Tier3

Tier3, often written as Tier III, is a term used across several industries to denote a middle level within a three-tier hierarchy. The exact meaning depends on the domain, but common usages include data center certification, IT service levels, and network classifications.

In data center design, Tier III is a certification defined by the Uptime Institute. Tier III facilities are designed to be concurrently maintainable, featuring multiple independent distribution paths and N+1 redundancy for critical systems. This configuration allows maintenance to occur without disrupting IT services. Tier III facilities typically target high availability, with an annual uptime around 99.982%, equating to about 1.6 hours of downtime per year.

In IT service management, Tier 3 represents a higher level of technical support. Tier 1 handles initial customer contact and basic issues, Tier 2 provides more in-depth troubleshooting, and Tier 3 comprises subject-matter experts or engineering staff who resolve complex problems and may coordinate with product development. Escalation to even higher levels can occur for specialized needs or fixes.

In networking and Internet infrastructure, Tier 3 networks are usually smaller regional providers that rely on upstream Tier 1 or Tier 2 networks for broader reach. They may offer transit services and peering with other networks and are perceived as a mid-tier alternative to larger backbone providers. The use of Tier 3 in this context is less formal thanTier 1 or Tier 2 designations and can vary by region and vendor.

In cloud services and software catalogs, Tier 3 can denote mid-range performance or feature levels, positioned between higher-end and lower-cost options. The exact definitions vary by vendor and product line.