Commit 10c9694a authored by Robert Ricci's avatar Robert Ricci
Browse files

Added a section on naming - control net vs. experimental net naming,

and the different names we put into /etc/hosts
parent 0d6e2480
......@@ -44,6 +44,8 @@
<li> <a href="#UTT-Swapping">What is Swapping?</a>
<li> <a href="#UTT-8">How can I get switch statistics (such as packet
counts) for my experiment?</a>
<li> <a href="#UTT-Naming">What names should I use to refer to the
nodes in my experiment?</a>
</ul>
<li> <a href="#HDS">Hardware setup</a>
......@@ -584,7 +586,7 @@
as well.
</p>
<li><a NAME="UTT-8"></a>
<li><a NAME="UTT-8"></a>
<h3>How can I get switch statistics (such as packet counts) for my
experiment?</h3>
<p>
......@@ -600,7 +602,67 @@
Note that the numbers returned by <code>portstats</code> do not get
reset between experiments.
</p>
<li><a NAME="UTT-Naming"></a>
<h3>What names should I use to refer to the nodes in my
experiment?</h3>
<p>We set up names for your nodes in DNS, for use from outside,
and <code>/etc/hosts</code> files for use on the nodes in the experiment.
Since our nodes have multiple interfaces (the control network, and,
depending on the experiment, possibly several experimental interfaces,)
determining which name refers to which interface can be somewhat
confusing. The rules below should help you figure this out.
</p>
<ul>
<li><b>From the outside world</b> -
We set up names in the form
<code><i>node</i>.<i>expt</i>.<i>proj</i>.emulab.net</code> in DNS,
so that they visible anywhere on the Internet. This name always refers
to the node's control network interface, which is the only one
reachable from the outside world.
</li>
<li><b>On the nodes themselves</b> -
There are three basic ways to refer to the interfaces of a node. The
first is stored in DNS, and the second two are stored on the node in
the <code>/etc/hosts</code> file.
<ol>
<li><i>Fully-qualified hostnames</i> - These names the same ones
visible from the outside world, and referred to by attaching the
full domain name: ie.
<code><i>node</i>.<i>expt</i>.<i>proj</i>.emulab.net</code>. (note
that, since we put <code>.emulab.net</code> in nodes' domain
search paths, you can use
<code><i>node</i>.<i>expt</i>.<i>proj</i></code> as a shorthand.)
This name always refers to the control network
</li>
<li><i><code>node-link</code> form</i> - You can refer to an
individual experimental interface by suffixing it with the name of
the link or LAN (as defined in your NS file) that it is a member
of. For example, <code>nodeA-link0</code> or
<code>server-serverLAN</code>. This is the preferred way to refer
to experimental interfaces, since it uniquely and unambiguously
identifies an interface.
</li>
<li><i>Short form</i> - If a node is directly connected to the
node you're on, you can refer to that node simply with its name
(eg. <code>nodeA</code>.) Note that this differs from the fully-
qualified name in that no domain is given. If you have enabled
<a href="#SWS-5">routing</a>, we also create short names for
any node that you have a route to. However, if two nodes are
connected with more than one interface, or there is more than
one route between them, there is no guarantee that the short name
has been associated with the one is on the 'best' (ie. shortest or
highest bandwidth) path - so, if there is ambiguity, we strongly
suggest that you use the <code><i>node-link</i></code> form.
</li>
</li>
</ul>
</ul>
<hr>
......@@ -704,6 +766,8 @@
file /etc/hosts . It shows the IP addresses and aliases that refer
to the different experimental interfaces. These are the names/IPs
you can use to see the delays.
</p>
<p>
For instance, let's say I have an experiment that had NodeA and
NodeB connected with a shaped link. The file /etc/hosts on NodeA
......@@ -714,6 +778,12 @@
didn't configure manually corresponds to an unshaped link.
</p>
<p>
For a discussion of the way to 'name' interfaces on the control
and experimental networks, see the the <a href="#UTT-Naming">naming
section</a> of this document.
</p>
</ul>
<hr>
......
Supports Markdown
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment