How do you identify that the Embratel trunk went down?
From the response to a real call placed from the outside. When a number that comes in over the trunk does not connect, the SIP response and, when sent, the Q.850 cause tell you whether there was no channel, whether the number dropped out of the route or whether the network did not respond. Without that call, the outage only shows up when volume falls or someone complains.
In a contact center, a drop in volume could be a failure or just a calm day. The test call tells the two apart, at any hour.
Which failure signatures appear on a SIP trunk?
The signatures below come from SIP and Q.850 and apply to any carrier; they do not describe any particular carrier’s network. The Q.850 cause appears in the Reason header of the response, when the network sends it. For each code, the reference page explains the diagnosis in detail.
| Symptom | SIP code / Q.850 cause | What it usually points to |
|---|---|---|
| 0800 or landline number does not connect | 404 Not Found or cause 1 | Number without a route, not activated or being ported |
| No route to the destination | cause 3 | The network has no path to the called number |
| Rejected at peaks | 503 with cause 34 | Channels exhausted on the trunk or the route |
| Rejected at any time | 503 with cause 38 | Network out of service |
| Destination does not respond | 480 Temporarily Unavailable or cause 18 | The destination did not answer or respond in time |
| Outbound rejected | 403 Forbidden | IP, credentials or caller number not accepted |
| Internal error on the route | 500 Server Internal Error or cause 127 | Interworking failure between networks, with no more specific cause |
What about an Embratel E1 trunk?
On an E1 trunk, the first signs come from the physical layer: loss-of-signal, loss-of-frame or remote alarms on the card or gateway. With a healthy physical layer, failures show up as Q.850 causes in the disconnect message, with the same meaning they have on a SIP trunk.
Because an E1 has 30 voice channels, a partial block does not take the trunk down: it reduces capacity, and rejections with cause 34 appear only at the busiest times.
How do you prove the failure in the ticket?
With the record of each failed call, in data the carrier can search for: exact time with time zone, origin and destination, Call-ID, the SIP response and the Q.850 cause. Several consecutive failures, at recorded times, support the ticket better than a verbal report. Confirm the ticket channel and deadline in your contract.
- Date and time of each attempt, with time zone, and of the last healthy call.
- Calling number (A), called number (B) and the circuit identifier in the contract.
- The SIP response line, the
Reasonheader and the Call-ID of each attempt. - How many attempts failed and over what interval.
- On an E1, the alarms seen and the affected channels.
- The reference number of each contact, to follow up on the response.
How does Monitor help with an Embratel trunk?
Monitor calls the numbers on your trunk, including the 0800, at the agreed pace, retries each failure before alerting and opens the incident with the SIP code and Q.850 cause of each call. It does not integrate with the carrier or the PBX: it calls the numbers, so it works with any of them.
See how in SIP trunk monitoring and in 0800 and IVR monitoring.
Frequently asked questions
Does Monitor work with Embratel trunks?
Yes. 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 it works with SIP and E1 trunks from Embratel and from any other carrier, with nothing installed on your side.
Can I monitor the 0800 that runs on the Embratel trunk?
Yes. Each number is a voice circuit in Monitor, with its own schedule and the people who should know when it fails. The test call dials the 0800 like a customer and checks that the IVR answered with the right message, including overnight and on weekends.
How do I know how long the trunk was down in a month?
By measuring all the time. Because Monitor calls each circuit at the agreed pace, it records when each failure started and ended. The SLA report shows availability for the month and the last 12 months. Confirm in your contract which measurement method applies for compensation.
Does the Q.850 cause always appear in the response?
No. The Q.850 cause only appears when the network sends it, in the Reason header of the SIP response, or in the disconnect message on an E1. When it is there, it helps tell apart no channel available, a nonexistent number and a network failure. When it is not, the SIP code and the time already locate the call.