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assignmentutor-lab™ 为您的留学生涯保驾护航 在代写计算机网络computer networking方面已经树立了自己的口碑, 保证靠谱, 高质且原创的统计Statistics代写服务。我们的专家在代写计算机网络computer networking代写方面经验极为丰富，各种代写计算机网络computer networking相关的作业也就用不着说。

• Statistical Inference 统计推断
• Statistical Computing 统计计算
• (Generalized) Linear Models 广义线性模型
• Statistical Machine Learning 统计机器学习
• Longitudinal Data Analysis 纵向数据分析
• Foundations of Data Science 数据科学基础

## 计算机代写|计算机网络代写computer networking代考|Queuing Delay and Packet Loss

The most complicated and interesting component of nodal delay is the queuing delay, $d_{\text {quewe }}$ – In fact, queuing delay is so important and interesting in computer networking that thousands of papers and numerous books have been written about it [Bertsekas 1991; Kleinrock 1975, Kleinrock 1976]. We give only a high-level, intuitive discussion of queuing delay here; the more curious reader may want to browse through some of the books (or even eventually write a PhD thesis on the subject!). Unlike the other three delays (namely, $d_{\text {proc }}, d_{\text {trans }}$, and $d_{\text {prop }}$ ), the queuing delay can vary from packet to packet. For example, if 10 packets arrive at an empty queue at the same time, the first packet transmitted will suffer no queuing delay, while the last packet transmitted will suffer a relatively large queuing delay (while it waits for the other nine packets to be transmitted). Therefore, when characterizing queuing delay, one typically uses statistical measures, such as average queuing delay, variance of queuing delay, and the probability that the queuing delay exceeds some specified value.
When is the queuing delay large and when is it insignificant? The answer to this question depends on the rate at which traffic arrives at the queue, the transmission rate of the link, and the nature of the arriving traffic, that is, whether the traffic arrives periodically or arrives in bursts. To gain some insight here, let $a$ denote the average rate at which packets arrive at the queue ( $a$ is in units of packets/sec). Recall that $R$ is the transmission rate; that is, it is the rate (in bits/sec) at which bits are pushed out of the queue. Also suppose, for simplicity, that all packets consist of $L$ bits. Then the average rate at which bits arrive at the queue is $L a$ bits/sec. Finally, assume that the queue is very big, so that it can hold essentially an infinite number of bits. The ratio $L a / R$, called the traffic intensity, often plays an important role in estimating the extent of the queuing delay. If $L a / R>1$, then the average rate at which bits arrive at the queue exceeds the rate at which the bits can be transmitted from the queue. In this unfortunate situation, the queue will tend to increase without bound and the queuing delay will approach infinity! Therefore, one of the golden rules in traffic engineering is: Design your system so that the traffic intensity is no greater than 1.

Now consider the case $L a / R \leq 1$. Here, the nature of the arriving traffic impacts the queuing delay. For example, if packets arrive periodically-that is, one packet arrives every $L R$ seconds – then every packet will arrive at an empty queue and there will be no queuing delay. On the other hand, if packets arrive in bursts but periodically, there can be a significant average queuing delay. For example, suppose $N$ packets arrive simultaneously every $(L / R) N$ seconds. Then the first packet transmitted has no queuing delay; the second packet transmitted has a queuing delay of $L / R$ seconds; and more generally, the $n$th packet transmitted has a queuing delay of $(n-1) L / R$ seconds. We leave it as an exercise for you to calculate the average queuing delay in this example.

## 计算机代写|计算机网络代写computer networking代考|End-to-End Delay

Our discussion up to this point has focused on the nodal delay, that is, the delay at a single router. Let’s now consider the total delay from source to destination. To get a handle on this concept, suppose there are $N-1$ routers between the source host and the destination host. Let’s also suppose for the moment that the network is uncongested (so that queuing delays are negligible), the processing delay at each router and at the source host is $d_{\text {proc }}$, the transmission rate out of each router and out of the source host is $R$ bits/sec, and the propagation on each link is $d_{\text {prop. }}$. The nodal delays accumulate and give an end-to-end delay,
$$d_{\text {end-end }}=N\left(d_{\text {proc }}+d_{\text {trans }}+d_{\text {prop }}\right)$$
where, once again, $d_{\text {trans }}=L / R$, where $L$ is the packet size. Note that Equation $1.2$ is a generalization of Equation 1.1, which did not take into account processing and propagation delays. We leave it to you to generalize Equation $1.2$ to the case of heterogeneous delays at the nodes and to the presence of an average queuing delay at each node.

# 计算机网络代考

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## 计算机代写|计算机网络代写computer networking代考|端到端延迟

$$d_{\text {end-end }}=N\left(d_{\text {proc }}+d_{\text {trans }}+d_{\text {prop }}\right)$$
，其中$d_{\text {trans }}=L / R$，其中$L$是包大小。注意，等式$1.2$是等式1.1的一般化，它没有考虑处理和传播延迟。我们让您将方程$1.2$推广到节点上的异构延迟和每个节点上的平均排队延迟的情况

## 有限元方法代写

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## MATLAB代写

MATLAB 是一种用于技术计算的高性能语言。它将计算、可视化和编程集成在一个易于使用的环境中，其中问题和解决方案以熟悉的数学符号表示。典型用途包括：数学和计算算法开发建模、仿真和原型制作数据分析、探索和可视化科学和工程图形应用程序开发，包括图形用户界面构建MATLAB 是一个交互式系统，其基本数据元素是一个不需要维度的数组。这使您可以解决许多技术计算问题，尤其是那些具有矩阵和向量公式的问题，而只需用 C 或 Fortran 等标量非交互式语言编写程序所需的时间的一小部分。MATLAB 名称代表矩阵实验室。MATLAB 最初的编写目的是提供对由 LINPACK 和 EISPACK 项目开发的矩阵软件的轻松访问，这两个项目共同代表了矩阵计算软件的最新技术。MATLAB 经过多年的发展，得到了许多用户的投入。在大学环境中，它是数学、工程和科学入门和高级课程的标准教学工具。在工业领域，MATLAB 是高效研究、开发和分析的首选工具。MATLAB 具有一系列称为工具箱的特定于应用程序的解决方案。对于大多数 MATLAB 用户来说非常重要，工具箱允许您学习应用专业技术。工具箱是 MATLAB 函数（M 文件）的综合集合，可扩展 MATLAB 环境以解决特定类别的问题。可用工具箱的领域包括信号处理、控制系统、神经网络、模糊逻辑、小波、仿真等。

assignmentutor™您的专属作业导师
assignmentutor™您的专属作业导师