# Zoom Phone Local Survivability Field Guide

### Introduction

Zoom Phone is a cloud-based telephony service that is dependent on internet provider connectivity to Zoom’s data centers to operate. However, maintaining telephony services in the event of an internet service failure or a service impacting event is critical for business continuity and operations. To address this, Zoom offers the Zoom Phone Local Survivability (ZPLS) module as a [Zoom Node](#_a2lvsihjp0ek) workload to provide telephony resiliency in the event of an internet outage.

During a survivability event, users register to the ZPLS module, which provides basic telephony services — like internal calling — until full service can be restored. Customers can expand this functionality by integrating the ZPLS module with an on-premises private branch exchange (PBX) system or a customer-provided carrier (BYOC) to route calls across the public switched telephone network (PSTN).

When integrated with an SBC, businesses have the best of both worlds: the simplicity and ease of a cloud-managed phone system, with the survivability and resiliency of on-premises infrastructure when the unforeseen occurs. With ZPLS, businesses can comfortably deprecate *most* legacy, on-premises telephony appliances and migrate to a cloud-based phone system with confidence.

To that end, this guide provides a comprehensive overview and deployment flow to the ZPLS module, including product installation and deployment, design and implementation considerations, feature support, use cases, and more.

### How to Use This Guide

This guide is designed to provide you information in bite-size chunks that makes learning a new product easier. Instead of offering long, tedious paragraphs packed full of information, we have broken content down into shorter summaries, with elaborations in the body for additional information or context.

For example, you will read that, “ZPLS is an on-premises virtual appliance that supports internal phone calls between users in a common site when Zoom data centers are unreachable.” If that statement makes sense to you on its own, you can feel free to skip the text underneath the summary and move onto the next, where you will read, “ZPLS also supports cross-site calling when ZPLS appliances and their associated sites are connected through a common network.”

When you combine these summaries, the bigger picture begins to form:

* *ZPLS is an on-premises virtual appliance that supports internal phone calls between users in a common site when Zoom data centers are unreachable.*
* *ZPLS also supports cross-site calling when ZPLS appliances and their associated sites are connected through a common network.*

If these summaries provide you enough information to understand the product—great! But if you want to know more, there’s additional context and information available underneath each summary.

The full list of pages within this guide follow below and can be visited out of order, if you know which specific content you're looking for:

{% content-ref url="/pages/jMHUVpUc6s7Lerg8771O" %}
[Overview](/zoom-workplace/zoom-phone/zoom-phone-local-survivability-field-guide/overview.md)
{% endcontent-ref %}

{% content-ref url="/pages/WwhX7I00HYNDBqJhmqXF" %}
[Before You Begin](/zoom-workplace/zoom-phone/zoom-phone-local-survivability-field-guide/before-you-begin.md)
{% endcontent-ref %}

{% content-ref url="/pages/bPzHBir9YapG54VaMPRp" %}
[Deploy the ZPLS Module](/zoom-workplace/zoom-phone/zoom-phone-local-survivability-field-guide/deploy-the-zpls-module.md)
{% endcontent-ref %}

{% content-ref url="/pages/mJVriyLRmtjOieB8G22H" %}
[Configure ZPLS for Your Account](/zoom-workplace/zoom-phone/zoom-phone-local-survivability-field-guide/configure-zpls-for-your-account.md)
{% endcontent-ref %}

{% content-ref url="/pages/VuHvvQwWkrcjRbIsr62x" %}
[Initialize the ZPLS Module](/zoom-workplace/zoom-phone/zoom-phone-local-survivability-field-guide/initialize-the-zpls-module.md)
{% endcontent-ref %}

{% content-ref url="/pages/ihU2IkIXTllhWZp3oZgX" %}
[Confirm the ZPLS Module is Operational](/zoom-workplace/zoom-phone/zoom-phone-local-survivability-field-guide/confirm-the-zpls-module-is-operational.md)
{% endcontent-ref %}

{% content-ref url="/pages/FTHFXr5lZ8Wl8eKIJjhG" %}
[Enable Users for ZPLS](/zoom-workplace/zoom-phone/zoom-phone-local-survivability-field-guide/enable-users-for-zpls.md)
{% endcontent-ref %}

{% content-ref url="/pages/7WiAcrXg49jQDguXIUy1" %}
[Optional Tasks](/zoom-workplace/zoom-phone/zoom-phone-local-survivability-field-guide/optional-tasks.md)
{% endcontent-ref %}

{% content-ref url="/pages/HXJnx68lECziRchCmxE2" %}
[Troubleshooting](/zoom-workplace/zoom-phone/zoom-phone-local-survivability-field-guide/troubleshooting.md)
{% endcontent-ref %}


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# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://library.zoom.com/zoom-workplace/zoom-phone/zoom-phone-local-survivability-field-guide.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.