Google SIP Link requirements

Requires Standard or Premiere Voice editions

With Google SIP Link, you can connect your existing carrier to Google through a set of certified Session Border Controllers (SBC). This flexibility allows you to use your existing telecommunication infrastructure and maintain uninterrupted service with your current carrier.


SIP Link connects to your SBC over a TLS connection. Media sent over the SIP trunk is encrypted using DTLS or SDES. This connection takes place through the internet or direct peering.

Supported SBC vendors

We're currently testing more SBC vendors. Check back for updates. To be considered as an SBC vendor, please email SIP Link interop ( with your SBC details.

SIP Link is currently available for the following SBC vendors. Use the integration notes to configure your devices. If you need additional help with the integration notes, contact your SBC vendor or carrier.

The minimum supported firmware versions are certified to work with SIP Link. Newer firmware versions that are a part of the same major firmware patch series are also certified.


Hardware models
  • Mediant 500
  • Mediant 500L
  • Mediant 800B/C
  • Mediant 1000B
  • Mediant 2600
  • Mediant 4000
  • Mediant 9000
  • Mediant Software SBC VE/SE/CE
Minimum supported version 7.20A.258.628
(Recommended version: 7.40A.250.262)
Media encryption
  • SDES-only for Mediant 1000B
  • SDES or DTLS for other models
External interop documentation Audiocodes interop

Audiocodes hybrid gateway

Hardware models
  • Mediant 500
  • Mediant 800B/C
  • Mediant 1000B
Minimum supported version 7.20A.258.628 
(Recommend version: 7.4)
Media encryption
  • SDES-only for Mediant 1000B
  • SDES or DTLS for other models
External interop documentation Audiocodes hybrid interop


Hardware models
  • ISR1100
  • ISR4300
  • ISR4400
  • Catalyst 8200
  • Catalyst 8300
  • Catalyst 8000V
  • ASR1000
Minimum supported version IOS XE 17.6.2 or IOS XE 17.6.4
Media encryption


External interop documentation Cisco interop


Hardware models
  • AP 1100
  • AP 3900
  • AP 4600
  • AP 6300
  • AP 6350
  • VME
Minimum supported version 8.4 and later
Media encryption SDES
External interop documentation Oracle interop


Hardware models
  • SWe Core (ver 9.2)
  • 5400
  • SWe Edge (ver 9.0.7)
  • 1000/2000
Minimum supported version 9.2 for SWe Core and 5400 models, 
9.0.7 for SWe Edge and 1000/2000 models.
Media encryption
  • SDES or DTLS for SWe Core and 5400 models 
  • SDES-only for SWe Edge and 1000/2000
External interop documentation

Firewall Ports for SIP Link

Direction Source IP Address Source Port Destination IP & port Protocol
SBC to Voice SBC Public IP Your SBC Port (signaling); 5672 TLS
SBC to Voice SBC Public IP Your SBC Port (media); 19302-19308 DTLS/SDES (udp)
Voice to SBC 5672 Customer SBC Public IP (signaling); Your SBC Port TLS
Voice to SBC 19302-19308 Customer SBC Public IP (media); Your SBC Port DTLS/SDES (udp)

Note: The TCP or UDP may change. For more info, read Voice connectivity requirements.

Install a TLS certificate certified for SIP Link

SIP Link accepts TLS certificates from the following Certificate Authorities (CAs):

  • DigiCert
  • Entrust DataCard
  • GlobalSign
  • GoDaddy
  • Sectigo

TLS certificate requirements

TLS certificates must contain the fully qualified domain name (FQDN) of the SBC as the common name (CN), be 2,048 bits in size, and use RSA or ECDSA encryption. The domain of the CN in the certificate must match the Workspace domain.

Note: Wildcard certificates are not supported.

The TLS certificate and the trust chain from either of the public CAs must be added to the TLS profile of the SBC along with the Google Root certificate. 

To get the Google Root certificate:

  1. Download Google’s trusted root CAs.
  2. Extract GTS Root R1 (GTSR1).
  3. If required, extract the GlobalSign Root CA certificate.
  4. Upload the root certificates to your SBC keystore.
  5. Enable mutual authentication for the SBC.
  6. Once the certificate is installed, check for SIP Link ping options.

TLS connection requirements

Google Voice supports TLS version 1.2 or later. Voice requires clients to send the ClientHello with at least one supported cipher to succeed cipher negotiation. Your TLS connection must support the following cipher suite:


Set up SIP Link trunk between SBC & Voice

  1. Sign in to your Google Admin console.

    Sign in using your administrator account (does not end in

  2. In the Admin console, go to Menu ""and then"" Appsand thenGoogle Workspaceand thenGoogle Voice.
  3. Click SIP Trunks and then Add a SIP trunk.
  4. Create a name for the SIP trunk and then click Continue.
  5. Click Add an SBC "" and enter the following information:
    • For SBC name, enter the name of the SBC.
    • For Host name, enter the SBC host name that matches the CN on your TLS certificate. The domain must match the Workspace domain.
    • For Model, enter the model of your SBC. Some models might not function properly with Voice. For details, go to SBC supported vendors & models
    • For TLS certificate, upload the TLS certificate signed by the trusted CA that’s associated with the SBC (must be under 5 MB).
  6. Click Save.
  7. (Optional) To add more SBCs, repeat the steps above. For high availability (HA) pairs, you must specify the active host name.
  8. Select the media encryption type for your SBCs. If you have multiple SBCs, they all must use the same encryption type. Voice accepts SDES and DTLS encryption.
  9. Click Continue.
  10. For Add a SIP header, copy the unique secret key and assign it
  11. Assign the SIP header name, X-Google-Pbx-Trunk-Secret-Key.
  12. Click Finish.

If you lose your secret key, you can find it on the SIP Trunk page by opening the SIP trunk and clicking Show secret key. When set up is complete make sure to read, Troubleshoot SIP Link setup.

Related topics

Google, Google Workspace, and related marks and logos are trademarks of Google LLC. All other company and product names are trademarks of the companies with which they are associated.

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