MME/SGW/SGSN GTPv2 Emulator

This is a new application that I've done recently, that is an evolution from the GTP Emulator that was only GTPv1.

I started to implement only the interface S5/S8 to interact with the PGW, but later on I also added the MME interface S11 and SGSN interface S4 towards the SGW.

This application has the following main interface:

This tab has the SGSN Gn part like the previous GTP Emulator App, with the addition of the UpdatePDPContext message, the SGW part with four GTPcV2 messages, and the MME/SGSN part with five GTPcV2 messages, but for nine types of procedures.

The App is ready to answer to CreateBearerRequest or UpdateBearerRequest sent from the PGW/SGW, even with DedicatedBearers (and with several bearers at the same time), and generally speaking, any message originated from the PGW or SGW nodes (DataDownlinkNotification, DeleteBearerRequest).

In the second tab of this app we have the QOS part, which is the same tab of the GTP Emulator App, plus the 4G part:

In this tab I added also the PCO bytes to send in the CreatePDPContext or CreateSessionRequest, mainly due the lack of space in the main tab.

The third tab is a Log, which shows some relevant information form the messages sent and receive. Here is an example:

The fourth tab is one of the most interesting ones. Is the test tab.

This part of the application allow us to do the following things using some specific CLI that I've created:

• Send any of the supported messages
• Set some specific parameters like QOS, Comon Flags, RAT Type, CGI/SAI/EGCI in these messages
• Set the IPs of the PGW or SGW for the following tests
• Set specific parameters (like the QOS or Event-Triggers) in other two Apps that I also have (OCS and PCRF Server), using an UDP interface and protocol that I've develop specific for this feature

For example the test presented in this next image is the Creation, Update and Delete of PDP Contexts, using different QOS, and different Common Flags values, to test all the possible combinations of a scenario that I needed to test:

Without this app, some of the combinations were impractical to reproduce and some would take a big amount of time. With this app, it toked less than one minute. Just check this cap file of the test above.

For example it's so easy to start a session in 4G, do an update to 3G, then an update to 2G, then an update to 4G, and so on, setting all the parameters accordingly. Things that in real live networks, using real terminals are very hard to achieve, and take lots, and lots of time.

With this tool: just seconds!

Again, this type of tools allow us to set non standard messages just to see how the nodes react to erroneous messages.