Symptom or Need

The client reports difficulties receiving calls in their operation, which manifest themselves through the following scenarios:

• Connection failure: Calls dialed to the DID either fail to connect or return an immediate error tone.
• Flow interruption: The end customer is unable to interact with the IVR or is not transferred to agents.
• Massive impact: A total or partial drop in incoming traffic is identified in one or more specific services.

Context / Scenarios

For an accurate diagnosis, first identify the type of service affected:

• Wolkvox telephony: The number (DID) is provided and managed directly by Wolkvox.
• Customer Telephony (Inbound Trunk): The customer owns the number and sends traffic from their own provider to the wolkvox infrastructure.

Answer / Solution

1. Minimum Information for Triage

Before climbing, it is essential to gather the following information in order to assess the extent of the fault:

• Identification : Validates the operation name and affected server.
• Affected DID: Confirm the exact number.

If it's customer telephony:

- IF the DID is not public, validate how it is dialed from Colombia.

- Verify in detail if there is an overflow from another DID and confirm the number.

• Scope of the failure:

- Determine if a single line or the entire operation fails.

- Check if the issue occurs with other DIDs in other transactions of the same client.

- Confirm if the fault occurs with a specific operator.

- Validate with the client and confirm with evidence the percentage of impact.

• Network Data (Customer Trunk Only): Documents the source IP (from where the customer sends traffic) and the destination IP (where wolkvox receives the calls).

2. Initial Validations (Level 1)

Perform the following checks in logical order:

• Dialing Test: Make direct calls to the DID to verify the result (Busy?, Network Error?, Silence?).
• Log Analysis: Query the operation server using the ANI (caller ID). Verify if the call was received and recorded in the log.
• Flow Configuration:

- Verify that the DID is correctly pointed to the corresponding IVR or Skill .

- Check time controls and recent builds in the IVR and/or skill, which may be diverting or dropping the call.

• Capacity and Security:

- Channels: Validates with Level 2 the simultaneity channels allowed for the DID.

- Check for recent updates on the server.

- Firewall: For customer telephony, rule out IP blocking in the operation's firewall, validate with the customer if there were changes to their IPs or trunk configurations, and confirm that the server IP is authorized in the Google firewall.

3. Escalation

If the problem persists after initial validations, proceed according to the scenario:

• Once the initial validations have been performed, verify with Level 2 whether the calls are being received correctly on the telephony server.
• Level 2 checks the status of the Inbound trunk or client trunk.
• For Wolkvox telephony:

or Request Level 2 verification of signaling traces to validate response codes, codecs, states, and IP addressing.
Level 2 reviews the logs on the platform, in addition to the DID trunk configurations.
Level 2 requests the TELCO leader to analyze the previous validations in order to determine if, based on these validations, it is necessary to request RTP (Real Time Transport Protocol) traces from the Cloud team.
If no traffic is detected from the provider, Level 2 escalates the formal case with the telephony provider according to the escalation matrix.

• For Customer Telephony:

or Check which IP trunk is where the traffic sent by the client enters.
or Confirm with the client from which IP address the traffic is being sent.
 

Possible Causes

• Telephone Provider: Channel saturation, massive carrier failures, or DID incorrectly routed by the provider.
• Configuration in wolkvox: Errors in the IVR logic, incorrectly configured schedules, or client IPs not registered in the Firewall (IPtables).
• Customer Infrastructure: Changes in the source PBX, unauthorized public IP, or blocks on the customer's local network.

Considerations

• Responsibilities:

1. L1 Support: Perform Triage, review logs in the Manager and run dial tests.
2. Level 2 / Telco / Cloud: In-depth network analysis, SIP/RTP trace generation and infrastructure adjustments.

• Evidence documentation: For any escalation, it is vital to attach examples with exact date and time (HH:MM:SS), the origin number (ANI) used in the tests, and the signaling traces and/or RTP (if required).

Recommendations

• Contingency Plan: If the customer requires an immediate solution and the telephone provider is failing, it is recommended to assign a temporary DID with a different provider to restore service while the underlying issue is resolved.
• Firewall Validation: Always confirm if the operation server IP is correctly registered in the Google firewall.