Content Comparison

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• SIP ALG is enabled

  • Perhaps contrary to its name, SIP ALG is not compatible with most enterprise VoIP solutions, such as Sharpen. Depending on the manufacturer, network device configurations will show up as “SIP ALG”, “SIP”, “VoIP”, or something similar. Intermittent disconnection, dropped calls, one-way audio, and the inability to register are common symptoms when SIP ALG is enabled.

  • Depending on your device manufacturer or ISP, it may be difficult to get a straight answer on confirming this setting is off. Commonly, ISPs will have this setting enabled, because it supports their own options for VoIP solutions. It is not uncommon to have to work through a couple layers of support or technical team members to validate the proper setting is turned off. 

• UDP timeout is set less than 240 seconds

  • Sharpen’s expected SIP registration interval is 4 minutes (240 seconds). If your network is set to “timeout” UDP connections at less than that, it will disconnect an active registration. Depending on when this happens, you’ll see the following symptoms.

    • Dropped calls

    • Inability to be reached on the phone which has lost its connection. 

    • You’ll be able to dial outbound without issue, since registration is established on an attempted outbound call, if it does not already exist. 

    • You’re probably seeing a sawtooth pattern in your latency graphs.

• ISP provided “combination” network equipment

  • Especially if you’re working from home on your residential internet connection, be weary of the Internet Service Provider (ISP) controlled settings which may exist on these managed devices. “Combination” devices are typically those which integrate modem, router, and wifi into one device. While in principle, the integration of these functions problematic, they can sometimes come with configuration hurdles which are difficult to overcome since you, as the borrower of the device, do not have administration access to the devices. It is not uncommon for settings like SIP ALG to be enabled but invisible to you as the user. These situations require that you work with your ISP’s support team to change a setting. 

  • As a result, Sharpen discourages the use of combination network equipment. Instead we recommend purchasing a stand alone modem which is compatible with your ISP, and connecting a router of choice to it. This allows you full control of any potentially conflicting setting. Most self-managed devices have these problematic settings disabled by default.

  • If you can not acquire a stand-alone modem and router, we recommend reaching out to your ISP to see if they can place your combination device in “bridge” mode, then purchasing and connecting a 3rd party router to handle the local networking. 

• VPN

  • VPNs have many valid use cases, especially for work from home users. However, VPNs are not always configured to be optimal for voice traffic. Adding the additional virtual layer to the network, in most situations, will cause a recognizable degradation in network performance. Voice requires low latency, with minimal packet loss. As a result, if the VPN introduces too much interruption, your quality of service will be impacted. If VPN is necessary, it is recommended to configure it so Sharpen traffic can be omitted through the us of split tunneling.

Ports Protocols and

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Domains

While most work-from-home users will be all set, it is important to make sure the following ports/protocols are free to communicate with our environment. If, for some reason, your ISP has restricted activity on these ports, you'll need to work with them to allow two-way traffic.

Access to these domains need to be open regardless of the isolation zone (IZ0,IZ1) in which your account is built. These include some supporting services and libraries which allow Sharpen to run as designed.

• 80 HTTP - Default port for web browser traffic

• 443 HTTPS - Default secure port for web browser traffic

• 8089 TCP - Used for establishing Websocket connections.

• 8090 TCP - Used for establishing Websocket connections.

• 9002 TCP - Used for establishing WebRTC connections.

• 10000-20000 UDP - Port range used for media transmission through WebRTC.

If whitelisting traffic, please allow the following.

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*.sharpencx.com - main app domain

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*.sharpen.cx - supplemental main app domain

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*.cx.shpn.co - dotCX domain

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*.sipvbx.com - voice infrastructure domain

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*.fathomvoice.com - legacy api domain

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*.s3.amazonaws.com - long-term storage domain for audio and image files

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*.yealink.com - Yealink registration domain

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*.ckeditor.com - visual editor/UI library domain

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*.loggly.com - logging tool domain

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*.pendo.io - logging tool domain

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*.ingest.io - logging tool domain

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*.gstatic.com - font library domain

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*.googleapis.com - font library domain

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Isolation Zone Domains

Access to these domains should be open with respect to which isolation zone your account is built in.

• Isolation Zone 0 | You login to app.sharpencx.com.

• Isolation Zone 1 | You login to app.iz1.sharpen.cx

Network performance

Uninterrupted, consistent network performance is required for a good experience with the Sharpen platform. Due to the inherent nature of Voice interactions to be real-time, we need consistency in the underlying network. Otherwise, users may experience dropped calls, choppy call quality, latency, or an overall slow experience.

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