Configurations with Common Interruptions
Overview
Sharpen is a cloud-based platform designed to connect through a standard web browser with minimal configuration requirements. However, certain network configurations, particularly those carried over from legacy on-premise VoIP solutions, can interfere with Sharpen's performance. This article outlines configurations that are known to cause service disruption, configurations that are not recommended, and common network issues that may affect call quality.
For additional information, please visit: Platform Requirements
Unsupported Configurations
The following configuration is known to cause direct disruption to Sharpen and is not supported. If this configuration is confirmed to be in use when a service issue is reported, Sharpen will validate the health of its own endpoints and provide guidance but cannot be held responsible for the resulting experience. The customer assumes responsibility for troubleshooting and resolving issues arising from unsupported configurations.
SIP ALG Despite its name, SIP ALG (Application Layer Gateway) is not compatible with most enterprise VoIP solutions, including Sharpen. This setting may appear on network devices as "SIP ALG," "SIP," "VoIP," or a similar label depending on the manufacturer. Common symptoms of SIP ALG being enabled include intermittent disconnections, dropped calls, one-way audio, and registration failures.
ISPs frequently enable this setting to support their own VoIP products, which means it may be active on your network without your knowledge. Disabling it may require escalating through multiple tiers of ISP support. Confirming this setting is off should be one of the first steps in any voice quality troubleshooting process.
Not Recommended
The following configurations may operate acceptably in well-optimized environments, but Sharpen's ability to support quality issues is limited when these configurations are in use and our endpoints are confirmed healthy. Sharpen will provide best-effort guidance but does not offer specific support for these setups beyond what is outlined in the Network Requirements documentation.
Virtual Desktop Infrastructure (VDI) VDI environments introduce additional infrastructure and virtualization layers that can create points of failure for real-time voice traffic, which Sharpen has limited ability to diagnose or support. There is nothing inherently incompatible between VDI and voice, but the environment must be carefully architected to prioritize Sharpen's traffic. If VDI is in use, consult your VDI provider's documentation for VoIP optimization guidance. Resources from common VDI providers include:
VPN VPNs add a virtual network layer that can introduce latency and packet loss, both of which directly degrade voice quality. If a VPN is required, configure split tunneling so that Sharpen traffic bypasses the VPN and routes directly over the internet. Sharpen will not provide support for voice quality issues caused by VPN usage.
MPLS configurations are commonly inherited from previous on-premise or direct-to-data-center VoIP deployments. Unlike those solutions, Sharpen is a cloud-based platform that expects the lowest-latency path over the public internet to the nearest availability zone. Routing traffic through an MPLS undermines this architecture. The recommended approach is a direct internet connection using standalone network equipment, which provides the most direct and lowest-latency path to Sharpen's infrastructure.
Stateful Packet Inspection (SPI) Similar to SIP ALG, SPI is a firewall feature that inspects packet states to determine whether traffic should be permitted. Because WebRTC traffic is stateless, SPI may misidentify it as unapproved UDP traffic, resulting in the inability to establish a connection or causing one-way audio. If voice quality issues are present and SPI is enabled, disabling it or creating an exemption for Sharpen traffic is recommended.
ISP Combination Devices Residential "combination" devices, those that integrate a modem, router, and Wi-Fi into a single unit, are commonly managed by ISPs and may have settings such as SIP ALG enabled by default without being visible to the end user. Since these are ISP-managed devices, resolving configuration issues typically requires contacting ISP support directly.
Sharpen recommends using a standalone modem paired with a separately managed router whenever possible, as this gives you full control over all relevant network settings. If a standalone setup is not an option, ask your ISP whether the combination device can be placed in bridge mode, and then connect a third-party router to manage local networking.
Common Network Issues
NAT Misconfigurations Network Address Translation (NAT) maps private internal IP addresses and ports to public-facing addresses. While the STUN protocol is designed to help WebRTC and VoIP navigate NAT environments, certain NAT configurations can still cause issues.
A common example is using a SonicWall firewall without enabling its Consistent NAT feature. Without consistent NAT, the same internal IP and port pair may be mapped to different public addresses across sessions, resulting in one-way audio. Consistent NAT uses an MD5 hashing method to ensure a stable, consistent mapping between internal and external address pairs, enabling proper two-way audio.
UDP Timeout Below 240 Seconds: Sharpen's SIP registration interval is 4 minutes (240 seconds). If your network is configured to time out UDP connections in under 240 seconds, active registrations will be dropped unexpectedly. Symptoms include dropped calls, the inability to receive inbound calls on the affected extension, and a sawtooth pattern in latency monitoring graphs. Outbound calls will typically still connect, as registration is re-established at the time of dial. Adjusting the UDP timeout to 240 seconds or greater will resolve this issue.
This article is part of a series on Admin Configuration topics.