# Cumulative Capacity Utilization (CCU) for a node

When an order is optimized, the Optimization service considers the backlog at a ship node to decide whether it is used to fulfill the order.

The backlog calculation considers the following components:
• The node capacity consumed, which is provided as input in the request to the Optimizer API call.
• The node capacity available, which is provided as capacity data.
• The local time zone of the ship node, which is provided as the fulfillment network.

To calculate the backlog, the local time zone of the ship node is considered along with the capacity data for the present and subsequent days. The backlog that is decremented for each consecutive day until no backlog remains is referred to as Cumulative Capacity Utilization (CCU).

In the following examples, the time zone for the provisioned account is Pacific Standard Time (PST) and the time zone of ship node Matrix-Store1 is Eastern Standard Time (EST).

 Store 1 May 2020 2 May 2020 3 May 2020 4 May 2020 5 May 2020 6 May 2020 7 May 2020 8 May 2020 9 May 2020 Matrix-Store1 50 60 185 250 300 400 150 60 70

## Example 1

The node capacity that is consumed at ship node `Matrix-Store1` is 40.0 when the order is optimized at 2020-05-01T07:00:00 PST. The local time at `Matrix-Store1` is 2020-05-01T10:00:00 EST. The capacity data is available starting 1 May 2020.

In this example, the node capacity that is consumed is 40 and the capacity data on 1 May 2020 is 50. The CCU is calculated as (40/50) = 0.8 and the backlog is 0.

## Example 2

The node capacity that is consumed at ship node `Matrix-Store1` is 1036.0 when an order is optimized at 2020-05-01T10:00:00 PST. The local time at `Matrix-Store1` is 2020-05-01T13:00:00 EST. The backlog calculation starts on 1 May 2020.

In this example, the node capacity that is consumed is 1036. The backlog days and CCU date-wise calculation is the following:

1 May 2020: 1036 – 50 = 986 Backlog = 1 CCU = 1

2 May 2020: 986 – 60 = 926 Backlog = 2 CCU = 2

3 May 2020: 926 – 185 = 741 Backlog = 3 CCU = 3

4 May 2020: 741 – 250 = 491 Backlog = 4 CCU = 4

5 May 2020: 491 – 300 = 191 Backlog = 5 CCU = 5

6 May 2020: On this day, the remaining 191 can be fulfilled completely, then (191)/400 = 0.4775

 Backlog 5 5.4775

## Example 3

The node capacity that is consumed at ship node Matrix-Store1 is 1036.0 when an order is optimized at 2020-05-01T22:00:00 PST. The local time at Matrix-Store1 is 2020-05-02T01:00:00 EST. The backlog calculation starts on 2 May 2020.

 Date Backlog CCU 1 May 2020 2 May 2020 3 May 2020 4 May 2020 5 May 2020 6 May 2020 7 May 2020 8 May 2020 9 May 2020 – 1 1 1 1 0 – 1 1 1 1 0.6025

In this example, the node capacity that is consumed is 1036. The following is the backlog days and CCU date-wise calculation:

2 May 2020: 1036 – 60 = 976 Backlog = 1 CCU = 1

3 May 2020: 926 – 185 = 791 Backlog = 2 CCU = 2

4 May 2020: 741 – 250 = 541 Backlog = 3 CCU = 3

5 May 2020: 491 – 300 = 241 Backlog = 4 CCU = 4

6 May 2020: On this day, the remaining 241 can be fulfilled completely, then (241)/400 = 0.6025

 Backlog 4 4.6025