查人人中国名人网用英语介绍大学校园:有谁能帮帮我翻翻这篇科技论文，前面一段是关于TCP的，啃了一天，还没翻六分之一
来源：百度文库 编辑：查人人中国名人网 时间：2024/04/27 21:25:29
Simulation-based study of TCP flow control mechanisms
using OPNET Modeler
Abstract
TCP is the most used transport protocol in Internet. It has a data
stream control based on TCP Window. This control
implementation has several options and there are still different
proposals to enhance it.
Algorithms like Slow Start, Congestion Avoidance, Fast
Retransmit and Fast Recovery are the basis for different TCP
flavors. Tahoe, Reno and New-Reno are TCP versions that use
these algorithms. This paper tries to give an overview of these
proposals. Several simulations have been run with OPNET in
order to acquire a better understanding of these algorithms and
the way they perform their functions.
Slow Start provides a way to control initial data flow at the
beginning of a communication and during an error recovery
based on received acknowledgements. Each acknowledgement
means that a segment, or a group of segments, has left the
network and is not using any resources, so new data can be sent.
Congestion Avoidance is an algorithm that adapts data
transmission to the available resources. After Slow Start has
reached a certain threshold, Congestion Avoidance starts
slowing down the opening of the window.
Introduction
TCP uses a sliding window protocol for data flow control. The
TCP window reports the number of bytes that each TCP process
is ready to receive in a certain moment. In other words, this is
the maximum amount of data that can be transmitted without
being acknowledged.
The receiver has a limited capacity to store received data and
this capacity has been advertised during the connection
establishment. During the communication, the received data fills
the receiver’s buffer, thus reducing the receiver’s capacity to get
more information. Available space will not be incremented until
the upper layer processes request for the received data. As the
upper layers process this information, receiver’s buffers get
more free space and the window is widened. The sender knows
how much data it is allowed to send because it receives segments
from the receiver advertising the offered window. These
segments are usually acknowledgement packets.
There are two types of windows depending on the point of view:
from the receiver, which sees its own window, and from the
sender, which sees the receiver’s window; so the former is called
the offered window and the latter is the usable window. The
offered window corresponds to the amount of buffer space
available in the receiver. On the other hand, the usable window
size is the offered window less the amount of data sent but not
acknowledged. Therefore, the usable window indicates the
number of segments the sender is allowed to send immediately.
[2] [8]
The algorithms and mechanisms discussed in this paper are
attempts to improve this window performance by changing some
aspects of its behavior as this window protocol has some
problems when transmission errors occur.
不好意思啊，看不懂。不过你可以去试试用金山词霸吧，可能会有用的。