overview/architecture.rst - sdcore-docs - Gitiles

 ..
    SPDX-FileCopyrightText: © 2020 Open Networking Foundation <support@opennetworking.org>
    SPDX-License-Identifier: Apache-2.0

 SD-Core as a Cloud Managed Service
 ==================================

     * SD-Core is a flexible, agile, scalable and configurable dual-mode 4G/5G core
       network platform that builds upon and enhances ONF’s OMEC and free 5GC core
       network platforms to support LTE, 5G NSA and 5G SA services.

     * The SD-Core control plane provides the flexibility of simultaneous supports
       for 5G standalone, 5G non-standalone and 4G/LTE deployments.

     * SD-Core provides a rich set of APIs to Runtime Operation Control (ROC).

         * Operators can use these APIs to provision the subscribers in the mobile core
           and their associated access and connectivity policies.
         * Control runtime configuration of network functions e.g. management of Network slices
         * ROC includes built-in adapters for SD-Core to translate its monitoring and configuration
           APIs to customer and operator portals as well as third-party applications with corresponding
           levels of abstraction. Third party applications can leverage telemetry data to create
           applications for closed loop control.

 .. image:: ../_static/images/SD-Core-Architecture.png
   :width: 700px

 SD-Core Architecture
 --------------------
 SD-Core architecture enables the following distinct features:

     - All SD-Core components follow 3GPP standards to interface with others as well as the
       external networks and systems (e.g., RAN, communication services, etc.). As such,
       components can be consumed independently and be used as part of a multi-vendor
       mobile core deployment.
     - SD-Core’s 5G core control plane functions leverage seed code from the free5GC project,
       upon which the SD-Core community has implemented numerous architectural changes that
       are integrated and optimized with SD-Core’s set of UPF solutions along with several
       new features
     - The solution enables 4G, 5G Standalone (SA) and 5G Non-Standalone (NSA) connectivity.
     - The architecture is fully disaggregated, composed of containerized components. Helm charts are
       provided to deploy SD-Core on K8s cluster.
     - The platform is configurable in runtime via an extensible set of APIs.
     - The solution is consumable as a cloud-managed service.
     - All interfaces are designed to be robust in order to handle all network errors including but
       not limited to packet loss, peer network function failure, and duplicate packets.
     - SD-Core’s 4G Core is designed to have a CUPS (Control-User Plane Separation) compliant architecture and
       uses the 3GPP Packet Forwarding Control Protocol (PFCP) to implement CUPS
     - SD-Core’s 4G control plane has been enhanced to provide functional support for 5G Nonstandalone
       operation with compliant eNBs and gNBs as per 3GPP specifications. 5G NSA related enhancements
       include support of the extended bearer rates on required interfaces as well as the 5G NSA attributes
       in the HSS.

 .. image:: ../_static/images/Sd-Core-NFs.png
   :width: 700px

 Multiple Distributed User Planes
 --------------------------------

 SD-Core has two User Plane Functions (UPFs) designed to be deployed throughout
 the network edge. Each UPF is optimized to handle specific classes of application
 and take advantage of various hardware acceleration options. Deployments can
 intermix the UPF variants.

     * P4-Based UPF optimized for private enterprise deployments, and providing fine-grained
       visibility for verifiable performance and secure operations
     * Containerized Dual-Core UPF optimized for private enterprise deployments, capable of
       processing LTE and 5G traffic simultaneously


 In SD-Core, a connected device is assigned to a UPF based on the network-wide slice configuration.
 Specifically, in 5G core, the SMF uses the network slice information received in the user session
 context as well as the Data Network Name (DNN) information received from AMF to select the serving
 UPF. In the case of 4G core, the SPGW-C uses the the Access Point Name (APN) information to select
 the serving UPF.

 Network Slicing
 ---------------

 Network slicing is one of the most important features of the 5G core network. Network
 slicing helps in isolating the network for various business and use cases. In the disaggregated
 service-based architecture of 5G core, this isolation may include only the UPF or also a subset
 of the control plane services such as the SMF. However, mobile core control functions that
 are responsible for managing user mobility, user authentication, and network slicing need
 to remain centralized across all slices. SD-Core provides the necessary APIs to manage
 network slices using external agents. ONF’s ROC, pre-integrated with SD-Core, allows for this
 central management via portals as well as automation. If the management requires
 instantiation of a new UPF and/or a new SMF instance, ROC oversees this by interacting with
 edge cloud or hyperscale container management services to provision such new network
 function instances.

 Once all mobile core service instances are provisioned for a new slice, ROC uses SD-Core
 APIs to configure the slice as well as all required central network functions. SD-Core provides
 APIs to create and configure network slices and assign resources to each slice. Operators can
 assign a slice for a group of users/devices based on the use case. The behavior of each slice
 is configurable and can be dynamically changed during run time. SD-Core’s architecture
 supports assigning dedicated network functions to a specific slice or providing logical
 separation if network functions are to be shared among various slices. Various QoS and
 access policies can be applied to each slice to control the assigned resources as well as IP
 connectivity and access control within each slice.
 Operators can create new slices based on criteria such as isolating devices allowed to access
 specific packet data networks/edge applications or keeping all devices or flows with the
 same QoS classification grouped under one slice. Network slice selection is achieved through
 3GPP-specified network functions like Network Slice Selection Function (NSSF) and Network
 Repository Function (NRF). NSSF helps in mapping the device/flow to a specific slice and
 steering the device/flow traffic to the right set of core network elements. SD-Core’s 5G
 implementation natively includes both NSSF and NRF for slice selection.
 As described earlier, SD-Core’s P4-based dual-core UPF allows for the monitoring of all
 4G/5G traffic with fine-grained granularity using INT. This effectively means that with the P4-
 based dual-core UPF, it is possible to conduct per packet network monitoring to track
 whether slice-specific SLAs are being met and automatically adapt network behavior by
 changing per slice resource allocations, QoS priorities etc., to automatically sustain the
 required network performance using closed-loop control.

 SD-Core Deployment Options
 --------------------------

 The level of disaggregation and associated optimizations achieved for each component of
 its 4G and 5G control plane makes SD-Core suitable for a wide variety of deployment
 options. These optimizations include the capability for the 4G and 5G control planes to
 oversee many UPFs, potentially instantiated at geographically diverse locations, as illustrated
 It is possible to deploy all components of SD-Core collocated in an edge cloud or a central
 cloud for private consumption. It is also possible to distribute the components of SD-Core
 across multiple clouds, edge and central, to deliver a cloud-managed multi-tenant
 connectivity service. In this distributed deployment option, SD-Core’s control plane will run
 on a central/hyperscaler cloud and control multiple user planes running on different onpremises
 edge clouds, potentially serving distinct customers as illustrated in Figure 8. In this
 deployment, the 4G and 5G control plane functions can scale as necessary. Each customer
 site can have more than one UPF deployed depending on the use cases and network slices
 configured. Operators can also decide to deploy UPFs in the central cloud for certain
 customers and their use cases where latency and data privacy is not a concern. SD-Core
 brings the flexibility to define network slices for each customer in such a way that one
 deploys a distinct UPF for each slice and instantiates the various components of the solution
 at the customer edge or in the central cloud, as needed and best suited.


 .. image:: ../_static/images/hybrid-cloud.png
   :width: 700px

 SD-Core’s hybrid cloud deployment is an important enabler for a managed 4G/5G
 connectivity service where each customer site may be deployed to serve a different set of
 use cases and may have different types of underlying cloud environments. The 4G/5G core
 control planes running on the central cloud have been designed and optimized to support
 distributed edge sites which are spread across different locations across the world. The
 SD-Core control plane uses PFCP to communicate with the UPFs at the edge sites. The hybrid
 cloud deployment architecture has been optimized to handle variability in encountered
 delays communicating with the remote edge sites and is equipped to handle potential
 packet losses and retransmissions to support a multi-tenant, distributed geography
 deployment.
	..
	SPDX-FileCopyrightText: © 2020 Open Networking Foundation <support@opennetworking.org>
	SPDX-License-Identifier: Apache-2.0

	SD-Core as a Cloud Managed Service
	==================================

	* SD-Core is a flexible, agile, scalable and configurable dual-mode 4G/5G core
	network platform that builds upon and enhances ONF’s OMEC and free 5GC core
	network platforms to support LTE, 5G NSA and 5G SA services.

	* The SD-Core control plane provides the flexibility of simultaneous supports
	for 5G standalone, 5G non-standalone and 4G/LTE deployments.

	* SD-Core provides a rich set of APIs to Runtime Operation Control (ROC).

	* Operators can use these APIs to provision the subscribers in the mobile core
	and their associated access and connectivity policies.
	* Control runtime configuration of network functions e.g. management of Network slices
	* ROC includes built-in adapters for SD-Core to translate its monitoring and configuration
	APIs to customer and operator portals as well as third-party applications with corresponding
	levels of abstraction. Third party applications can leverage telemetry data to create
	applications for closed loop control.

	.. image:: ../_static/images/SD-Core-Architecture.png
	:width: 700px

	SD-Core Architecture
	--------------------
	SD-Core architecture enables the following distinct features:

	- All SD-Core components follow 3GPP standards to interface with others as well as the
	external networks and systems (e.g., RAN, communication services, etc.). As such,
	components can be consumed independently and be used as part of a multi-vendor
	mobile core deployment.
	- SD-Core’s 5G core control plane functions leverage seed code from the free5GC project,
	upon which the SD-Core community has implemented numerous architectural changes that
	are integrated and optimized with SD-Core’s set of UPF solutions along with several
	new features
	- The solution enables 4G, 5G Standalone (SA) and 5G Non-Standalone (NSA) connectivity.
	- The architecture is fully disaggregated, composed of containerized components. Helm charts are
	provided to deploy SD-Core on K8s cluster.
	- The platform is configurable in runtime via an extensible set of APIs.
	- The solution is consumable as a cloud-managed service.
	- All interfaces are designed to be robust in order to handle all network errors including but
	not limited to packet loss, peer network function failure, and duplicate packets.
	- SD-Core’s 4G Core is designed to have a CUPS (Control-User Plane Separation) compliant architecture and
	uses the 3GPP Packet Forwarding Control Protocol (PFCP) to implement CUPS
	- SD-Core’s 4G control plane has been enhanced to provide functional support for 5G Nonstandalone
	operation with compliant eNBs and gNBs as per 3GPP specifications. 5G NSA related enhancements
	include support of the extended bearer rates on required interfaces as well as the 5G NSA attributes
	in the HSS.

	.. image:: ../_static/images/Sd-Core-NFs.png
	:width: 700px

	Multiple Distributed User Planes
	--------------------------------

	SD-Core has two User Plane Functions (UPFs) designed to be deployed throughout
	the network edge. Each UPF is optimized to handle specific classes of application
	and take advantage of various hardware acceleration options. Deployments can
	intermix the UPF variants.

	* P4-Based UPF optimized for private enterprise deployments, and providing fine-grained
	visibility for verifiable performance and secure operations
	* Containerized Dual-Core UPF optimized for private enterprise deployments, capable of
	processing LTE and 5G traffic simultaneously


	In SD-Core, a connected device is assigned to a UPF based on the network-wide slice configuration.
	Specifically, in 5G core, the SMF uses the network slice information received in the user session
	context as well as the Data Network Name (DNN) information received from AMF to select the serving
	UPF. In the case of 4G core, the SPGW-C uses the the Access Point Name (APN) information to select
	the serving UPF.

	Network Slicing
	---------------

	Network slicing is one of the most important features of the 5G core network. Network
	slicing helps in isolating the network for various business and use cases. In the disaggregated
	service-based architecture of 5G core, this isolation may include only the UPF or also a subset
	of the control plane services such as the SMF. However, mobile core control functions that
	are responsible for managing user mobility, user authentication, and network slicing need
	to remain centralized across all slices. SD-Core provides the necessary APIs to manage
	network slices using external agents. ONF’s ROC, pre-integrated with SD-Core, allows for this
	central management via portals as well as automation. If the management requires
	instantiation of a new UPF and/or a new SMF instance, ROC oversees this by interacting with
	edge cloud or hyperscale container management services to provision such new network
	function instances.

	Once all mobile core service instances are provisioned for a new slice, ROC uses SD-Core
	APIs to configure the slice as well as all required central network functions. SD-Core provides
	APIs to create and configure network slices and assign resources to each slice. Operators can
	assign a slice for a group of users/devices based on the use case. The behavior of each slice
	is configurable and can be dynamically changed during run time. SD-Core’s architecture
	supports assigning dedicated network functions to a specific slice or providing logical
	separation if network functions are to be shared among various slices. Various QoS and
	access policies can be applied to each slice to control the assigned resources as well as IP
	connectivity and access control within each slice.
	Operators can create new slices based on criteria such as isolating devices allowed to access
	specific packet data networks/edge applications or keeping all devices or flows with the
	same QoS classification grouped under one slice. Network slice selection is achieved through
	3GPP-specified network functions like Network Slice Selection Function (NSSF) and Network
	Repository Function (NRF). NSSF helps in mapping the device/flow to a specific slice and
	steering the device/flow traffic to the right set of core network elements. SD-Core’s 5G
	implementation natively includes both NSSF and NRF for slice selection.
	As described earlier, SD-Core’s P4-based dual-core UPF allows for the monitoring of all
	4G/5G traffic with fine-grained granularity using INT. This effectively means that with the P4-
	based dual-core UPF, it is possible to conduct per packet network monitoring to track
	whether slice-specific SLAs are being met and automatically adapt network behavior by
	changing per slice resource allocations, QoS priorities etc., to automatically sustain the
	required network performance using closed-loop control.

	SD-Core Deployment Options
	--------------------------

	The level of disaggregation and associated optimizations achieved for each component of
	its 4G and 5G control plane makes SD-Core suitable for a wide variety of deployment
	options. These optimizations include the capability for the 4G and 5G control planes to
	oversee many UPFs, potentially instantiated at geographically diverse locations, as illustrated
	It is possible to deploy all components of SD-Core collocated in an edge cloud or a central
	cloud for private consumption. It is also possible to distribute the components of SD-Core
	across multiple clouds, edge and central, to deliver a cloud-managed multi-tenant
	connectivity service. In this distributed deployment option, SD-Core’s control plane will run
	on a central/hyperscaler cloud and control multiple user planes running on different onpremises
	edge clouds, potentially serving distinct customers as illustrated in Figure 8. In this
	deployment, the 4G and 5G control plane functions can scale as necessary. Each customer
	site can have more than one UPF deployed depending on the use cases and network slices
	configured. Operators can also decide to deploy UPFs in the central cloud for certain
	customers and their use cases where latency and data privacy is not a concern. SD-Core
	brings the flexibility to define network slices for each customer in such a way that one
	deploys a distinct UPF for each slice and instantiates the various components of the solution
	at the customer edge or in the central cloud, as needed and best suited.


	.. image:: ../_static/images/hybrid-cloud.png
	:width: 700px

	SD-Core’s hybrid cloud deployment is an important enabler for a managed 4G/5G
	connectivity service where each customer site may be deployed to serve a different set of
	use cases and may have different types of underlying cloud environments. The 4G/5G core
	control planes running on the central cloud have been designed and optimized to support
	distributed edge sites which are spread across different locations across the world. The
	SD-Core control plane uses PFCP to communicate with the UPFs at the edge sites. The hybrid
	cloud deployment architecture has been optimized to handle variability in encountered
	delays communicating with the remote edge sites and is equipped to handle potential
	packet losses and retransmissions to support a multi-tenant, distributed geography
	deployment.