LiveKit docs › Get Started › Provider-specific quickstarts › Sinch --- # Create and configure a Sinch SIP trunk > Step-by-step instructions for creating inbound and outbound SIP trunks using Sinch Elastic SIP Trunking. Connect [Sinch Elastic SIP Trunking](https://developers.sinch.com/docs/est/) with LiveKit for inbound and outbound calls. Sinch Elastic SIP Trunking uses static endpoint routing for inbound calls and ACL-based or digest-based authentication for outbound calls. ## Prerequisites The following are required to complete the steps in this guide: - A [Sinch account](https://www.sinch.com/) with Elastic SIP Trunking access. - A purchased [phone number (DID)](https://dashboard.sinch.com/numbers/your-numbers) from Sinch. - A [LiveKit Cloud project](https://cloud.livekit.io/projects/p_/settings/project). ## Create and configure SIP trunk Complete the following steps to create and configure your SIP trunk. > ❗ **Wait for changes to propagate** > > After changing endpoints, ACLs, or other routing settings in the Sinch dashboard, wait at least 60 seconds before testing to allow changes to propagate. 1. Sign in to the [Sinch dashboard](https://dashboard.sinch.com/). 2. Select **Voice** → **Elastic SIP Trunking** → **Trunks**. 3. Select **Create new SIP trunk**. 4. Complete the **SIP trunk Name** and **Domain name** fields. 5. Select **Create Trunk**. Continue with the following sections to set up inbound and outbound calling. ### Inbound call settings Add a static endpoint to your Elastic SIP Trunking trunk that routes inbound calls to your LiveKit SIP endpoint. 1. Sign in to the [Sinch dashboard](https://dashboard.sinch.com/). 2. Select **Elastic SIP Trunking** → [**Trunks**](https://dashboard.sinch.com/trunks/your-trunks) and select your trunk. 3. In the **SIP Endpoints** section, select **Add an Endpoint**. 4. Enter a **Name** for the endpoint. For example, "My LiveKit endpoint." 5. For **IP Address/FQDN**, enter your LiveKit [SIP endpoint](https://docs.livekit.io/telephony/start/sip-trunk-setup.md#sip-endpoint). For example, `vjnxecm0tjk.sip.livekit.cloud`. > ℹ️ **Region-based endpoints** > > To restrict calls to a specific region, replace your global LiveKit SIP endpoint with a [region-based endpoint](https://docs.livekit.io/telephony/features/region-pinning.md). 6. For **Port**, enter `5060`. 7. For **Protocol**, select `TCP`. > ℹ️ **Secure trunking** > > If you're setting up [secure trunking](https://docs.livekit.io/telephony/features/secure-trunking.md), use port `5061` and protocol `TLS` instead. 8. Select **Create**. ### Outbound call settings Sinch Elastic SIP Trunking supports IP-based ACL authentication and digest-based authentication for outbound calls. Configure your preferred method in the Sinch dashboard: 1. Sign in to the [Sinch dashboard](https://dashboard.sinch.com/). 2. Select **Elastic SIP Trunking** → [**Trunks**](https://dashboard.sinch.com/trunks/your-trunks) and select your trunk. 3. In the **Outbound call settings** section, configure the authentication method for outbound calls: - **ACL-based:** Add an ACL entry for the [LiveKit Cloud IP ranges](https://docs.livekit.io/deploy/admin/firewall.md#static-ips). - **Digest-based:** Set up a username and password for SIP digest authentication. > ℹ️ **Note** > > For LiveKit Cloud IP ranges, check your [project settings](https://cloud.livekit.io/projects/p_/settings/project) or contact [LiveKit support](https://livekit.io/contact). ### Assign a phone number to the trunk In the **Phone numbers** section, select **Assign Numbers** and select the phone number you want to assign to the trunk. ## Next steps: LiveKit setup Finish connecting your SIP trunk to LiveKit using the main setup documentation. - **[SIP trunk setup](https://docs.livekit.io/telephony/start/sip-trunk-setup.md#livekit-setup)**: Configure your Telnyx trunk in LiveKit. ## Troubleshooting If calls fail to connect, check the following common issues. ### Inbound calls don't reach LiveKit - Verify the static endpoint in your Sinch trunk points to the correct LiveKit SIP endpoint and port. See [Inbound call settings](#inbound) for more information. - Confirm the phone number is assigned to the trunk. See [Assign a phone number to the trunk](#assign-phone-number) for more information. - Check that the endpoint hasn't been recently changed. Allow at least 60 seconds for changes to propagate. ### Outbound calls fail - Verify the authentication method and configuration. If using ACL-based auth, confirm the ACL includes the correct LiveKit Cloud IP addresses. If using digest auth, verify the username and password credentials match. See [Outbound call settings](#outbound) for more information. - Check that the caller ID is in E.164 format and that the phone number is assigned to your Sinch trunk. See [Assign a phone number to the trunk](#assign-phone-number) for more information. ### One-way audio One-way audio is typically caused by NAT or firewall issues affecting RTP media. Verify your Sinch trunk configuration allows bidirectional media. See [Elastic SIP Trunking test plan](https://developers.sinch.com/docs/est/test-plan). ### Additional troubleshooting For additional troubleshooting help, see the [SIP troubleshooting guide](https://docs.livekit.io/reference/telephony/troubleshooting.md) and the [Sinch Elastic SIP Trunking integration guide](https://developers.sinch.com/docs/est/integration-guides/livekit). ## Additional resources The following guide provides validation instructions for Sinch Elastic SIP Trunking. - **[Sinch Elastic SIP Trunking test plan](https://developers.sinch.com/docs/est/test-plan)**: Validation steps for your Sinch Elastic SIP Trunking inbound and outbound setup. --- This document was rendered at 2026-06-07T11:35:50.757Z. For the latest version of this document, see [https://docs.livekit.io/telephony/start/providers/sinch.md](https://docs.livekit.io/telephony/start/providers/sinch.md). To explore all LiveKit documentation, see [llms.txt](https://docs.livekit.io/llms.txt).