Set the limit of maximum contacts in a queue using Amazon Connect

By default a queue can contain up to your service quota for voice, chat, tasks, and email:

• Concurrent active calls per instance

• Concurrent active chats per instance (includes SMS)

• Concurrent active tasks per instance

• Concurrent active emails per instance

To increase one of these quotas, you must request a quota increase. For more information, see Amazon Connect service quotas.

There may be situations where you want a specific queue to allow fewer contacts than the allowed quota. For example:

• You have a queue that is dedicated to calls about complicated issues that take an average of 15 minutes to resolve, you may want to limit the number of calls allowed in the queue to be less than Concurrent active calls per instance. This prevents customers from waiting for hours.

• You may have a queue dedicated to chats. Your service quota is 100 but you want only up to 20 chats at a time. You can set that value so Amazon Connect limits the number of active chats routed to that queue.

• You have a queue that combines more than one channel, and you set a custom value. Note that the queue stops accepting new contacts after that number is reached, regardless of the distribution of contacts. For example, if you set the value to 50, and the first 50 contacts are chats, then voice calls are not routed to this queue.

This topic explains how to reduce the allowed number of contacts in a queue for these situations.

Reduce the number of contacts allowed in a queue

To reduce the number of contacts allowed in a standard queue at the same time, you set the Maximum contacts in queue limit for the standard queue. This setting does not apply to agent queues; those are always limited to 10 contacts.

When you enter a number in Maximum contacts in queue, Amazon Connect validates that the number is less than the sum of your concurrent active contacts service quotas: Concurrent calls per instance + Concurrent active chats per instance + Concurrent active tasks per instance + Concurrent active emails per instance.

Important

• You must set Maximum contacts in queue to be less than the sum of the following quotas combined: Concurrent calls per instance + Concurrent active chats per instance + Concurrent active tasks per instance + Concurrent active emails per instance.

• Incoming calls and queued callbacks count towards the queue size limit.

For information about default service quotas and how to request an increase, see Amazon Connect service quotas.

To reduce the number of contacts allowed in a specific queue

1. On the navigation menu, choose Routing, Queues, Add new queue. Or, edit an existing queue.

2. In Maximum contacts in queue, choose Set a limit across all channels. If the queue is also used for chats, tasks, and email, then all channels will be capped at the same maximum.

3. In the box, specify how many contacts can be in the queue before it's considered full. The value cannot exceed the sum of Concurrent active calls per instance + Concurrent active chats per instance + Concurrent active tasks per instance +Concurrent active emails per instance.

   

What happens to calls when a queue is full

• Incoming calls: Ideally you've set up queued callback, or have another contingency implemented. If not, the next incoming call gets a reorder tone (also known as a fast busy tone), which indicates no transmission path to the called number is available.

• Queued callbacks: The next queued callback is routed down the error branch.

What happens if Maximum contacts in queue is set to 0

If you set Maximum contacts in queue to 0 it renders the queue unusable. The behavior is the same as when a queue is full.

Queue maximum limit exceptions

There are times when you can add more contacts to a queue than the set Maximum contacts in queue limit.

• There may be a slight delay between the time that a queue reaches its capacity limit and when this limit is enforced in the flow. This delay could cause incoming contacts to be queued during that time, particularly during bursts of traffic.

Additionally, Amazon Connect includes a 20 percent buffer to the queue capacity for the following exceptional scenarios:

• A contact was transformed into a Queued Callback, scheduled to be added to the queue at X time using the Initial delay setting in the flow. However, when the scheduled time arrived, the target queue had reached its Maximum capacity in queue limit. In this scenario, Amazon Connect allows the Queued Callback to be enqueued up to a 20 percent buffer of the Maximum capacity in queue limit for the queue.

• A contact, previously queued in Queue1, is now being transferred to Queue2 through the flow. However, when the transfer is attempted, Queue2 has already reached its Maximum capacity in queue limit. In this scenario, Amazon Connect allows the transfer to proceed, up to a 20 percent buffer of the Maximum capacity in queue limit for Queue2.

• An agent initiates a manual transfer of a contact into a queue through quick connects. However, when the transfer is attempted, the queue has already reached its Maximum capacity in queue limit. In this scenario, Amazon Connect allows the transfer to proceed, up to a 20 percent buffer of the Maximum capacity in queue limit.