These instructions show you how to install the P2PNS implementation for Linux. Compiling for Windows is currently not supported.

1. Download and install [http://www.oversim.org/ OverSim] according to the these [http://www.oversim.org/wiki/OverSimInstall install instructions].

2. Download the modified OpenSER SIP proxy [http://www.p2pns.org/chrome/site/openser-1.3.1-p2psip-20080926.tgz openser-1.3.1-p2psip-20080926.tgz] and extract in next to your !OverSim installation:
{{{
  cd ~/sim
  tar xzf /tmp/openser-1.3.1-p2psip-20080926.tgz
}}}

3. Compile and install OpenSER:
{{{
  cd ~/sim/openser-1.3.1-p2psip
  make prefix=`pwd/install` install
}}}

4. Edit openser-1.3.1-p2psip/install/etc/openser/openser.cfg and change the following parameters:
{{{
  listen: change this to the local IP
  mpath: change this to the module path of your OpenSER installation
         (e.g. /home/user/sim/open-1.3.1-p2psip/install/lib/openser/modules/)
}}}

5. Edit !OverSim-20080919/Simulations/realworld/realdhtapp.ini and remove the bootstrap IP (since this is the first node in the overlay):
{{{
   bootstrapIP: replace the "10.6.0.1" by ""
}}}

6. Start !OverSim and click on the "FAST" button:
{{{
  cd ~/sim/OverSim
  bin/OverSim -f Simulations/realworld/realdhtapp.ini 
}}}

7. Start OpenSER (in a new terminal):
{{{
  cd ~/sim/openser-1.3.1-p2psip
  install/sbin/openser -f install/etc/openser/openser.cfg
}}}

8. Start and configure a SIP UA of your choice (e.g. [http://www.ekiga.org/ Ekiga]):
{{{
  - Set the outgoing proxy to ''localIP'':5061
    (With Ekiga: ''Edit->Preferences->SIP Settings->Outbound Proxy''
  - Create a new SIP account with an arbitrary username and the domain ''p2p'' (e.g. alice@p2p)
    (With Ekiga: ''Edit->Accounts->Add'': Account Name and User ''alice'' and Registrar ''p2p'')
  - Register the account at the local SIP proxy
    (With Ekiga: ''Edit->Accounts'': Click the checkbox next to the account, if it's not already registered)
}}}

Congratulations - now you should have a running P2PNS installation. With this setup you could connect a second SIP UA to the same local proxy and start a call between the two UAs.

Of course a peer-to-peer network with a single node is not very interesting ;-) You have to alternatives to add additional overlay nodes:

=== Emulation of additional nodes by using the tun interface (needs root privileges) ===

5a. Adapt !OverSim-20080919/Simulations/realworld/setup-realdht to your environment (username and LD_LIBRARY_PATH). If you removed the bootstrapIP paramter from realdhtapp.ini in step 5 restore the old "10.6.0.1" setting.

6a. Start !OverSim, enter your password and click on the "FAST" button for both !OverSim processes:
{{{
  cd ~/sim/OverSim/Simulations/realworld
  ./setup-realdht 
}}}

In this configuration there is a second !OverSim process emulating 10 additional overlay nodes.

=== Adding additional overlay nodes (you need multiple machines for this) ===

9. Install OverSim and OpenSER on a second machine.

10. Now change realdhtapp.ini on the second machine:
{{{
  - Replace the run number (''Run'' and ''default-run'') by a unique number for each node
    (Otherwise all nodes will have the same nodeID!)
  - Set bootstrapIP to the IP of the first overlay node

11. Start OverSim and OpenSER on the second machine (see steps 6 and 7).