> ## Documentation Index
> Fetch the complete documentation index at: https://plivo.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# India Concurrency Limits

> Understand and manage concurrent call limits for India accounts

<Note>
  This page covers concurrency limits specific to India. For global account limits (CPS, API rate limits, feature limits), see [Account and feature limits](/voice/concepts/account-limits/).
</Note>

<Info title="TL;DR">
  * **Default concurrency limit:** 50 concurrent calls
  * **What counts:** All PSTN calls (inbound and outbound, across Voice API and SIP trunking)
  * **CPS relationship:** CPS = concurrency limit ÷ 25 (default 2 CPS)
  * **Exceeding the limit:** Calls are rejected instantly — no queuing, no grace period
  * **To increase:** Raise a ticket with [Plivo support](https://support.plivo.com)
</Info>

<Warning>
  **Hard enforcement is active from April 20, 2026.** Calls that exceed your concurrency limit fail instantly with no queuing or grace period. Review your usage and [increase your limit](#how-to-increase-your-limit) if needed.
</Warning>

For India, your account has both a concurrency limit and a CPS limit. The concurrency limit is the maximum number of calls that can be active simultaneously — calls that exceed this limit are rejected immediately.

***

## What Is Concurrency?

Concurrency is the number of active calls at any given point in time. This includes calls in all active phases — not just fully connected calls.

| Call State                  | Description                           | Counted? |
| --------------------------- | ------------------------------------- | -------- |
| **Ringing / Connecting**    | Call initiated and in the setup phase | Yes      |
| **Connected / In-progress** | Call is live and voice is flowing     | Yes      |
| **Completed / Ended**       | Call has been disconnected            | No       |

All PSTN calls — inbound and outbound, across Voice API and SIP trunking — count toward your concurrency limit.

***

## How Your Limit Works

Your account has a default concurrency limit of 50 concurrent calls. CPS (Calls Per Second) is derived from your concurrency limit:

**CPS = Concurrency Limit ÷ 25**

For example, an account with a concurrency limit of 100 has a CPS of 4 (100 ÷ 25).

| Concurrency Limit | CPS |
| ----------------- | --- |
| 50 (default)      | 2   |
| 100               | 4   |
| 250               | 10  |
| 500               | 20  |

<Note>
  Both limits apply simultaneously. The concurrency limit caps how many calls can be active at once. CPS caps how fast you can start new calls.
</Note>

***

## What Happens When You Exceed the Limit

When your active call count reaches the concurrency limit, any new call attempt is rejected immediately.

| Scenario                             | Outcome                                                                                |
| ------------------------------------ | -------------------------------------------------------------------------------------- |
| Call attempt while under limit       | Call proceeds normally                                                                 |
| Call attempt that would breach limit | Call fails immediately — no ring, no connection                                        |
| Subsequent calls while at the limit  | Continue to fail until active calls drop below the concurrency limit                   |
| Recovery                             | As soon as active calls drop below the concurrency limit, new calls are accepted again |

<Warning>
  There is no queuing and no grace period. Calls are rejected the moment they would breach the limit.
</Warning>

### Error Codes

| Product   | Code   | Reason                           |
| --------- | ------ | -------------------------------- |
| Voice API | `5030` | `Concurrency Limit Breached`     |
| Zentrunk  | `5190` | `concurrent_call_limit_exceeded` |

For Voice API calls, error code `5030` is returned in two places:

* **API response** — returned immediately when the call attempt is rejected
* **Hangup URL callback** — delivered to your hangup URL

***

## How to Check Your Usage

You can view concurrency data directly from the [Plivo console](https://cx.plivo.com/home):

1. Navigate to **Voice > Call Logs > Export > Export Concurrency Data**.
2. The export provides minute-level concurrent call data for up to 30 days.

<Info>
  **Rule of thumb:** If your 30-day peak concurrent call count exceeds 80% of your concurrency limit, we recommend reviewing your capacity and increasing your limit before you experience call failures.
</Info>

***

## Recommendations to Manage Concurrency

Follow these best practices to avoid hitting your concurrency limit unexpectedly:

1. **Monitor your peak usage regularly.** Export concurrency data from the [Plivo console](https://cx.plivo.com/home) and review your 30-day peak. If your peak exceeds 80% of your limit, consider increasing your limit.

2. **Stagger outbound campaigns.** If you run bulk outbound calls, spread them over time rather than launching all at once. This keeps your concurrent call count well below the limit.

3. **Handle errors gracefully.** When a call is rejected with error code 5030, implement retry logic with a short delay. Wait for active calls to complete before retrying.

4. **Optimize call duration.** Shorter calls free up concurrency slots faster. Review your call flows to ensure calls are not staying connected longer than necessary.

5. **Plan for traffic spikes.** If you expect seasonal or event-driven traffic increases, increase your concurrency limit in advance by raising a ticket with [Plivo support](https://support.plivo.com).

***

## How to Increase Your Limit

To increase your concurrency limit, raise a ticket with [Plivo support](https://support.plivo.com). Your CPS adjusts automatically — every additional 25 concurrent call slots adds 1 CPS.

| Detail            | Value                                                          |
| ----------------- | -------------------------------------------------------------- |
| What changes      | Your account's concurrency limit                               |
| Minimum increment | 25 concurrent call slots (adds 1 CPS)                          |
| How to request    | Raise a ticket with [Plivo support](https://support.plivo.com) |

***

## FAQ

***

### My usage sometimes spikes — what should I do?

Review the 30-day peak in your concurrency export to understand worst-case scenarios. If your peak is close to your limit, add a safety buffer by increasing your concurrency limit to avoid call failures during traffic spikes.

***

### How do concurrency and CPS relate?

CPS is derived from your concurrency limit. For every 25 concurrent call slots, you get 1 CPS. Both limits apply simultaneously — concurrency caps how many calls can be active at once, and CPS caps how fast you can start new calls.

***

## Related Resources

* [Account limits](/voice/concepts/account-limits/) — CPS and rate limits overview
* [Voice API hangup causes](/voice/troubleshooting/hangup-causes/) — Error code reference
* [Zentrunk hangup codes](/sip-trunking/troubleshooting/zentrunk-hangup-codes/) — SIP trunking error codes