Service Communication Proxy (SCP)

The BroadForward Service Communication Proxy (SCP) plays an important role within the 5G Service Based Architecture (SBA), providing functions ranging from simplifying network topology by applying signaling aggregation and routing, to load balancing, overload handling and message parameter harmonization as well as interworking with legacy systems.

The role of the Service Communication Proxy
The SCP is a new HTTP/2 based network function enabling dynamic scaling and management of communication and services in the 5G network. The SCP has a role which in some ways can be compared with its predecessors, such as the Signaling Transfer Point (STP), the central signaling router used in 2G/3G to route SS7 signaling messages, as well at the Diameter Signaling Controller (DSC) doing the same for Diameter messages in 4G. A key difference with these legacy routers is that the SCP can be responsible to resolve Network Function (NF) discovery requests via communication with the Network Repository Function (NRF), and can initiate Domain Name Server (DNS A-record) IP address lookups to a DNS to locate every live instance for every available Network Function.

BroadForward SCP
The BroadForward SCP simplifies network topology by applying signaling aggregation and routing, load balancing, overload handling and message parameter harmonization. Furthermore, the BroadForward SCP performs delegated discovery and provides communication authorization and security functions. In addition, the BroadForward SCP supports combined deployment with legacy functions such as the STP and DRA-DEA and with other 5G functions like BSF and 4G-5G interworking.

Overview of the BroadForward SCP (with optional standalone or on-board BSF)
The BroadForward SCP provides a single point of entry for a cluster of a given type of Network Functions (e.g. UDR or PCF). When a network function is discovered through the NRF, the entry point to the NF cluster is the SCP. The SCP can also be configured as an exit point of traffic for a given Network Function cluster. Supporting the so-called Model-D from TS 23.501, the SCP allows for the creation of a service-based architecture (rather than a point-to-point mesh amongst hundreds of instances of network functions), supporting massive scalability and high delivery assurance. Besides centralized routing and load balancing, other benefits of Model-D are; real time delivery of NF and AF requests and responses and optimizing capacity in cases of ‘bursty’ signaling traffic.

Functions of the BroadForward SCP include:

  • Delegated NF service discovery
  • Message parameter harmonization
  • Message forwarding, routing and load balancing of HTTP service requests
  • Single entry point for a NF FQDN
  • Security, authorization of the NF consumer to access the producer
  • Maintain legacy support for 5G SA (e.g. interworking with OCS and PCRF)
  • Overload control
  • Optional UDR resolution (subscriber lookup)
  • Extendable with other BroadForward 5G network functions, such as BSF and SEPP.

Combining network functions
The BroadForward SCP runs on a unique single engine software architecture called BFX, allowing operators to combine multiple networks functions on the same platform, such as SEPP, STP, DRA and BSF. This provides many benefits, such as:

  • Reduction of integration points, and on-board capability for interworking and interoperability
  • Centralized and uniform IT integration, signaling management, configuration, provisioning, subscriber management, reporting and control
  • Centralized and uniform use of common network applications (e.g. firewall, number portability, steering of roaming)
  • Easy to operate, uniform operations across domain technologies
  • Single capacity license with free traffic mix across supported protocols

Hardware-agnostic solution, supporting cloud and containerized deployment
The BroadForward SCP runs on any off-the-shelf hardware or in a virtualized environment. It is a 100% software-based solution, supporting virtualization and cloud deployment as well as containerized application deployment. The BroadForward SCP does not rely on specialist hardware or proprietary operating systems. The ability to deploy the BroadForward SCP on a common (shared) platform supports operators and vendors in migrating away from proprietary based appliance systems to a standards based, hardware agnostic, software only, infrastructure.

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