Customer SMPP accounts are associated with a **service**, and it is the **routing profile** for the service that defines the routing of customer messages. Messages are either routed based on [Scripts](doc:scripts) or **SMSCs** defined in **SMSC groups**.

A service’s **routing profile** contains one or more groupings of SMSCs (an **SMSC group**). These SMSC groups are normally used to group together one or more **SMSC** accounts from an individual supplier and belong to a specific service from that supplier.

Relationship between service, routing profile, SMSC group and SMSCs.

A number of different routing methods are being added to the SMPP SMS Gateway. The following routing strategies are currently available. The strategy for a **routing profile** can be selected in the Routing section. | Used in routing decision | RR | Net-RR | | --------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------- | | | Uses all SMSCs in all SMSC groups that are part of routing profile. Uses SMSCs in a round-robin distribution. | Same as for RR, but only uses SMSCs that can reach destination network. | | Network coverage (**Suppliers > Routes**) | No | Yes | | Cost for sending message to network via SMSC (**Suppliers > Routes**) | No | No | # SMSC Selection when using RR and Net-RR routing strategies