All the routers include a buffer in order to enqueue packets waiting to be transmitted. The behaviour of the routers' buffer is of primary importance when studying network traffic, since it may modify some characteristics, as delay or jitter, and may also drop packets. As a consequence, the characterization of this buffer is interesting, especially when real-time flows are being transmitted: if the buffer characteristics are known, then different techniques can be used so as to adapt the traffic: multiplexing a number of small packets into a big one, fragmentation, etc. This work presents a preliminary study of how to determine the technical and functional characteristics of the buffer of a certain device (as e.g. behaviour, size, limits, input and output rate), or even in a remote Internet network node. Two different methodologies are considered, and tested on two real scenarios which have been implemented; real measurements permit the estimation of the buffer size, and the input and output rates, when there is physical or remote access to the "System Under Test". In case of having physical access, the maximum number of packets in the queue can be determined by counting. In contrast, if the node is remote, its buffer size has to be estimated. We have obtained accurate results in wired and wireless networks.
翻译:所有路由器都包含一个缓冲器,以便将等待传输的包封封起来。路由器的缓冲行为在研究网络交通时至关重要,因为它可能改变某些特性,例如延迟或紧张,也可能降低包包。因此,这一缓冲的特征很有意思,特别是当实时流动正在传输时:如果知道缓冲特性,那么可以使用不同的技术来适应交通:将一些小包叠成一个大包,分割等等。这项工作初步研究如何确定某一设备缓冲的技术性和功能性特征(例如行为、大小、限制、输入和输出率),甚至可以在远程互联网网络节点中加以修改。考虑两种不同的方法,并根据已经实施的两种真实情景进行测试:如果知道缓冲特性,则实际测量可以估计缓冲大小,当实际或远程访问“测试系统”时,输入和输出率。在实际访问的情况下,可以确定队列中最大包装的技术和功能性特征(例如行为、大小、限制、输入率和输出率率),甚至在远程网络节点中进行计算。对比,如果不是远程,则可以估计其缓冲结果。