Connect on SS7 or Sigtran.

SS7 is a legacy signaling network for telephony. Nowadays new service providers are coming into the market. Telecom mobile operators have plenty of network resources available.  By providing access to the network an operator can earn more.

To create new revenue streams, a mobile operator opens the SS7 network contentions to VAS, Messaging, USSD, or any other service provider.

A service provider can utilize the available resources and add more revenues to an operator. Service providers buy the ss7 messages or MSUs in bulk and use these MSUs for providing value-added services (e.g SMS etc.). This tutorial will explain,  how you can connect to the ss7 network for setting up a service?

 Bulk SMS service and HLR lookup service:  

Messaging is a basic need in every corner of the world. It could be for banking, retail, or anything.  Mostly a messaging provider connects to one or more mobile operators over SMPP. As it’s easy to set up messaging over SMPP. To an end-user ( a brand like Amazon), an SMS provider exposes HTTP-based APIs, or again it could be SMPP.

Connecting on SS7 rather than SMPP opens new verticals that are beneficial to all. This offloads the  SMSC of a mobile operator and gives more real-time insight into messaging to a provider.  An ss7 connection can be set up on special hardware [TDM Links (E1/T1)]  or on over IP[ Sigtran].

If messaging has to be on TDM, then the messaging server or SMSC should be placed at the operator’s premises. This is generally discouraged because it requires extra space and resources in the operator data center. For that, they may ask for a commitment to a minimum guarantee.

With Sigtran, the messaging application can connect to the ss7 network over the Internet. A service provider sets up the bulk SMS or HLR lookup software in a data center and configures Sigtran links with the mobile operator’s core network via STP.

How to Get or download ss7 stack software?

To connect, the first thing is to get the ss7 software stack.  There are two options to get it. First is a commercial version, with this option you need to contact the sales team of a software company.  Once the sales team knows your requirement and agrees to give the required software, then you can download the ss7 stack and use it with a license.

Might be you will get a trial license so that you can develop an application without spending initially and later go for a purchase.  Dialogic is one of the companies, which provides the download of  ss7 software with the stack, programming manuals, and application development libraries.  The stack can work in trial mode.  Which is sufficient for unit testing or development for providing a POC.

The second option is open source, you can get help from forums and from documents available online.   Generally, you need to be more expert if you want to use an open-source ss7 stack. You should be ready to add missing features you might need. As all, you need to do it yourself if you need it for free.

Sometimes an open source also has the option to purchase the commercial version. So again this will become the same as a commercial one.

Steps and configuration settings for an SS7 Connection.

VPN Setup: 

When using Sigtran, communication is over the public IP network(Internet).  That opens the vulnerability for attack or hacking. The connection should be over a secure and encrypted channel. The first level of security is achieved by setting up a VPN or virtual private network between operator and service provider. Both parties agreed on a preshared key for encryption to set up a VPN.

Sigtran/SS7 configuration :

In a network, before initiating any communication both ends should know each other.  The configuration parameters include the addressing of Sigtran and ss7 layers. This example Includes configuration parameters for using M3UA as the Sigtran layer.  Both parties need to decide the role of nodes on each side. The mobile operator opens a connection to its Signaling Gateway (SG). The SG is a router, from which a destination can be reached.

SCTP Parameters:

This represents the parameters required to set up an SCTP link between two nodes.  Sigtran uses SCTP as transport for carrying ss7 signaling.

Mobile Operator Bulk SMS /HLR lookup vendor (SMSC) 
IP AddressThis is the IP Address of Signaling GatewayIP AddressIP Address of the SMSC
SCTP PortA port number, which will be used on Signaling Gateway. SCTP Port A port number will be used on SMSC.
Mode (Client/Server)Whether SG will initiate SCTP connection or SMSC. Here assumed SG is a server Mode (Client/Server) Whether SMSC will initiate SCTP connection or SG. Here assumed SMSC is a client.

SCCP Parameters:

Once SCTP configuration parameters are fixed. Now it’s time to configure the use of SCTP, which is M3UA.

Mobile Operator Bulk SMS /HLR lookup vendor (SMSC) 
Network Appearance (NA)An optional integer value has significance between SMSC and SG.Network Appearance (NA)An optional integer value has significance between SMSC and SG.
Routing Context (RC)An optional integer value identifies the application server on SMSC.Routing Context (RC)An optional integer value identifies the application server on SMSC.
Network Indicator.An integer value, that identifies if a network is National or International.Network Indicator. An integer value, that identifies if a network is National or International.

SCCP Parameters:

SCCP is the service user of M3UA.  SCCP does the routing based on the global tile address. Layers send messages to the called party and calling party address to the M3UA layer.

Mobile Operator Bulk SMS /HLR lookup vendor (SMSC) 
Global TitleThis is a string of digits. These digits globally identify the Signaling GatewayGlobal TitleThis is a string of digits. These digits globally identify the Signaling Gateway.
Point CodeAn Integer value. It is an MTP3 layer config parameter.Point CodeAn Integer value. It is an MTP3 layer config parameter.

Message Flows :

At first, the SCTP level connection is set up. This includes a four-way handshake at SCTP Level.  The result of this is an indication for SCTP CommUP to M3UA.  M3UA starts alignment for AS, to bring point codes UP.