What is SP GW combined node of S GW and P GW

Actually, in the context of 5G mobile networks, there isn't a physically combined node called "SP GW" that merges the functionalities of S Gateway (S-GW) and Packet Data Network Gateway (P-GW) entirely.

Here's a breakdown of the situation:

Traditional EPC Architecture (4G):

• In 4G (LTE) networks, the Evolved Packet Core (EPC) architecture relied on separate S-GW and P-GW entities:
  • S-GW (Serving Gateway): Responsible for user plane data traffic forwarding between the User Equipment (UE) and the Mobility Management Entity (MME) within the core network. It also manages mobility aspects like anchoring UEs during handovers.
  • P-GW (Packet Data Network Gateway): Acts as the gateway between the EPC and external packet data networks like the internet. It performs tasks like IP address allocation and packet filtering based on policies.

Evolution in 5G: Control and User Plane Separation (CUPS):

• With the introduction of 5G, a new architectural concept called Control and User Plane Separation (CUPS) has been introduced. CUPS aims to improve network flexibility, scalability, and latency.
• Under CUPS, the functionalities of S-GW and P-GW are virtualized and split into separate network functions (NFs):
  • S-GW functions: Split into two NFs:
    • UPF (User Plane Function): Handles user plane data forwarding within the core network.
    • SMF (Session Management Function): Manages mobility aspects traditionally handled by S-GW (e.g., anchoring).
  • P-GW functions: Split into two NFs:
    • UPF (User Plane Function): Similar to the UPF in S-GW, it forwards user plane data but towards the external network.
    • PCF (Policy Control Function): Handles functionalities like IP address allocation and packet filtering previously performed by P-GW.

Terminology Confusion:

• Some vendors might use the term "xGW" to represent a single physical node that can host these virtualized NFs (e.g., S-GW functionalities as UPF and SMF). However, it's not a merged entity like a traditional S-GW or P-GW. It's still a separation of functionalities at the logical level (NFs) running on a common hardware platform.

Key Points:

• In 5G with CUPS, S-GW and P-GW functionalities are not directly combined but rather separated into virtualized NFs.
• These NFs (UPF, SMF, PCF) can be deployed on a common physical infrastructure, leading to potential confusion with terminology like "xGW".
• The separation allows for more flexible deployment and network slicing based on specific service requirements.

By understanding the evolution from traditional EPC architecture to CUPS with NF separation, you can avoid confusion regarding the terminology and grasp the underlying concepts of user and control plane separation in 5G networks.