以看出，发送站硬件地址与IP地址长度分别是多少字节
参考答案：硬件地址长度是6字节，IP地址长度为4字节。
解析：sniffer通常在同一个网段的所有网络接口都有访问在物理媒体上传输的所有数据的能力，而每个网络接口都还应该有一个硬件地址，该硬件地址不同于网络中存在的其他网络接口的硬件地址，同时，每个网络至少还要一个广播地址。(代表所有的接口地址)，在正常情况下，一个合法的网络接口应该只响应这样的两种数据帧：
(1)帧的目标区域具有和本地网络接口相匹配的硬件地址。
(2)帧的目标区域具有“广播地址”。
| Cooperation is the common endeavor of two or more people to perform a task or reach a jointly cherished goal. Like competition and conflict, there are different forms of cooperation, based on group organization and attitudes. In the first form, known as primary cooperation, group and individual unite. The group contains nearly all of each individual’s life. The rewards of the group’s work are shared with each member. There is an interlocking identity of individual, group, and task performed. Means and goals become one, for cooperation itself is valued. While primary cooperation is most often characteristic of preliterate societies, secondary cooperation is characteristic of many modem societies. In secondary cooperation, individuals devote only part of their lives to the group. Cooperation itself is not a value. Most members of the group feel loyalty, but the welfare of the group is not the first consideration. Members perform tasks so that they can separately enjoy the fruits of their cooperation in the form of salary, prestige, or power. Business offices and professional athletic teams are examples of secondary cooperation. In the third type, called tertiary cooperation or accommodation, latent conflict underlies the shared work. The attitudes of the cooperating parties are purely opportunistic; the organization is loose and fragile. Accommodation involves common means to achieve antagonistic goals; it breaks down when the common means cease to aid each party in reaching its goals. This is not, strictly speaking, cooperation at all, and hence the somewhat contradictory term antagonistic cooperation is sometimes used for this relationship. |
The underlined word "fragile" in the last paragraph is closest in meaning to.
A．inefficient
B．easily broken
C．poorly planned
D．involuntary