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2 SPDX-FileCopyrightText: © 2020 Open Networking Foundation <support@opennetworking.org>
3 SPDX-License-Identifier: Apache-2.0
4
ajayb5ad6db2021-12-09 15:23:24 -08005SD-Core as a Cloud Managed Service
6==================================
ajay60fd69f2021-11-23 22:38:10 -08007
ajayb3f40982021-12-08 14:26:11 -08008 * SD-Core is a flexible, agile, scalable and configurable dual-mode 4G/5G core
9 network platform that builds upon and enhances ONFs OMEC and free 5GC core
10 network platforms to support LTE, 5G NSA and 5G SA services.
11
12 * The SD-Core control plane provides the flexibility of simultaneous supports
13 for 5G standalone, 5G non-standalone and 4G/LTE deployments.
14
15 * SD-Core provides a rich set of APIs to Runtime Operation Control (ROC).
16
ajayb5ad6db2021-12-09 15:23:24 -080017 * Operators can use these APIs to provision the subscribers in the mobile core
18 and their associated access and connectivity policies.
19 * Control runtime configuration of network functions e.g. management of Network slices
20 * ROC includes built-in adapters for SD-Core to translate its monitoring and configuration
21 APIs to customer and operator portals as well as third-party applications with corresponding
22 levels of abstraction. Third party applications can leverage telemetry data to create
23 applications for closed loop control.
ajayb3f40982021-12-08 14:26:11 -080024
25.. image:: ../_static/images/SD-Core-Architecture.png
26 :width: 700px
27
ajayb5ad6db2021-12-09 15:23:24 -080028SD-Core Architecture
29--------------------
30SD-Core architecture enables the following distinct features:
31
32 - All SD-Core components follow 3GPP standards to interface with others as well as the
33 external networks and systems (e.g., RAN, communication services, etc.). As such,
34 components can be consumed independently and be used as part of a multi-vendor
35 mobile core deployment.
36 - SD-Cores 5G core control plane functions leverage seed code from the free5GC project,
37 upon which the SD-Core community has implemented numerous architectural changes that
38 are integrated and optimized with SD-Cores set of UPF solutions along with several
39 new features
40 - The solution enables 4G, 5G Standalone (SA) and 5G Non-Standalone (NSA) connectivity.
41 - The architecture is fully disaggregated, composed of containerized components. Helm charts are
42 provided to deploy SD-Core on K8s cluster.
43 - The platform is configurable in runtime via an extensible set of APIs.
44 - The solution is consumable as a cloud-managed service.
45 - All interfaces are designed to be robust in order to handle all network errors including but
46 not limited to packet loss, peer network function failure, and duplicate packets.
47 - SD-Cores 4G Core is designed to have a CUPS (Control-User Plane Separation) compliant architecture and
48 uses the 3GPP Packet Forwarding Control Protocol (PFCP) to implement CUPS
49 - SD-Cores 4G control plane has been enhanced to provide functional support for 5G Nonstandalone
50 operation with compliant eNBs and gNBs as per 3GPP specifications. 5G NSA related enhancements
51 include support of the extended bearer rates on required interfaces as well as the 5G NSA attributes
52 in the HSS.
53
54.. image:: ../_static/images/Sd-Core-NFs.png
55 :width: 700px
56
ajayb3f40982021-12-08 14:26:11 -080057Multiple Distributed User Planes
58--------------------------------
59
ajayb5ad6db2021-12-09 15:23:24 -080060SD-Core has two User Plane Functions (UPFs) designed to be deployed throughout
ajayb3f40982021-12-08 14:26:11 -080061the network edge. Each UPF is optimized to handle specific classes of application
62and take advantage of various hardware acceleration options. Deployments can
63intermix the UPF variants.
64
65 * P4-Based UPF optimized for private enterprise deployments, and providing fine-grained
66 visibility for verifiable performance and secure operations
67 * Containerized Dual-Core UPF optimized for private enterprise deployments, capable of
68 processing LTE and 5G traffic simultaneously
ajayb3f40982021-12-08 14:26:11 -080069
70
ajayb5ad6db2021-12-09 15:23:24 -080071In SD-Core, a connected device is assigned to a UPF based on the network-wide slice configuration.
72Specifically, in 5G core, the SMF uses the network slice information received in the user session
73context as well as the Data Network Name (DNN) information received from AMF to select the serving
74UPF. In the case of 4G core, the SPGW-C uses the the Access Point Name (APN) information to select
75the serving UPF.
ajayb3f40982021-12-08 14:26:11 -080076
ajayb5ad6db2021-12-09 15:23:24 -080077Network Slicing
78---------------
ajayb3f40982021-12-08 14:26:11 -080079
ajayb5ad6db2021-12-09 15:23:24 -080080Network slicing is one of the most important features of the 5G core network. Network
81slicing helps in isolating the network for various business and use cases. In the disaggregated
82service-based architecture of 5G core, this isolation may include only the UPF or also a subset
83of the control plane services such as the SMF. However, mobile core control functions that
84are responsible for managing user mobility, user authentication, and network slicing need
85to remain centralized across all slices. SD-Core provides the necessary APIs to manage
86network slices using external agents. ONFs ROC, pre-integrated with SD-Core, allows for this
87central management via portals as well as automation. If the management requires
88instantiation of a new UPF and/or a new SMF instance, ROC oversees this by interacting with
89edge cloud or hyperscale container management services to provision such new network
90function instances.
91
92Once all mobile core service instances are provisioned for a new slice, ROC uses SD-Core
93APIs to configure the slice as well as all required central network functions. SD-Core provides
94APIs to create and configure network slices and assign resources to each slice. Operators can
95assign a slice for a group of users/devices based on the use case. The behavior of each slice
96is configurable and can be dynamically changed during run time. SD-Cores architecture
97supports assigning dedicated network functions to a specific slice or providing logical
98separation if network functions are to be shared among various slices. Various QoS and
99access policies can be applied to each slice to control the assigned resources as well as IP
100connectivity and access control within each slice.
101Operators can create new slices based on criteria such as isolating devices allowed to access
102specific packet data networks/edge applications or keeping all devices or flows with the
103same QoS classification grouped under one slice. Network slice selection is achieved through
1043GPP-specified network functions like Network Slice Selection Function (NSSF) and Network
105Repository Function (NRF). NSSF helps in mapping the device/flow to a specific slice and
106steering the device/flow traffic to the right set of core network elements. SD-Cores 5G
107implementation natively includes both NSSF and NRF for slice selection.
108As described earlier, SD-Cores P4-based dual-core UPF allows for the monitoring of all
1094G/5G traffic with fine-grained granularity using INT. This effectively means that with the P4-
110based dual-core UPF, it is possible to conduct per packet network monitoring to track
111whether slice-specific SLAs are being met and automatically adapt network behavior by
112changing per slice resource allocations, QoS priorities etc., to automatically sustain the
113required network performance using closed-loop control.
114
115SD-Core Deployment Options
116--------------------------
117
118The level of disaggregation and associated optimizations achieved for each component of
119its 4G and 5G control plane makes SD-Core suitable for a wide variety of deployment
120options. These optimizations include the capability for the 4G and 5G control planes to
121oversee many UPFs, potentially instantiated at geographically diverse locations, as illustrated
122It is possible to deploy all components of SD-Core collocated in an edge cloud or a central
123cloud for private consumption. It is also possible to distribute the components of SD-Core
124across multiple clouds, edge and central, to deliver a cloud-managed multi-tenant
125connectivity service. In this distributed deployment option, SD-Cores control plane will run
126on a central/hyperscaler cloud and control multiple user planes running on different onpremises
127edge clouds, potentially serving distinct customers as illustrated in Figure 8. In this
128deployment, the 4G and 5G control plane functions can scale as necessary. Each customer
129site can have more than one UPF deployed depending on the use cases and network slices
130configured. Operators can also decide to deploy UPFs in the central cloud for certain
131customers and their use cases where latency and data privacy is not a concern. SD-Core
132brings the flexibility to define network slices for each customer in such a way that one
133deploys a distinct UPF for each slice and instantiates the various components of the solution
134at the customer edge or in the central cloud, as needed and best suited.
135
136
137.. image:: ../_static/images/hybrid-cloud.png
138 :width: 700px
139
140SD-Cores hybrid cloud deployment is an important enabler for a managed 4G/5G
141connectivity service where each customer site may be deployed to serve a different set of
142use cases and may have different types of underlying cloud environments. The 4G/5G core
143control planes running on the central cloud have been designed and optimized to support
144distributed edge sites which are spread across different locations across the world. The
145SD-Core control plane uses PFCP to communicate with the UPFs at the edge sites. The hybrid
146cloud deployment architecture has been optimized to handle variability in encountered
147delays communicating with the remote edge sites and is equipped to handle potential
148packet losses and retransmissions to support a multi-tenant, distributed geography
149deployment.
150
151
ajay60fd69f2021-11-23 22:38:10 -0800152
153Architecture Diagram of SD-Core 4G block
154----------------------------------------
ajayb5ad6db2021-12-09 15:23:24 -0800155- show configPod, config distribution, Cassandra DB, SIMApp, 4G network Functions
ajay60fd69f2021-11-23 22:38:10 -0800156
157Architecture Diagram of SD-Core 5G block
158----------------------------------------
159- show configPod, config distribution, MongoDB, SIMApp, 5G network functions
160
161Configuration Distribution Architecture
162---------------------------------------
163- how grpc, rest is used to distribute the configuration
164