The functional layers for swiching environments in the Data Center are often architected around three layers, commonly referred to as The Cisco Three-Layered Hierarchical Model: The Core Layer connects the Aggregation Layers. Typically, the Core Layer utilizes high performance low latency Layer 3 switches (often 10 gig Ethernet and/or 10 gig fiber). The Aggregation Layer provides services, such as Load Balancing and SSL Optimization. Access Layer switches typically use the Aggregation Layer for connecting to the Core Layer. The Access Layer includes the hubs and switches that connect client systems.