At MWC Shanghai 2019, the world's first In-situ Flow Information Telemetry (iFIT) pilot on the 5G transport network has been successfully completed by Beijing Unicom (China Unicom's Beijing Branch) and Huawei.

The iFIT solution implements enhanced service recovery speeds to help Beijing Unicom build an intelligent, visualized 5G transport network, through capabilities such as millisecond-level in-band flow measurement, real-time monitoring of network service quality to meet Service Level Agreement (SLA) requirements, and second-level silent fault locating.

In the 5G era, diverse new services have far higher network quality requirements: for example, virtual reality/augmented reality (VR/AR) services require more bandwidth (80 Mbit/s to 260 Mbit/s) and a lower packet loss rate (10^-5 to 10^-6 ).

In a similar vein, carriers also need to switch sales focus from network bandwidth to user service experience. However, ensuring the quality of the user service experience is a major challenge for transport networks.

In network operations and maintenance (O&M), a conventional approach uses test packets to obtain data. However, this approach fails to accurately reflect service quality information, because the paths of test packets and service packets can be inconsistent, especially for difficult-to-detect silent faults, such as minor packet loss. Indeed, the precision of conventional service packet loss detection can only reach 10^-3 , which may well result in undetected packet loss in VR/AR services.

In addition, the shortest interval at which information can be collected is minutes. As a result, faults can only be diagnosed post-event, or after quality deterioration has occurred, with the fault diagnosis period often extending to hours, days, or even weeks.

Huawei's innovative iFIT solution takes a hardware approach, using per-packet detection to identify minor exceptions in real-time service network traffic. Rather than using test packets, iFIT directly measures information carried in packets to obtain information, including the delay and packet loss rate of each service. Indeed, the precision of service packet loss detection can reach 10^-6 , a 1000-fold increase compared to the conventional approach.

The iFIT solution can be used together with telemetry's millisecond-level data collection, to implement real-time service quality visualization, and minute-level fault demarcation and locating. This effectively meets SLA requirements for new 5G services, including VR/AR.

In October 2018, Huawei submitted the draft of iFIT — "In-situ Flow Information Telemetry Framework" — to the Internet Engineering Task Force (IETF). Huawei's iFIT is the industry's first in-band flow measurement solution to have been deployed commercially. In June 2019, Huawei's iFIT solution won the Best of Show Award Special Prize at Interop Tokyo 2019 — one of the most prestigious events in the industry.

In its pilot, Beijing Unicom used the Huawei iFIT solution, with Huawei routers and Network Cloud Engine (NCE) deployed on the forwarding and control planes respectively, to simulate various network faults. Even when hard-to-detect faults occurred — such as single packet loss or delay beyond the threshold — iFIT demonstrated its strengths in accurately measuring and displaying the fault information on NCE, which then analyzed the information, and quickly optimized paths.

"iFIT does not require external probes. The service boards of routers can obtain the key performance indicators (KPIs) of real service flows, hop by hop, and the delay precision is high. This is a great breakthrough in the O&M technology of transport networks," commented Mr. Zang, Manager of Beijing Unicom Transport Center. "With the issuance of 5G commercial licenses, the 5G process will be accelerated, and the iFIT solution will play an important role in SLA assurance."

"With the advent of 5G, diversified service types, and differentiated SLAs will bring huge challenges to transport networks," said Huang Xinyu, Director of Huawei 5G Transport Solution. "5G-oriented high-precision detection technology has always been the direction of our research. The iFIT pilot marks a new level of innovation and cooperation between Beijing Unicom and Huawei in the 5G transport field."

Beijing Unicom and Huawei have invested heavily in 5G application innovation and the industry ecosystem, to break through industry bottlenecks. In the future, Beijing Unicom and Huawei will continue to carry out joint innovation on the transport side, verify new 5G transport technologies and features, and explore 5G transport network construction modes and specifications, laying a foundation for the upcoming large-scale, commercial use of 5G in China.