Short Message Service Center (SMSC)

What is an SMSC?

A Short Message Service Center (SMSC) is a network element in the mobile telephone network which delivers SMS messages. It has SMS message forwarding and SMS message storing functionality.

In more detail an Short Message Service Center (SMSC) is responsible for handling the SMS operations of a wireless network or an SMS service provider. When an SMS message is sent from a mobile phone (or from a computer), it will reach an SMS center first. The SMS center then forwards the SMS message towards the destination. An SMS message may need to pass through more than one SMSC, before it reaches the destination. The main role of an SMSC is to store and forward SMS messages and regulate the process. It also provides billing support for the carriers.

If the recipient of an SMS messages is unavailable (for example, when the mobile phone is switched off), the SMS center will store the SMS message for a period of time. This time can be adjusted by the message sender the network maximum is usually one week. It the recipient becomes available withing the message validity period, the SMSC will forward the SMS message.

Very often an SMSC is dedicated to handle the SMS traffic of one wireless network. A network operator usually manages its own SMSC(s) and locates them inside its wireless network system. However, it is possible for a network operator to use a third-party SMSC that is located outside the wireless network system.

You must know the address of the wireless network operator's SMSC in order to use SMS messaging with your mobile phone. Typically an SMSC address is an ordinary phone number in the international format. A mobile phone should have a menu option that can be used to configure the SMSC address. Normally, the SMSC address is pre-set in the SIM card by the wireless network operator, which means you do not need to make any changes to it. A list of SMSC numbers can be found in Appendix G - SMSC settings.

Can I operate my own SMSC?

Yes you can.

To setup an SMSC you need a computer that is connected to the mobile network. On this computer you need appropriate software, that will provide the SMSC functionality.

Private SMSCs are usually used by 3rd party SMS service providers. These providers connect to the mobile network through an IP SMS connection, such an SMPP SMS connection, an UCP SMS connection or a CIMD2 SMS connection, and they provide an SMS service to their clients over various

SMS APIs. For example the Ozeki NG SMS Gateway can be used as an SMSC to provide SMS service through the SMPP protocol to any client over the Internet. It can also provide HTTP SMS API, C# SMS API, PHP SMS support, etc.

Do I have to pay for SMS messages if I operate my own SMSC?


SMS message routed to the mobile network from your SMSC will have a cost. You will pay this cost on a per message basis to the mobile network operator or to the SMS service provider that allows you to connect your system to the mobile network.

If you want to send SMS messages to mobile phones from your SMSC, you need a way to connect to the mobile network, and you cannot do it without signing up for the service of a mobile network operator or an SMS service provider.

Can I connect to the SMSC of a mobile network operator (MNO)?


If you have Ozeki NG SMS Gateway installed, you can connect to the SMSC of a mobile network operator over the Internet (or a leased line) using an IP SMS connection, such as an SMPP, UCP or CIMD2 connection. To be able to connect you need to sign an agreement with the mobile network operator and you will have to pay for SMS messages you send through their SMSC.

Can I connect to the SMSC of a mobile network operator through SS7?

SS7 is the signaling protocol inside a mobile network. It is used in the SMS delivery between the SMSC, the HLR, and the mobile terminal. It is usually used over E1 ISDN lines, but it can also go through IP. The IP version of SS7 is called SIGTRAN.

Ozeki NG SMS Gateway does not implement the SS7 signaling protocol. To connect to the SMSC, you need to use an IP SMS protocol.

Is there anyway using any ozeki product to do HLR Lookup to see if numbers exist before sending text?

HLR lookup would be possible if the SS7 protocol would be implemented in Ozeki NG SMS Gateway. Since this protocol is not implemented, doing an HLR lookup is not possible. Even if the SS7 protocol would be implemented there is a good chance, that the mobile network operator would not let you connect to their HLR to do such lookups.

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