Core Layer
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The Core Layer in traditional networks:
- Responsible for fast packet forwarding between distribution layer devices
- Contains high-speed routers designed for reliability and speed
- Has both control plane and data plane tightly coupled within each router
- Each router makes its own forwarding decisions based on local routing tables
- Exchanges routing information with other routers using protocols like OSPF or BGP
Distribution Layer
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The Distribution Layer in traditional networks:
- Acts as a boundary between access and core layers
- Implements policies for routing, filtering, QoS, etc.
- Each switch contains its own control plane and data plane functionality
- Routing and switching decisions are made locally within each device
- Communicates with other devices through various routing and spanning tree protocols
Access Layer
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The Access Layer in traditional networks:
- Provides connectivity to end devices (computers, printers, etc.)
- Typically consists of Layer 2 switches
- Each switch has its own control plane for making local forwarding decisions
- Uses spanning tree protocol to prevent loops
- Limited intelligence - mostly follows instructions from distribution layer