SIP Troubleshooting: Quick Fix Guide

A cloud-based system should be adopted for benefits like business continuity, cost reduction, increased agent productivity, and better communication with international customers. However, implementing the new technology has had challenges such as SIP security protocols and downtime issues. This article covers the top SIP trunking issues and offers solutions for troubleshooting.

Although the initial setup of your SIP trunk may not incur any costs, it will still require time and resources to configure it properly. There can be various challenges such as bandwidth problems and codec mismatches during the switch to a new provider. The following are some of the common SIP issues and advice on how to resolve them.

1. Pairing phone systems

Not every SIP is compatible with every PBX system and some licensing requirements could be causing you problems.

To solve configuration problems in SIP trunking, two methods are suggested. First, set up a packet capture between the SBCs to analyze communication and identify issues using SIP response codes. Second, test each endpoint for compatibility and make sure that firewalls and servers are not blocking any traffic.

2. Inadequate audio call quality

Poor audio call quality in SIP trunking can be due to insufficient bandwidth, network issues, or limitations in SBCs.

To troubleshoot, check the Quality of Service (QoS) setting on the router and consider upgrading if necessary. Verify the PBX codec options and use the formula “Number of Concurrent Calls x 85 kbps = Required Bandwidth” to determine the required bandwidth for high-quality calls. Common codecs used by SIP providers are G.711 and G.729, which require 24-80 kbps per call.

3. Maintaining concurrent calls

A shortage of SIP channels can cause call problems by limiting the ability of employees to make or receive calls. To determine the number of channels required, consider the number of calls you expect to handle. Organizations with high call volumes will require more SIP trunks, channels, and internet bandwidth to support their needs. Each channel is capable of hosting one phone call at a time.

To Troubleshoot, monitor your organization’s peak call volume by noting the number of concurrent inbound and outbound calls during busy periods. This number will tell you exactly how many channels you require. Higher call volume = more bandwidth and channels required.

4. Other common issues

Alternatively, it may be a smaller and easier issue to solve.
Troubleshoot the following: 

• Enough bandwidth?
  SIP trunking issues can occur when there is insufficient bandwidth which causes slow applications, internet and degraded call quality. Upgrading bandwidth with the internet provider is a solution to this problem.

• Codec mismatch?
  Codec mismatch can cause difficulty in hearing callers. A Codec mismatch occurs when one side of the two-way audio of the VoIP call is not exchanging real-time transport protocol (RTP) within the same codec. This can be resolved by contacting the SIP provider to match the codecs.

• Waiting for your numbers to transfer over?
  With SIP trunking you are able to retain existing communications infrastructure and phone numbers, but it may take a few weeks for everything to transfer over. In case of delay, be sure to work with your provider to speed up the process or find a temporary solution. 

The implementation of new telecommunication software has a learning curve and initial difficulties can be resolved with SIP troubleshooting. Make sure to contact your provider for support and unlimited channels to aid migration of PBX to the cloud and secure SIP connections and global connectivity.