Redundancy

Redundancy refers to the duplication of components or connections so that operations continue if one element fails. In networking, this covers redundant switches and routers, multiple uplinks, link aggregation, spanning tree, stacking, and protocols such as VRRP and HSRP for a resilient default gateway. In servers and data centres, redundant power supplies, fans, RAID arrays, network interface cards, cooling and power supply via UPS and backup generators are standard. Redundancy is planned according to the permissible downtime and the criticality of the applications, described through concepts such as N+1 or 2N. It is essential to avoid single points of failure along the entire path, including cabling and provider feeds. Redundancy is complemented by monitoring so that failed components are identified and replaced promptly.