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CCNA 1.5: Compare and contrast collapsed core and three-tier architectures

Overview:

The collapsed core architecture and the three-tier architecture are design approaches, not physical separations.  It’s a way of thinking about the network, not a way of viewing actual network devices.

Study Notes:

• Collapsed core
  • Core and Distribution layers are combined as a single layer
  • The collapsed core devices must be capable of core functions: high speed network connectivity and distribution functions: routing, filtering, NAT, etc.

• Three-tier is a hierarchical model:
  • Core - move large amounts of traffic as fast as possible. Majority of users
  • Distribution - routing, filtering, WAN access, NAT, firewalls, redistribution
  • Access - device connectivity
  • Three separate levels doesn’t necessarily mean three separate physical devices