在网络计费问题上,有按使用时间收费的,有按通讯流量收费的,或者两个因素都考虑在内。然而,两种方法都是根据IP地址来收费的,这在某些场合就给一些人有机可乘。如图1所示,按规定机器A使用IP_A地址,机器B使用IP_B地址。但当A在使用Internet时,人为地将其机器的IP地址改为IP_B,其使用网络的费用就计在机器B上,这对B就不公平了,而A的费用却漏掉了。如果一个网段上出现多个类 In the network billing issues, there are charges according to the use of time, according to traffic charges, or both factors are taken into account. However, both methods are based on IP address to charge, which in some cases give some people take advantage of. As shown in Figure 1, according to the provisions of the machine A IP_A address, the machine B IP_B address. But when A is using the Internet, he artificially changed the IP address of his machine to IP_B, the cost of using the network was counted on Machine B. This was not fair to B, and A’s cost was missed. If there is more than one class on a segment