Kernel GTP » History » Revision 3
Revision 2 (laforge, 02/23/2017 05:59 PM) → Revision 3/12 (laforge, 02/23/2017 05:59 PM)
h1. OpenGGSN and Linux Kernel accelerated GTP-U
OpenGGSN has support to use the Linux kernel GTP-U code to accelerate the data/user plane while still implementing the control plane (GTP-C) in userspace in OpenGGSN.
For more information about the Linux kernel GTP-U code, please see [[linux-kernel-gtp-u:]]
h2. Building OpenGGSN with kernel which has GTP-U support
At the time of writing (2017-01-09) of this wiki, below listed distributions have support of GTP kernels :
* Debian 4.9.1-1~exp1 - Debian's latest experimental build
* Ubuntu 16.10 kernel 4.8
* OpenSUSE Tumbleweed (stable) 4.8 (.12)
* Fedora 25 kernel 4.8
Following two Debian kernels do not activate GTP kernel module during build: 4.8.0 and 4.9.0.
*It is expected that complete openbsc project and related dependencies are pre-installed.*
Check if package @libc-ares-dev@ is installed and if not please add it.
Ubuntu 16.10, kernel 4.8.0-30-generic is used.
* Installing dependencies and build library @libgtpnl@
You can install those packages with:
<pre>
sudo apt install libtalloc-dev libpcsclite libmnl-dev
</pre>
Please follow instructions provided at [[cellular-infrastructure:Build from source]] in order to install following library and projects :
Information about dependencies between Osmocom projects is given at the above link:
* libgtpnl
<pre>
sudo make install
sudo ldconfig
</pre>
* libosmocore
* openggsn
<pre>
./configure --enable-gtp-linux
make
sudo make install
sudo ldconfig
</pre>
Following message is shown at end of the command: @ ./configure --enable-gtp-linux@
<pre>
openggsn Configuration:
GTP Linux kernel support: yes
</pre>
This means that appropriate header files are available.
h2. Using OpenGGSN with kernel which has GTP-U support
In order to find out whether gtp.ko module is available we can enter following command:
<pre>
find /lib/modules/`uname -r` -name gtp.ko
</pre>
Output below shows that gtp.ko module is present:
<pre>
/lib/modules/4.8.0-30-generic/kernel/drivers/net/gtp.ko
</pre>
We are loading module gtp from kernel issuing command: <pre>sudo modprobe gtp </pre>
when you enter:
<pre>
lsmod | grep gtp
</pre>
then more information about gtp and related udp tunnel can be obtained:
<pre>
gtp 28672 0
udp_tunnel 16384 1 gtp
</pre>
Some helpful tools are available in: @libgtpnl/tools@
you can get more details about gtp-tunnel, entering command from the OpenGGSN shell:
<pre>
sudo ./gtp-tunnel list
</pre>
Output will be similar to:
<pre>
version 1 tei 1/0 ms_addr 192.168.0.2 sgsn_addr 127.0.0.2
</pre>
Furthermore we can use: <pre> sudo starce ggsn --gtp-linux -c ggsn.conf -f -d </pre> to determine if Ubuntu 16.10, kernel 4.8.0-30 is in use.
Next two cases shall be considered as an indication whether gtp kernel module is active:
** If gtp kernel module is active then we can see the strace output just when PDP context activation or deactivation is done.
** If gtp kernel module is not active then we can see the strace output constantly running on the screen.
Note: OpenGGSN is started by:
<pre>
sudo ggsn --gtp-linux -c ggsn.conf -f -d
</pre>
-d option is useful for debugging purposes.
Related output should be similar to the one shown below:
<pre>
conf: ggsn.conf
fg: 1
debug: 1
qos: 0x0b921f
apn: internet
net: 192.168.0.0/24
pidfile: /var/run/ggsn.pid
statedir: /var/lib/ggsn/
gtp_linux: 1
timelimit: 0
cmdline_parser_configfile
listen: 127.0.0.1
conf: ggsn.conf
fg: 1
debug: 1
qos: 0x0b921f
apn: internet
net: 192.168.0.0/24
pidfile: /var/run/ggsn.pid
statedir: /var/lib/ggsn/
gtp-linux: 1
timelimit: 0
<000c> gtp.c:701 GTP: gtp_newgsn() started
<0002> gtp-kernel.c:123 Using the GTP kernel mode (genl ID is 27)
<0002> gtp-kernel.c:156 GTP kernel configured
<000b> control_if.c:693 CTRL at 127.0.0.1 4257
</pre>
osmosgsn can be started with:
<pre>
sudo osmo-sgsn -c sgsn.cfg
</pre>
- d option is also available ins osmo-sgsn command.
Additional information related to setup of openbsc and GPRS setup is available [[cellular-infrastructure:OpenBSC GPRS]]
For clarity purposes configuration files of openbsc, OpenGGSN, osmosgsn and sysmoBTS are added.