Comcast Business VoiceEdge®
Over The Top Network Requirements

A customer’s guide to Comcast Business VoiceEdge service

Network compatibility
Troubleshooting
Bandwidth requirements
VoIP network requirements
Router & Firewall settings
WiFi Recommendations

This guide contains requirements and recommendations for customers using the Comcast Business VoiceEdge® service over their Internet connection, a delivery model known as Over The Top, or OTT for short. This guidance is designed to help you optimize call quality for your OTT VoiceEdge configuration. All steps and requirements must be completed and met prior to day of install.

We recommend that you review this guide with your company’s Information Technology (IT) specialist to ensure they can accommodate the various technical specifications discussed below.

If you have questions about any of the requirements or recommendations contained in the Guide, please speak to your Comcast Business sales representative, sales engineer, or project manager.

Service Summary

Over the Top

Your Comcast Business VoiceEdge service operates over a broadband Internet connection you purchase separately from Comcast Business or another Internet Service Provider (ISP).

This OTT option is available nationally and supports one or more phone lines per location. It is ideal for customers that want to maintain their current Internet connectivity, self-manage their service, and/or have locations where Comcast Business internet service is not available.

Network Compatibility

Is Business VoiceEdge compatible with my network?

Comcast Business VoiceEdge requires certain network settings and configurations to work properly as an OTT service.

You should work with your IT person or ISP to troubleshoot and resolve any network issues prior to VoiceEdge installation. If you are using Comcast Business Internet and are experiencing issues, please contact Customer Care at (800) 391-3000 to help resolve the issue.

The Basics: Wiring, Bandwidth, and Troubleshooting

Network Requirements

Comcast Business VoiceEdge IP phones must be physically connected to a network with a Cat 5 or 6 ethernet cable. Phones cannot connect via a wireless (WiFi) network for initial setup.

Comcast Business recommends using a Network Switch that can provide Power Over Ethernet (PoE) to eliminate the need for a separate power adapter for each IP phone.

Bandwidth Requirements: 100 kbps per call

Comcast Business VoiceEdge OTT shares the same data connection with all the computers and devices connected to your Internet network. Any spike in data usage could affect call quality if there is insufficient bandwidth.

Comcast Business VoiceEdge OTT requires a minimum of 100 kbps available bandwidth per voice call in both upstream and downstream directions, including on local area networks (LAN) and wide area networks (WAN).

For example, if you have five (5) phones that each receive a phone call at the same time, you need 500 kbps of bandwidth available. If you have ten (10) phones, you will need 1 Mbps.

Ability to Troubleshoot

Keep in mind, with an OTT service, Comcast Business will have limited insights into the voice network and you might need to identify and fix issues relating to your Internet service or any other component between the Internet and the phones.

Advanced: Network Settings, Configurations, and Port assignments

This section reviews technical details. You may need to consult with your organization’s IT specialist.

Voice over IP (VoIP) Network requirements

Three general network requirements must be met for acceptable call quality.

If any of these are outside of our recommend thresholds, you could experience dropped calls or poor call quality.

  1. Packet-loss less than 2%
  2. Jitter of less than 20ms
  3. Propagation delays of less than 40ms (measured 1-way from the phone to the Comcast Business voice infrastructure)

Router and Firewall Settings

Your router, firewall, and other edge devices on your network must be configured appropriately to support voice service.

SIP ALG and NAT settings

Disable the following:

  • SIP ALG
  • SIP Passthrough
  • Deep Packet Inspection (DPI)
  • Stateful Packet Inspection (SPI)

Confirm your Session Initiation Protocol (SIP) Application Layer Gateway (ALG) default setting is turned to off. Having the SIP ALG enabled may modify the SIP signaling to the phone and negatively impact Comcast Business VoiceEdge performance.

If your router has a setting for Network Address Translation (NAT) endpoint filtering, make sure it is set to: ‘Endpoint Independent Transmission Control Protocol (TCP) and User Datagram Protocol (UDP)’.

DPI and SPI should be disabled as they may interrupt or alter the signaling and media being passed over the network.

Quality of Service and DSCP support

Comcast Business VoiceEdge devices support Differentiated Services Code Points (DSCP) marking, which allows you to prioritize voice traffic on your LAN. With DSCP marking, if there is a spike in data usage, your phone calls will take priority.

To enable DSCP marking for Voice traffic, please configure your router and firewall settings accordingly:

  • Media – Expedited Forwarding 46 (DSCP-46)
  • Signaling – Assured Forward 31 (DSCP-26)

Dynamic Host Control Protocol (DHCP)

Comcast Business equipment is configured to obtain IPv4/Host configurations via DHCP, which allows reusable IP addresses to be dynamically assigned so that endpoints can communicate with one another on the network.

You must provide a suitable DHCP server for the following Comcast Business endpoint configuration options upon bootup:

  • IP Address (IPv4)
  • Subnet Mask
  • Default Gateway
  • Domain Naming System (DNS) Server(s)
DHCP server should be configured to NOT use Option 160 or 66.

Domain Name System (DNS)

You must provide a DNS solution that can resolve public DNS records, including Naming Authority Pointer (NAPTR), Service Record (SRV), and A records.

Network & Port Address Translations (NAT & PAT)

Comcast Business VoiceEdge service works regardless of NAT or PAT setup on your network. PAT is required when using NAT functionality to ensure devices do not use identical source ports towards the Comcast Business Voice infrastructure.

Ports and Protocol settings

Comcast Business VoiceEdge service does not require you to expose any inbound IP addresses or ports to the public Internet.

Our current list of Comcast Business VoiceEdge infrastructure IP ranges and associated ports for configuration are listed here:

Protocol Transport Port(s) Purpose
HTTP TCP 80 Device Provisioning
HTTPs TCP 443 Device Provisioning
SIP TCP 5061 SIP Signaling
Device Management TCP 5222 Device Management
Device Management TCP 5223 Device Management
Device Management TCP 6800 Device Management
SIP / Device Management UDP 5060 SIP Signaling / Device Management
Device Management UDP 19305 Device Management
Media / Device Management UDP 10000 – 29999 Media / Audio
Device Management UDP 16600 – 16998 Media / Audio
DNS UDP / TCP 53 Domain Name Service
NTP UDP 123 Device Time Synchronization

WiFi Recommendations

An existing OTT customer who requires a phone in a location that cannot receive wiring can try using a Poly WiFi USB dongle. Please note that Comcast Business cannot support or diagnose 3rd party WiFi issues.

  • For use with Poly VVX 250, 350, or 450 models only
  • Works with Obi WiFi 5G USB dongles
    • Customers with Poly VVX 350 or 450 models can use a USB headset in the extra USB port (side)
  • LAN connection is automatically disabled when WiFi is enabled
  • Network details (SSID and Password)
    • WPA2-PSK network: Enter Password
    • WPA2-Enterprise network: Enter User ID and Password
  • Range plays a significant factor in voice and signaling quality. We recommend being as close as possible to your WiFi access point