Positioning of the Services Control Gateway
The positioning of the Services Delivery Gateway (SDG) for infrastructure services remains unaltered from the placement of the routers that run Services Control Gateway for other services features. VASs can be delivered in many ways and by different elements. This behavior is normally determined by scaling and operational requirements. It shows some typical combinations between VAS aspects, other users of DPI technology (for example, analytics) and typical PE functions. Although typically separate (mostly due to operational aspects), PE functions can coexist with the VAS functions. The SDG as an analytics data source requires not only the NE inspection capabilities, but also scaling to be on the same level as DPI NEs; the analysis layer is also included in such a setup. This functionality is not currently supported. The SDG as a TDF (for VAS delivery) can be positioned in any of the following roles. Depending on the customer network, it can perform multiple rules simultaneously:
Service orchestration—NE responsible for controlling the flow of traffic amongst the various VASs. It also includes the functionality of server load balancing (SLB) towards mainly HTTP servers and proxies. Per-subscriber service chaining with application awareness is the key feature.
Specific VAS—NE responsible for delivering a particular VAS (for example, parental control, HTTP header enrichment). Per-subscriber service-chaining with application awareness (typically URL-based) is the key feature.
Fixed mobile convergence (FMC) delivery—NE responsible for PCC enforcement for subscribers from multiple access technologies. Per subscriber control with application awareness is the key feature.
The TDF delivers sophisticated monetization use cases interfacing with all the key elements of an EPC, namely the PCC and the GGSN/PGW, on exactly the same platform used to deliver MobileNext EPC. Therefore, it enables packet core capabilities to be configured and managed in an effective, comprehensive manner.