Overview of iFIT

Definition

In-situ Flow Information Telemetry (iFIT) is an in-band OAM technology that uses service packets to measure performance indicators of an IP network such as the packet loss rate and delay.

Purpose

In the 5G era, the Enhanced Mobile Broadband (eMBB), ultra-reliable low-latency communication (URLLC), and Massive Machine-Type Communications (mMTC) scenarios pose higher requirements on transport networks. To meet these requirements in terms of network O&M and performance monitoring, transport networks need the following:

• Effective troubleshooting methods are needed to improve O&M efficiency, because deterioration of network performance is difficult to diagnose.
• A new performance measurement mechanism based on service flows is needed to accurately reflect actual user traffic in real time. Traditional performance measurement methods support only coarse OAM granularities (such as ports, tunnels, and pseudo wires).
• Functions such as network-wide delay visualization, delay abnormality monitoring, and delay-based routing are needed to improve 5G user experience for delay-sensitive 5G services.

Currently, OAM performance measurement can be classified into out-of-band measurement and in-band measurement by measurement type. Out-of-band measurement includes NQA and TWAMP, and in-band measurement includes IP FPM. These methods have the following advantages and disadvantages:

• NQA can monitor the performance of multiple protocols running on a network. However, it measures the performance using simulated packets (constructed based on the types of measurement instances) rather than actual service packets transmitted on networks. As such, the performance indicators collected by NQA may not represent the actual service quality and should be used as reference only.
• TWAMP can insert probe packets into service flows, achieving fast and flexible deployment. However, to perform measurement, it has packets sent at intervals. This produces low-precision measurement result and does not support hop-by-hop measurement.
• IP FPM is an in-band measurement method, but it has high requirements on network devices, applies to limited scenarios, and is complex to deploy.

The OAM detection technologies currently available cannot meet requirements on transport networks. Huawei therefore launches the iFIT performance measurement solution. In terms of performance monitoring, iFIT meets the requirements of 5G transport networks and has the following characteristics:

• Expandability: iFIT has high detection precision, is easy to deploy, and can be expanded to meet future requirements.
• Fast fault diagnosis: iFIT provides in-band detection to measure the delay and packet loss of service flows in real time.
• Visualization: iFIT allows performance data to be presented on a Graphical User Interface (GUI) for quick location of failure points.

Benefits

iFIT offers the following benefits:

• Allows customers to monitor the network running status through an NMS and determine whether the network quality complies with SLAs.

• Enables customers to promptly adjust services according to obtained measurement results, thereby ensuring proper transmission of voice and data services and enhancing user experience.