SPN FGU

What Is SPN FGU?

Building upon the efficient Ethernet framework of SPN, the SPN Fine Granularity Unit (FGU) offers cost-effective, finely-tailored, and robust FGU transport channels by integrating fine-grained slicing into the SPN architecture. Specifically, the FGU enhances the granularity of hard slicing from 5 Gbit/s to 10 Mbit/s to fulfill the diverse transport needs (such as precise bandwidth granularity, strong isolation, and heightened security) of 5G vertical industry applications and dedicated line services. This advancement is poised to play a pivotal role in expediting their deployment.

Why Is SPN FGU Needed?

Today, 5G deployment is progressing rapidly, with a heightened emphasis on vertical industry applications spanning sectors such as electric power, transportation, government, and finance within the 5G ecosystem. For these vertical industries, carriers are required to establish numerous segregated virtual networks atop the shared physical network infrastructure. These virtual networks must offer varying levels of isolation and operate autonomously, with their respective lifecycles managed independently. To ensure the secure transmission of diverse services across different industries, SPN's hard-isolated slicing technology can be leveraged.

As 5G vertical industry applications transition from singular scenarios to systematic and intricate environments, and as computing networks gain traction, the diversity in industry user demands grows, alongside the complexity of application scenarios. Consequently, the surge in data volumes and efficient computing capabilities introduces a myriad of transport requirements, including deterministic latency, heightened security, and bandwidths of 1 Gbit/s or lower. Moreover, the proliferation of government, financial, and large enterprise private line services presents varying demands concerning the degree and granularity of slice isolation within the SPN framework.

According to findings outlined in the SPN FGU Technical White Paper presented at the OptiNet China Conference, 5G vertical industries (including computing services) and government and enterprise private lines typically require a minimum bandwidth of 2 Mbit/s, with a significant portion of services needing bandwidths of less than 10 Mbit/s. However, current slicing technologies often operate at the Gbit/s level, resulting in inefficient bandwidth utilization for services with smaller bandwidth requirements. Moreover, as the number of such services grows, the overall network bandwidth demand escalates accordingly. Given this scenario, FGU slicing, tailored to match service bandwidth requirements more closely, emerges as a preferable technology within the SPN framework.

SPN FGU incorporates fine-grained slicing into SPN architecture, delivering cost-effective, finely-tuned, and rigorously isolated FGU transport channels.

The Advantages of SPN FGU

SPN FGU builds upon the SPN technology architecture with selective enhancements made to the Slicing Packet Layer (SPL), Slicing Channel Layer (SCL), and Slicing Transport Layer (STL), as depicted in the following diagram.

• SPL: The SPL layer now includes support for the Constant Bit Rate (CBR) service type. It facilitates fine-grained mapping of CBR services based on protocols like E1 and STM-1, enabling seamless timeslot switching from ingress to egress and ensuring robust service isolation.

• SCL: The SCL layer now incorporates support for the FGU layer, offering 10 Mbit/s hard slicing for services. Positioned as an independent sublayer, the FGU layer is decoupled from the service layer and can be flexibly transported over the MTN path layer, MTN segment layer, or Ethernet physical layer as needed.

• STL: The STL layer now features support for 10GE ports catering to industry applications, alongside its existing support for SPN-defined high-speed Ethernet physical-layer interfaces such as 50GE, 100GE, 200GE, and 400GE. The Ethernet Physical Coding Sublayer (PCS) utilizes 64/66B blocks compliant with Ethernet bottom-layer protocol stack requirements, ensuring seamless compatibility between FGU and this protocol stack.

SPN hard slicing operates in a manner where it does not inspect or modify service packet data, a characteristic that FGU inherits. This allows packets to pass through FGU hard slices transparently, ensuring compatibility with packet technologies.

Furthermore, SPN FGU optimizes the utilization of existing technologies while streamlining processing mechanisms. It is suitable for various types of devices, including CPEs, hubs, access devices, aggregation devices, and core devices, facilitating end-to-end FGU deployment on operational networks. The SPN Mbit/s-granularity slicing technology enhances FGU OAM, slice timeslot, and bandwidth adjustment mechanisms, providing the following technical benefits:

• Enhanced Security: FGU channels utilize dedicated timeslots, allocated and fixed at the management and control layer, ensuring strict TDM features and hard isolation to enhance service and data security within the computing environment.

• Improved Reliability: FGU OAM, compatible with SPN/MTN path OAM, provides end-to-end monitoring for each FGU channel without user awareness of OAM insertion/extraction. Additionally, 1+1 protection for FGU channels ensures carrier-grade switching performance, even in scenarios involving device power-off or link faults.

• Predictable Latency: E2E non-blocking timeslot switching achieves nanosecond-level service jitter, ensuring consistent and stable service transmission latency.

• Seamless Slice Bandwidth Adjustment: The comprehensive timeslot and bandwidth adjustment mechanism ensures zero packet loss during adjustments to FGU slice timeslots and bandwidth, maintaining uninterrupted service delivery.

The Application of SPN FGU

5G Vertical Industry Scenario

Network slicing, as the fundamental enabler for 5G vertical industries, plays a crucial role in ensuring diverse industry-specific SLAs, service security, reliability, and both software and hardware isolation. Control services within 5G vertical industries demand networks capable of delivering low latency and high reliability, areas where SPN FGU demonstrates its significance. It is poised to be a pivotal element in expediting the deployment of 5G vertical industry applications.

Taking the electric power industry as an illustration, adhering to the power security prerequisites of "secure partitioning, dedicated networks, horizontal isolation, and vertical authentication," power grid services can be categorized into four zones based on security partitions: production control service zone (security partition I), production non-control service zone (security partition II), production management service zone (security partition III), and management information service zone (security partition IV).

To fulfill the network security prerequisites of the electric power industry, 5G transport networks must be constructed based on a three-layer (access, aggregation, and core) network architecture, with E2E MTN slices deployed to enforce stringent service isolation. Specifically, grid services necessitating high security, reliability, and ultra-low latency are conveyed via dedicated network slices utilizing MTN hard isolation technology, while services requiring fine-bandwidth granularity are accommodated using 10 Mbit/s FGU technology.

Government and Enterprise Private Line Scenarios

Government and enterprise private lines cater to crucial clientele, including government agencies, financial establishments, and sizable corporations, each with distinct service requisites.

As a fully integrated transport network, the 5G backhaul network can utilize FGU channels featuring TDM hard isolation capabilities to transport private lines for government and financial clients, as well as certain large enterprises. For enterprise private lines that do not necessitate hard isolation, MTN interface packet slicing can be employed. Additionally, a blend of soft and hard slicing technologies can be utilized to offer varied private line services.

FGU application in government and enterprise private lines