Managed Tiered Security Services (MTSS) provide agencies with one of four security levels or tiers. Tiers one and two are mandatory while tiers three and four are optional.
Tier 1 service supports basic Internet connectivity and is appropriate for non-mission critical functions or non-sensitive communications. AT&T provides dedicated help desk capabilities 24 hours a day, every day for all issues concerning service delivery.
Tier 2 service provides security enhancements with additional protection from unauthorized activities and the proliferation of malicious code. It includes a combination of firewall, premises-based virtual private network (encrypted tunnels), filtering router, proxy server and boundary anti-virus detection technologies. Tier 2 is tailored to Sensitive but Unclassified (SBU) mission functions and information.
Tier 3 service includes all the security enhancements of Tier 2 and is tailored to protect extremely sensitive information up to and including National Security Information (NSI). Typical users include federal law enforcement agencies, counter-terrorism practitioners, cyber incident response teams, inter-agency collaborators and special communities of interest.
Tier 4 service is for highly sensitive telecommunication requirements typically designated as “Special Category,” protecting critical functions while ensuring the highest levels of performance, survivability, and resistance to external compromise. Tier 4 services are tailored to meet general and national level guidance for the processing of NSI classified functions such as Top Secret, Sensitive Compartmented Information(SCI)and Single Integrated Operational Plan – Extremely Sensitive Information (SIOP-ESI).