A reliable and secure data-center. The data center includes a first data-center tier that is adapted to connect to an external network and an internal portion of the data center. A first firewall instance interfaces the first tier and the external network. A second firewall instance interfaces the first tier and the internal portion of the data center. In a more specific embodiment, the first firewall instance and the second firewall instance accommodate Internet Protocol SECurity (IPSEC) terminations using one or more VPNSMs. In this embodiment, the first data-center tier implements a core tier that includes one or more core switches that facilitate implementing the first firewall instance and the second firewall instance. The interior portion of the network represents a DeMilitarized Zone (DMZ) that includes a second tier that is connected between the first data-center tier and a third tier. The second tier implements an aggregation tier that includes one or more aggregation switches that facilitate implementing reverse-proxy caching. Overall Layer-3 design methodology is used within each tier and across tiers for optimized packet switching. The aggregation tier includes one or more aggregation-tier service modules for implementing load balancing, Secure Socket Layer (SSL) offloading, and/or the reverse-proxy caching.