Cisco Hierarchical Model: IEEE Ethernet (MAC) Standards

Cisco Hierarchical Model: IEEE Ethernet (MAC) Standards

Layer	Examples	IEEE Number	Standard
Core	Large amounts of traffic reliably and quickly. Fault tolerance important. Don’t use VLAN, access lists or packet filtering at this layer. Cisco recommends using layer 2 switches at this layer.	802.3	Ethernet
Distribution	Provides routing, filtering and WAN access. Place to implement policies on a network (packet filtering, access lists, queuing, security and network policies, address translation, firewalls, redistribution between routing protocols, static routing, routing between VLAN and other workgroup support functions, definition of broadcast and multicast domains. Cisco recommends using routers at this layer.	802.3u	Fast Ethernet Uses MII (Media Independent Interface) and transmits using nibbles (4 bits at a time)
Access	Continued access control and policies from the distribution layer, creation of separate collision domains (and segmentation of contention networks). Cisco recommends using layer 2 switches at this layer.	802.3z	Gigabit Ethernet Uses GMII (Gigabit MII) and transmits 8 bits at a time.