Technical Details

Welcome to Vonage SIP Trunking. Our platform enables you to seamlessly enable both inbound and outbound calls from your SIP infrastructure - with just one click, the SIP Dashboard empowers you to create a trunk and effortlessly manage it. This includes various operations such as whitelisting IPs, adding numbers, and editing/deleting SIP URIs, among other functionalities.

Concepts

This section contains some key concepts and terminology used throughout this documentation.

Endpoint

You can send your INVITE requests to the dedicated domain under Vonage regional endpoint, which is created when you set up a new trunk, for example: yourcompany.sip-us.vonage.com

Learn more about SIP endpoints.

Authentication

You can authenticate every INVITE request with Digest authentication for which you can set up a list of credentials, or create an Access Control List (ACL) to only allow certain IP addresses from your SIP infrastructure.

Recipient

Recipient numbers must be in E.164 format. See our guide on phone numbers for more information.

Caller ID

Set the Caller Line Identity (CLI) in the From header using E.164, for example: From: <447700900000@yourcompany.com>. See out phone numbers guide for more information.

Codecs

The following codecs are supported:

PCMA (G711a)
PCMU (G711u)
iLBC
g729 (without annexdb)
g722
Speex16

ACL

An Access Control List (ACL) is a set of IP ranges which are allowed to interact with a SIP System, which could be either a Vonage or customer SIP system.

Media Traffic

Visit the Vonage Knowledge Base to obtain a list of the IP ranges to open traffic for on all ports.

DTMF

Vonage supports out-of-band DTMF. For more information, see RFC4733(obsoletes RFC2833).

Health Checks

Use the OPTIONS method to run a health check on our SIP trunks.

Protocols

You can use the following protocols:

UDP on port 5060
TCP on port 5060
TLS on port 5061

Transport Layer Security (TLS) is a cryptographic protocol designed to provide communications security to your SIP connection. You can use self-signed certificates on your user agent, Vonage does not validate the client certificate. Connections using TLS 1.2 are accepted. Older protocols are disabled as they are considered insecure.

See our knowledge base article for more information on the IP addresses and port ranges to allow when using SIP trunking with the Vonage Communication APIs.

Media Protocols

You can use either Real-time Transport Protocol (RTP) or Secure Real-time Transport Protocol (SRTP) for the media exchange with Vonage. If there are security and privacy concerns, we highly recommend the use of SIP over TLS, so that the entire communication can be secured.

For outbound calls, your SIP endpoint must negotiate SRTP automatically in the standard way. For inbound calls, see configuration details below.

Note: Vonage supports a single crypto suite AES_CM_128_HMAC_SHA1_80

Session Timers

Vonage supports Session Timers RFC4028; SIP customers that require Session Timers can negotiate them at the moment of establishing a session (INVITE).