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Wholesale VoIP Feature Article

Mitigating Common Issues with VoIP Calling

May 04, 2017

By Laura Stotler, TMCnet Contributing Editor

One of the biggest problems in the VoIP world is complaints from end users about call quality, calls getting dropped and other technical issues. Technology for handling packet-based voice calls has improved greatly over the last couple of decades, but end users are quick to complain and who can blame them?

There are six main issues behind the most common complaints and all of them are relatively easy to troubleshoot and prevent altogether. Tim Klein, a technical service representative II at wholesale VoIP provider VoIP Innovations (News - Alert), singled out the most common problems as well as providing suggestions so that managed service providers (MSPs) can mitigate and avoid them.

Of course, audio issues are perhaps the most popular problem generating complaints from end users.  MSPs routinely report their customers experience either no audio, one-way audio, or other disruptions like static and jitter. According to Klein, the first step for MSPs should be downloading the free Wireshark Packet Capture analyzer to get a picture of the SIP and RTP streams traveling to and from the MSP on their network. The analyzer will show packets being sent across the public internet and entering the MSP’s network as well as traveling through equipment like firewalls, routers and SBCs so trouble areas may be pinpointed. Other potential sources of bad audio could be with a wholesale Underlying Carrier (ULC) or with the public internet, in which case the MSP would need to contact their ISP to troubleshoot.

Another common complaint among end users of VoIP is that calls are not completing. For outbound calls, Klein suggests MSPs send in call examples so he can check if the calls show up in CDRs or if the calls are even reaching the wholesale network. If inbound calls are causing issues, he would also check the CDRs to see if the calls are successfully reaching the network from the carriers. Live testing can also help identify the issues. Abnormal disconnects are another common problem, with calls disconnecting without the originating nor terminating parties ending the call. CDRs are also helpful here, enabling techs to see if the disconnect came from the ULC or through an RCC 16, which is the SS7 standard for call clearing. That way the issue can be escalated either to the wholesale provider or the carrier to determine what is causing the disconnect.

Translations can be another tricky issue for MSPs, and occur when a number is ported from one carrier to another. If the first carrier fails to remove all routing from their equipment for the number, calls will be erroneously routed to the wrong destination. In this case, the new carrier will need to work with the old carrier to ensure all translations have been removed from their equipment to ensure calls are routed smoothly. Outbound CNAM (caller ID) can also be problem for end users, and therefore a headache for MSPs. If CNAM storage is updated that may be the culprit, as it typically takes new entries 72 business hours to propagate to the National Database. If that window has been exceeded, the next step is to ensure the CNAM provider has the correct, updated entry on file. Finally, if the National Database information is correct, the CNAM Dip vendor needs to be checked for the update. If all vendors have the correct, updated information, the MSP would then need to contact the receiving phone company to ensure their records are correct and up to date.

A final complaint among end users is with T38 faxing functionality, a service many MSPs offer to their customers. This type of service enables emails to be converted to fax, and then back to email on the receiving end. Things typically go awry if an end user’s sender policy framework (SPF) record is not set up correctly, based on an illegitimate email or some other misconfiguration. End users may also complain that they are not receiving inbound faxes, and the Wireshark analyzer is handy for troubleshooting here as well.

No matter how solid an MSPs service is, things can go wrong with VoIP calling given the number of outside players and variables involved to process a call. With proper troubleshooting, MSPS can quickly and effectively identify issues and alleviate the most common end users complaints.

Edited by Maurice Nagle

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