***

title: SIP Call Ladder
slug: sip-call-ladder
description: View SIP ladder diagrams and download PCAP files for call analysis
---------------------

For a complete page index, fetch https://docs.synthflow.ai/llms.txt. For full documentation content, fetch https://docs.synthflow.ai/llms-full.txt.

Synthflow AI provides a **SIP Call Ladder** feature, which allows detailed technical analysis of your calls by displaying the SIP signaling flow and allowing you to download packet capture files for deeper investigation.

This tool is useful for:

* **Troubleshooting call failures** by examining the SIP signaling at a glance.
* **Understanding call flow** between different network elements for full transparency on the Synthflow AI network.
* **Debugging connectivity issues** with detailed packet analysis and the ability to download a pcap.
* **Self-service problem resolution** without needing to contact support.

***

## Accessing SIP Call Ladder

<Steps>
  <Step>
    Navigate to the **Logs** section in your workspace. For more information about Logs you can [learn more here](/logs)
  </Step>

  <Step>
    Select any call from your call logs to view its details.
  </Step>

  <Step>
    Click on the **SIP Ladder** tab to view the SIP signaling diagram.

    ![](https://files.buildwithfern.com/synthflow.docs.buildwithfern.com/94040208f850a6322661e4e7fba269f3995ec2bd178c55c52d0801cb5c6667a5/docs/assets/screenshots/sip-ladder-select-tab.png)
  </Step>
</Steps>

***

## Understanding the SIP Ladder Diagram

The SIP ladder diagram shows the complete signaling flow between different network elements involved in your call:

* **Vertical lines** represent different network elements (your agent, our network hops, SIP carrier)
* **Horizontal arrows** show SIP messages flowing between elements
* **Message types** include INVITE, 100 Trying, 180 Ringing, 200 OK, BYE, etc.
* **Timestamps** help you understand the timing of each signaling event

This visual representation should make it easier to view and debug SIP signaling at a glance, for anything else we provide an option to download the SIP pcap file itself.

***

## Downloading PCAP Files

For advanced troubleshooting, you can download the complete packet capture (PCAP) file for any call. Please be aware you will need a program to view .pcap files, we recommend Wireshark for this.

<Steps>
  <Step>
    From the **SIP Ladder** tab, locate the **Download PCAP** button.
  </Step>

  <Step>
    Click to download the PCAP file to your local machine.

    ![](https://files.buildwithfern.com/synthflow.docs.buildwithfern.com/e0cc89fa60d699778b711bb0487d98bd007254da2313ca79b00c00d2f4dce1df/docs/assets/screenshots/sip-ladder-pcap-download.png)
  </Step>

  <Step>
    Use tools like **Wireshark** to analyze the packet capture file for detailed network analysis.
  </Step>
</Steps>

***

## Troubleshooting Common Issues

When analyzing SIP ladder diagrams, look for these common patterns:

| Issue                       | SIP Ladder Pattern             | What to Check                                                                       |
| --------------------------- | ------------------------------ | ----------------------------------------------------------------------------------- |
| **Call Not Connecting**     | INVITE sent but no response    | Check the agents number, specifically SIP Domain if you add your own numbers.       |
| **Call Drops**              | Unexpected BYE message         | Check for network timeouts or carrier issues                                        |
| **Authentication Failures** | 401 response                   | Verify SIP credentials and account permissions                                      |
| **Authentication Failures** | 403 responses                  | Verify SIP credentials and calling permissions                                      |
| **One-Way Audio**           | 200 OK received but RTP issues | Verify media codec compatibility, source and destination IP's and firewall settings |

***

## Getting Additional Help

If you're unable to resolve issues using the SIP ladder and PCAP analysis:

1. **Check the [Telephony Errors](/telephony-errors) page** for specific error code explanations.
2. **Review your number configuration** and the call settings for correct formatting.
3. **Contact support** with the PCAP file and SIP ladder screenshot for advanced troubleshooting along with the URL of the agent so we can help.