How do you know the Vivo SIP trunk went down?
By calling a number that comes in over it. If the call does not connect, the SIP response tells you where it stopped: a 503 with Q.850 cause 34 points to no channel available, a 403 points to an unauthorized trunk, and no response points to a network that is down. Registration on the PBX is not enough: a registered trunk can still reject calls.
On a SIP trunk, the inbound call is the one that fails silently most often: if the carrier stops delivering your number, the PBX sees nothing, and the first person to notice is usually a customer.
Which SIP codes and Q.850 causes appear in a failure?
The codes below are the same with any carrier; they come from SIP and Q.850, not from a specific network. The Q.850 cause appears in the Reason header of the SIP response, when the network sends it, and on an E1 it comes in the disconnect message. The table shows what each signature usually points to.
| Symptom | SIP code / Q.850 cause | What it usually points to |
|---|---|---|
| Rejected at peak times | 503 with cause 34 | Channels exhausted, yours or the route’s |
| Rejected at any time | 503 with cause 38 or 41 | Network or temporary failure at the carrier |
| Outbound rejected | 403 Forbidden | IP, credentials or caller number not accepted on the trunk |
| Number not found | 404 Not Found or cause 1 | Number not activated, not routed or being ported |
| No response | 408 Request Timeout or cause 102 | A device on the route is down, or a firewall is blocking |
| Rejected right after the INVITE | 488 Not Acceptable Here | No matching codec between your side and the trunk |
| Destination out of service | 502 Bad Gateway or cause 27 | The destination’s equipment does not respond |
A call that connects with no audio on one side has no SIP code: the problem is in the media, almost always NAT or a firewall. The guide silent calls and one-way audio shows how to investigate.
What changes on a Vivo E1 trunk?
On an E1 trunk, the failure can start at the physical layer. Loss of signal, loss of frame and remote alarms show up on the E1 card or gateway before any call. An E1 has 30 voice channels, and some of them can be blocked without taking the whole trunk down, which only shows up as rejections at peak times.
Q.850 causes arrive in the disconnect message, and the most common in a failure are 34, 38 and 41. Write down the alarms seen and the time: they are the first thing the carrier asks for.
How do you separate a Vivo failure from a failure on your side?
With the call seen from the outside and the capture seen from the inside. If the test call does not appear on your PBX or SBC, the failure is upstream of them. If it appears and one of your devices rejects it, the failure is yours. The Via, Server and User-Agent headers of the response show who generated it.
During number porting, a number can be left without a route for a while. Under the RGST, Anatel Resolution No. 777/2025 (Resolução Anatel nº 777/2025), art. 103, the transition period must stay within 2 hours in 99% of cases and never exceed 24 hours.
What evidence should go in the Vivo ticket?
A ticket with data the carrier can search for in its own records. The exact time with time zone, the calling and called numbers, the Call-ID and the full SIP response make it possible to locate the call on the network. Confirm the ticket channel and response time in your contract.
- Date and time of each attempt, with time zone, and the last healthy call.
- Calling number (A) and called number (B), and the circuit identifier listed in the contract.
- The SIP response line, the
Reasonheader and the Call-ID. - How many attempts failed, over what interval, and whether every destination fails or only some.
- On an E1, the alarms seen and the affected channels.
- The packet capture, if you have one, and the reference number of each contact with the carrier.
How does Monitor help with a Vivo trunk?
Monitor calls the numbers on your trunk at the agreed pace, retries each failure before alerting and opens the incident with the SIP code and Q.850 cause of each call, in a block ready to paste into the ticket. It does not integrate with the carrier: it calls the numbers, so it works with any carrier.
See how in SIP trunk monitoring.
Frequently asked questions
Does Monitor integrate with Vivo?
No. Monitor does not integrate with any carrier or any PBX. 2N5 calls the numbers you choose, from its own platform, the way a customer does. That is why the same monitoring works for SIP and E1 trunks from Vivo and from any other carrier.
What is the repair time for a Vivo trunk?
It depends on what is in your contract. Repair time, availability target, ticket channel and compensation vary from contract to contract, so confirm yours. What Monitor delivers is the record of when the trunk failed and came back, to compare against what was contracted.
How do I know whether the problem is Vivo or my PBX?
From where the response came from. A test call placed from the outside shows what the network returned. If it never reaches your PBX, the failure is upstream of it. If it arrives and the PBX rejects it, the failure is yours. A SIP capture shows, through the headers, which device generated each response.
Does a test call count against my channel limit?
Yes, for a few seconds, when the tested number comes in over your trunk. Each test is a short call to a number you choose, such as an IVR, a test tone or an echo service, within a call limit, and it never touches your customers' calls.