Dear Rashed Hasan Ratul,

The following links will give you a good start:

https://www.ciscopress.com/articles/article.asp?p=606583

https://www.cisco.com/c/en/us/support/docs/voice/voice-quality/5125-delay-details.html

https://www.gsma.com/futurenetworks/wp-content/uploads/2020/02/4G5G-Network-Experience-Evaluation-Guideline-_GSMA.pdf

https://www.gl.com/telecom-test-solutions/testing-satellite-communications.html

Call Setup Delay is an important performance metric in telecommunication networks, as it directly impacts the user experience. The appropriate way to measure Call Setup Delay depends on the type of network and the specific call setup protocol being used. However, the following general steps can be followed:

1. Identify the call setup protocol: The first step is to identify the call setup protocol being used in the network. This could be SIP (Session Initiation Protocol), H.323, ISDN (Integrated Services Digital Network), or others.

2. Define the measurement points: Once the call setup protocol is identified, the next step is to define the measurement points where the Call Setup Delay will be measured. This could be at the user equipment, at the network edge, or at the core network.

3. Start the measurement: To measure Call Setup Delay, a test call is initiated between two endpoints. The time at which the call is initiated and the time at which the call is established are recorded.

4. Calculate the delay: The Call Setup Delay is calculated as the time difference between the initiation time and the establishment time. This can be done using simple arithmetic.

5. Repeat the measurement: To ensure accuracy, the measurement should be repeated multiple times to get an average value of the Call Setup Delay.

6. Analyze the results: The final step is to analyze the results and compare them against the performance objectives or service level agreements (SLAs) for the network. If the Call Setup Delay is found to be higher than the acceptable threshold, further testing and troubleshooting may be required.

It is important to note that the appropriate way to measure Call Setup Delay may vary depending on the network and the call setup protocol being used. Therefore, it is important to reference the relevant standards and best practices for the specific network being tested.

The appropriate way to measure Call Setup Delay in telecommunication networks depends on the specific network. In some networks, Round-Trip Time (RTT) is a good measure of Call Setup Delay, while in other networks, Signaling Delay is a better measure.

• Round-Trip Time (RTT) is the time it takes for a signal to travel from one point to another and back again. In the case of Call Setup Delay, RTT is measured from the time the caller presses the "send" button on their phone to the time the callee's phone rings. This is a good measure of Call Setup Delay in networks where the signaling delay is relatively small, such as in wireline networks.
• Signaling Delay is the time it takes for the network to exchange signaling messages between the caller and callee's phones. Signaling messages are used to establish the call and to negotiate the call parameters, such as the codec and the bandwidth. This is a better measure of Call Setup Delay in networks where the signaling delay is relatively large, such as in wireless networks.

In general, the best way to measure Call Setup Delay is to use both RTT and Signaling Delay. This will give you a more complete picture of the overall delay in establishing a call.

Here are some of the factors that affect the choice of measurement method:

• The type of network: Wireline networks typically have lower signaling delays than wireless networks.
• The signaling protocol: Different signaling protocols have different overhead, which can affect the signaling delay.
• The network load: The network load can also affect the signaling delay.

The appropriate way to measure Call Setup Delay should be decided by considering the specific network and the factors that affect the delay.