What level of redundancy should be applied to network links between data centers used for disaster recovery?

Network links between data centers used for disaster recovery should have at least N+1 redundancy, where N represents the minimum number of links required to meet the bandwidth and latency requirements for replicating data and failing over critical applications. N+1 redundancy provides a backup link in case one of the primary links fails, ensuring that disaster recovery operations can continue without interruption. For highly critical applications, 2N redundancy is recommended, meaning that there are twice as many links as are minimally required. This provides even greater resilience and ensures that disaster recovery operations can proceed even if multiple links fail. The redundant links should be diverse, meaning that they should follow different physical paths and use different network providers to avoid a single point of failure. The bandwidth and latency of the redundant links should be sufficient to meet the recovery time objectives (RTOs) and recovery point objectives (RPOs) for critical applications. Regular testing of the failover process is also essential to ensure that the redundant links function as expected in the event of a disaster.