When a call is made to a ring back subscriber, you have to send the so-called A leg to a platform that plays the right ring back tone while your switch is setting up the B leg to the subscriber. As soon as the subscriber answers, you want to take the call back from the platform and connect the A and B legs.
Today, most networks are heterogeneous, including legacy fixed-line and mobile switches as well as new next-generation switches, all from various different vendors. In next-generation networks, we perform the entire leg management using the SIP protocol.
Most legacy mobile switches have a built-in feature that allows them to perform the leg management.
The challenges start when you have legacy mobile or fixed line switches without this feature. In such cases, you could use an intelligent network with INAP CS2 or a proprietary variant, such as Ericsson CS1+. In some fixed line networks, you can even use a special ISDN feature to perform the leg management, the 2 B-channel transfer.
Regardless of the peculiarities of your network, we know how to get leg management to work and have the necessary call flows and protocols off-the-shelf. Contact us to learn more about leg management.