-.. _platform:
-
.. raw:: html
- <object id="TOC" data="graphical-toc.svg" width="100%" type="image/svg+xml"></object>
+ <object id="TOC" data="graphical-toc.svg" type="image/svg+xml"></object>
<script>
window.onload=function() { // Wait for the SVG to be loaded before changing it
var elem=document.querySelector("#TOC").contentDocument.getElementById("PlatformBox")
Of course, this is only one possible way to model these things. YMMV ;)
.. _understanding_lv08
+
Understanding the default TCP model
-*****************************
+***********************************
When simulating a data transfer between two hosts, you may be surprised
by the obtained simulation time. Lets consider the following platform:
.. code-block:: xml
- <host id="A" speed="1Gf"/>
- <host id="B" speed="1Gf"/>
+ <host id="A" speed="1Gf" />
+ <host id="B" speed="1Gf" />
- <link id="link1" latency="10ms" bandwidth="1Mbps"/>
+ <link id="link1" latency="10ms" bandwidth="1Mbps" />
- <route src="A" dst="B>
- <link_ctn id="link1/>
+ <route src="A" dst="B">
+ <link_ctn id="link1" />
</route>
If host `A` sends `100kB` (a hundred kilobytes) to host `B`, one could expect
However, the default TCP model of SimGrid is a bit more complex than that. It
accounts for three phenomena that directly impact the simulation time even
on such a simple example:
+
- The size of a message at the application level (i.e., 100kB in this
example) is not the size that will actually be transferred over the
network. To mimic the fact that TCP and IP headers are added to each packet of