Each Open Connect Appliance (OCA) stores a portion of the Netflix catalog, which in general is less than the complete content library for a given region. Popularity changes, new titles that are added to the service, re-encoded movies, and routine software enhancements are all part of the nightly updates, or fill, that each appliance must download to remain current.
Fill windows
By design, OCAs follow a “push fill” methodology. They primarily fill every day during a window of time that corresponds to your off-peak hours. The timing of the fill window is defined in partnership with your network planning team.
The goal is to set the fill window such that:
- It occurs during the trough of your Netflix traffic
- It does not disrupt your inbound traffic peaks
Setting the fill window this way allows the system to continue to download updates and serve clients without negatively impacting playback performance.
Requirements for the fill window, by hardware type:
| Setting | Storage | Global |
| Length of time | 12 hours | 12 hours |
| Timeframe | 2AM to 2PM (local time) (can be shifted +/- 2 hours)* | 2AM to 2PM (local time) (can be shifted +/- 2 hours)* |
| Bandwidth | Maximum rate of 1.2 Gbps per appliance | Maximum rate of 0.4 Gbps per appliance |
| Total traffic during fill window | Up to 6.5 TB | Up to 2.1 TB |
*All OCAs within a site must begin filling at the same time.
The system might complete filling before the end of the fill window, and it might fill more than once if new content becomes available before the fill window ends.
Fill patterns
In general, appliances determine where to receive fill using selection criteria that is similar to the steering criteria that is used by Netflix client devices. The following scenarios provide more detail.
If you have specific fill requirements, discuss them with your partner engagement manager during the initial site design process. If you require changes to your appliance’s fill behavior post-deployment, open a ticket.
Peer filling
OCAs will attempt to peer fill from each other in either of these two cases:
- If they are clustered
- If they are on the same subnet
For example, assume that in the following diagram, OCA #1 and OCA #2 are in a cluster. If OCA #1 downloads a movie via a regular cache fill, OCA #2 will then seek to download the movie from OCA #1 instead of via transit or Open Connect peering. Routes to the OCAs must be advertised over Open Connect peering to ensure that the peering session is used for fill traffic.
Tier Filling
Peer filling is the most efficient method, however as a second-best option tier filling is considered. OCAs that can see each other’s IP address in their BGP feed (but are not in the same cluster or subnet) will consider filling from each other rather than via a regular cache fill.
To identify tier fill issues within your network, you can run the Tier Fill report in the Partner Portal Route Explorer tool.
Out-of-cycle fills
There will be cases that cause a need to deploy or update files on the OCAs outside of the normal fill window. This need can arise for various reasons, for example:
- If re-encoding of a popular title is required to repair viewing issues
- To make a new, “day-of-broadcast”, or “day-after-broadcast” title available
- During live events
When these out-of-cycle fills occur, you will see fill traffic outside of the configured fill window.
See also: This blog post about fill