HTTP/2 Signaling Network for the 5GC

Course outline : The 5G SA network introduces the need for a new signaling protocol used by the network functions of the control plane of the 5G core network, namely HTTP2 (HyperText Transfer Protocol version 2). As with the 2G/3G core networks which use an SS7/SIGTRAN signaling network and the 4G core network which relies on DIAMETER signaling network, the 5G core network uses an HTTP2/JSON signaling network with signaling routers called SCP (Service Communication Proxy) for internal HTTP/2 routing in a mobile network and SEPP (Security Edge Protection Proxy) for routing between a mobile network and external networks in the context of roaming. HTTP/2 inherits from the HTTP/1.1 protocol particulary, its methods, its status codes, its headers but improves various aspects of the HTTP/1.1 protocol such as the transition from a text protocol to a binary protocol, the multiplexing on the same TCP connection of a large number of HTTP requests/responses with the prioritization of HTTP streams, the compression of HTTP headers with the HPACK method, the Server Push mechanism, etc. The exchange of data in the payloads of HTTP requests and responses is carried out in JSON (JavaScript Object Notation) format. The purpose of this training is to present:
• The HTTP/1.1 protocol to understand the HTTP/2 protocol,
• Optimizations provided by the HTTP/2 protocol,
• The 5G core network and in particular the control plane network functions which contribute to the routing of HTTP2 signaling, in particular, NRF, BSF, NSSF, SCP and SEPP, IPX HTTP Proxy as well as their service interfaces.
• HTTP/2 signaling routing in the context of 5GC.

1.5GC Architecture
1.1. 5GC Control Plane
1.1.1. Control plane network functions
1.1.2. Common network functions
1.1.3. Network slice-specific network functions
1.1.4. Service-Based Control Plane Architecture
1.1.5. service-based interface
1.1.5.1. NF service
1.1.5.2. service operation
1.1.6. Control plane network functions contributing to HTTP2 traffic routing: NSSF, NRF, BSF, SCP, SEPP, IPX HTTP Proxy
1.2. 5GC user identities

2. HTTP2 protocol
2.1. HTTP/1.1 Protocol: Methods, Status Code, Headers
2.2. HTTP/2 Principles: Message, Frame and Stream
2.3. The binary format
2.4. Stream multiplexing
2.5. Priorities and dependencies
2.6. Header compression: HPACK
2.6.1. Static table
2.6.2. Dynamic table
2.6.3. Huffman encoding
2.7. Server push
2.8. HTTP2 and TLS
2.9. JSON

3. REST APIs
3.1. REST Principles
3.2. REST Constraints
3.3. Examples of service APIs in the 5GC context related to routing functions
3.4. NRF Service API
3.5. BSF Service API
3.6. NSSF Service API

4. HTTP2 Signaling Network Architecture
4.1. Communication options
4.1.1. Direct communication with and without interaction with NRF
4.1.2. Indirect communication with and without discovery delegation
4.2. SCP (Service Communication Proxy) entity for internal HTTP2 signaling network within a mobile network
4.3. SEPP (Security Edge Protection Proxy) entity for HTTP2 signaling routing between a mobile network and external networks (in the context of roaming)
4.4. NRF network function for routing information
4.5. SCP network function: Routing, load sharing and congestion control
4.6. Additional SEPP functions: Topology masking and firewalling
4.7. BSF network function and session binding
4.8. SCP/SEPP/SBF and DIAMETER Agent (DEA/DRA) combined for 5GC/EPC interworking

5. 5GS procedures with HTTP/2
5.1. Registration/Deregistration
5.2. Location update
5.3. PDU session establishment
5.4. Service request
5.5. SMS delivery and reception

6. N1 NAS Protocol
6.1. NAS identities
6.2. NAS MM, NAS SM, NAS SMS
6.3. NAS Security
6.4. N1 NAS MM
6.5. N1 NAS SM
6.6. N1 NAS SMS