PBX integration guide




To help you configure your PBX, we've compiled some unique settings to keep in mind during your onboard. In this article, we'll go over our network, IP requirements, SIP signaling, dial plans, and more. Let's get started!

SBC IP information

Bandwidth employs a pair of SBCs (Session Border Controllers) for signaling redundancy. For termination services, please ensure that both IP addresses provided are configured for inbound traffic in your PBX as Bandwidth will be using both IPs to pass calls to your switch. Your Implementation Specialist will be provide these IP addresses during the onboarding kickoff call and via the welcome email. Please let us know if you need these IPs again.


Bandwidth SIP (Session Initiation Protocol) signaling protocol is designed for RFC3261. If any other method is used, calls will fail to set up. 

Allowed ports for media and audio

If your PBX is protected by a firewall, the manufacturer compliance will need to be verified that the firewall has the ability to act as either a SIP ALG or a Back-to-Back User Agent (B2BUA). The following ports are required to allow for full 2-­way audio:

  • UDP port 5060 – must be opened to support SIP signaling and is the default port for Bandwidth.
  • UDP ports 1024-­64,000 – must be opened either statically or dynamically (ALG) to allow for audio path.
  • Bandwidth will use multiple IP addresses to allow media from its gateways.

Outbound traffic

When sending outbound traffic to Bandwidth from your PBX, here are a few things to keep in mind:

  • We accept traffic based on whitelisted IPs. Please ensure you have provided your implementation specialist with your IPs. If these have updated or changed after your onboard, please open a support ticket and we'll whitelist your new IPs. We'll reject traffic from non-authorized IPs.
  • Bandwidth doesn't use a Username/Password to authentic traffic. We only authenticate via trusted IPs. If your PBX interface is asking for this or credentials/registration, please ensure registration is disabled or bypassed per the recommended instructs from your PBX provider. 
  • With outbound traffic, please be able to failover on a variety of SIP Error Codes to our Geo-Redundant access point in the event your target access point is unavailable.   


The following attributes are allowed within Bandwidth SIP trunks:

  • DTMF
  • Dial Plans
  • Codecs
  • Signaling Protocol
  • IP Protocol
  • Media Anchoring

Supported DTMF

Bandwidth supports both in-­band and out-­of-­band DTMF outlined in RFC2833.

Dial plans

Bandwidth supports E.164 for outbound calling only and is the default dial plan for our SIP Trunking Product. E.164 is an internationally recognized standard characterized by a "+" followed by the country code, then the phone number. For example:

Local & Long Distance: +19192971000

International: +4402074942020

Please ensure your PBX is configured to send and receive in the E.164 format.

IP protocols

Bandwidth requires that all SIP and audio be delivered via UDP, in packets no larger than 1350 bytes. TCP is not supported.

Supported codecs

The following codecs are supported by Bandwidth:

  • G711ulaw, G729a, ILBC (will default to ptime 30)
  • G711ulaw, G729a  (will default to ptime 20)

Call concurrency

In regards to our SIP Trunking product, 1 Trunk = 1 Bi-Direction Trunk. For example, 5 Trunks can support 3 inbound calls and 2 outbound calls, totaling 5 pathways. To purchase additional trunks, please reach out to your Account Manager. Not sure who your Account Manager is? Please open a ticket with your Bandwidth Support Team or hit us up at (855) 864-7776!

Supported caller ID and privacy types

  • FROM field – default option for caller ID name, number, and rating.
  • RPID (Remote Party ID) – secondary option
  • P-­Asserted ID – supported option
  • Privacy Headers – supported option

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