Netflix traffic is steered to OCAs based on your BGP announcements to the appliance, as described in detail in the Network Configuration article.
Managing imbalances within a site
When all appliances in a cluster do not receive identical BGP route advertisements, they cannot stream as much content as would otherwise be possible. As a result, your customers are forced to stream from offsite caches for some percentage of their streaming requests.
You can view the current BGP advertisements that you are sending to each OCA on the Route Explorer page in the Partner Portal. You manage BGP route advertisements on your router.
To resolve a BGP imbalance issue, ensure that all of the appliances in each site or manifest cluster are receiving identical BGP route advertisements. You can preference some appliances over others by using BGP MED (multi-exit discriminator) assignments.
In some cases, you may need to ensure that all members of a cluster have IPv6 addresses and BGP sessions configured for IPv6.
Managing imbalances across sites
To enable efficient nightly fill: If you have separate clusters that are located in two different sites, ensure that the appliances within one cluster can hear the subnets for the appliances in the other cluster via the BGP connection that is established with your router. See the Fill patterns article for more details.
To optimize route announcements across peering and embedded sites, use the Route Optimizer.