In the traditional real-time communication, voice sessions have a one-to-one relationship between signaling and media, either with or without transcoding. The service provider defines the application that runs on the device; hence, network element, gateway, or SBC requires single dimensional scaling.
An Integrated Signaling and Media network element (I-SBC) scales horizontally and runs on a custom hardware to provide the required scaling and capacity. The I-SBCs dominates the network traffic in service provider networks. The SBC hardware series is designed to process and transcode more calls, utilizing all the available media resources. But as services evolve to support multimedia, the change in traffic turns out to be more dynamic.
As the traditional communication has one session for every media (S1:M1) relation with or without transcoding; the next generation communication has one session with no media (S1:M0), or one session with multiple media (S1:Mn) relation with or without transcoding. Due to this dynamic relation, the next generation communication service requires the following three planes:
Signaling plane: for more IM presence status
Media plane: for video, MSRP, multiple streams per session
Transcoding plane: for transcoding / transrating / transizing of audio or video
The services offered by an I-SBC into individual functions that can scale based on traffic needs. The implementation of distributed functions in the network infrastructure provides SBC applications the ability to distribute more functionalities throughout the network and to utilize network effectively.
The advantages of decomposing include:
Example: Signaling component scales if the traffic requires high signaling such as presence without the media component. Similarly, traffic with high media requirements like video calls, instantiates more instances in the media cluster. Traffic that needs high transcoding requires instantiating more instances in the transcoding cluster.
The D-SBC uses the required Sonus network elements. The SBC function is considered as a cluster providing a specific service:
These clusters coordinate with each other and are linked by S-SBC using the Sonus Media Control protocol on a per-call basis to provide SBC as a service.
A cluster is a single application consisting of multiple discrete compute elements such as VMs. A cluster includes one application, such as S-SBC or M-SBC, with multiple nodes providing a specific service. The Cloud environment supports multiple clusters simultaneously but with limited capacity. The Cloud service uses one or more cluster applications each running one or more nodes providing a specific service. The D-SBC architecture breaks all the services into separate functions known as clusters (S-SBC cluster, M-SBC cluster and T-SBC cluster). For more information on creating D-SBC SWe clusters on the EMS, refer to Creating an SBC SWe Cluster.