📄 packet.html
字号:
<html><head><title>Packet</title></head><body background="parchment.gif" tppabs="http://nile.wpi.edu/NS/Icons/parchment.gif" text="#000000" link="#0000FF"vlink="#000080" alink="#FF0000"><br><center><h2>Packet</h2></center><br><br><dl><p>A NS packet is composed of a stack of headers, and an optional dataspace (see Figure 12). As briefly mentioned in the "Simple SimulationExample" section, a packet header format is initialized when aSimulator object is created, where a stack of all registered (orpossibly useable) headers, such as the common header that is commonlyused by any objects as needed, IP header, TCP header, RTP header (UDPuses RTP header) and trace header, is defined, and the offset of eachheader in the stack is recorded. What this means is that whether ornot a specific header is used, a stack composed of all registeredheaders is created when a packet is allocated by an agent, and anetwork object can access any header in the stack of a packet itprocesses using the corresponding offset value. </a><p align="center"><img src="fig12.gif" tppabs="http://nile.wpi.edu/NS/Figure/fig12.gif"><br><br><b>Figure 12.</b> NS Packet Format</p>Usually, a packet only has the header stack (and a data space pointerthat is null). Although a packet can carry actual data (from anapplication) by allocating a data space, very few application andagent implementations support this. This is because it is meaninglessto carry data around in a non-real-time simulation. However, if youwant to implement an application that talks to another applicationcross the network, you might want to use this feature with a littlemodification in the underlying agent implementation. Another possibleapproach would be creating a new header for the application andmodifying the underlying agent to write data received from theapplication to the new header. The second approach is shown as anexample in a later section called "Add New Application and Agent".</p></dl></body></html>⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -