Tier-0 IT Support level, also called as Level-0 IT support, is usually the automated machine interactive support level. There is little or no scope for immediate human interaction when receiving support.
Tier-1 support or Level 1 support represents a very basic level of support service, usually provided by IT personnel having the lowest level of skills and access levels.
Tier-2 support level is for providing in-depth troubleshooting, technical analysis, and support from the backend.
Tier-3 Is a level consisting of SMEs (Subject Matter Expert) on the product or service your organization is providing support to. The Tier-3 technicians attempt to reproduce problems in the lab environment and tried to find the root cause, using product code, designs, or specifications. Once the root cause is identified, the fixes to the issues are documented and communicated to Tier-1 and Tier-2 technicians as a future reference.
Tier-4 support usually refers to outside support teams who provide support to the services that are not directly supported by the organization.
Many companies tailor this hierarchy and combine support tiers (levels) according to their resource capacity, financial capability, and philosophies. In some organizations, Tier-1 and Tier-2 functional groups are handled by the same technicians while other organizations may prefer to combine Tier-2 and Tier-3 functions in the same groups.
The ultimate goal is to automate as many support functions as possible in Tier-0 where end users can quickly and easily find solutions without IT personnel's help. This saves the higher skilled resources for creating new solutions, troubleshooting difficult problems, and also reduces the operational cost.
| IT Support Level | Function | Support methodology | Staffing needs |
| Tier 0 | Self-help and user-retrieved information | Users retrieve support information from web and mobile pages or apps, including FAQs, detailed product and technical information, blog posts, manuals, and search functions. Users also use apps to access service catalogs where they can request and receive services without involving the IT staff. Email, web forms, and social contact methods such as Twitter, LinkedIn, etc., are used to send questions and requests to upper support tiers or company personnel. Customer forums allow users to crowdsource solutions, usually without input from company personnel. | Tier 0 requires technical and marketing resources to create, maintain, and update product information. A development team handles web site and app creation. Moderators are used to monitor customer forums. Tier 1 personnel respond to requests received through email, web sites, or social media. |
| Tier 1 | Basic help desk resolution and service desk delivery | Support for basic customer issues such as solving usage problems and fulfilling service desk requests that need IT involvement. If no solution is available, tier 1 personnel escalate incidents to a higher tier. | Lower-level technical personnel, trained to solve known problems and to fulfill service requests by following scripts. |
| Tier 2 | In-depth technical support | Experienced and knowledgeable technicians assess issues and provide solutions for problems that cannot be handled by tier 1. If no solution is available, tier 2 support escalates the incident to tier 3. | Support personnel with deep knowledge of the product or service, but not necessarily the engineers or programmers who designed and created the product. |
| Tier 3 | Expert product and service support | Access to the highest technical resources available for problem resolution or new feature creation. Tier 3 technicians attempt to duplicate problems and define root causes, using product designs, code, or specifications. Once a cause is identified, the company decides whether to create a new fix, depending on the cause of the problem. New fixes are documented for use by Tier 1 and Tier 2 personnel. | Tier 3 specialists are generally the most highly skilled product specialists, and may include the creators, chief architects, or engineers who created the product or service. |
| Tier 4 | Outside support for problems not supported by the organization | Contracted support for items provided by but not directly serviced by the organization, including printer support, vendor software support, machine maintenance, depot support, and other outsourced services. Problems or requests are forwarded to tier 4 support and monitored by the organization for implementation. | Preferred vendors and business partners providing support and services for items provided by your company. |
Source:
https://www.bmc.com/blogs/support-levels-level-1-level-2-level-3/
https://www.certguidance.com/explaining-support-levels-itil-itsm/
