Three Tier Architecture (Networking) or Hierarchical LAN Network Model
- Access Layer
- Distribution Layer
- Core/Backbone Layer
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| Fig:1 |
Access Layer: (Switches/L2)
Provides work-group/users access to the network. Features includes:
- Highly Available
- Broadcast suppression
- Fully Redundant
- Highly Scalable
- No Single point of failure (NSPOF)
Functions:
- Access Capability (Connectivity)
- Port Security
- VLAN creation
- L2 access security
- Spanning tree
Distribution Layer:(Routers/Switches/L3)
Most important layer is Distribution because maximum traffic management will happen in the same building so maximum work load on Distribution Layer.
Provides policy based connectivity and controls the boundary. Features & Functions includes:
- Maximum Traffic Manipulation - Manage & Handling traffic
- Route and VLAN aggregation
- Inter-VLAN routing
- Filtering and Security (ACL)
- Trunk termination
- Redundancy and Load Balancing
- QoS
Core Layer: (All to All Connectivity)
- Fast (High Speed) Switching
- L2 Transport only
- No Traffic Manipulation
- High Reliability
- Fault Tolerance
- QoS
Process:
Very Important: Bring as much L3 switching/Routing as possible to control broadcast and void VLAN in your design because VLAN is use for security, separation and management.
Following diagram describe High Available, Secure, Better QoS and Highly Scalable design.
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| Fig:2 |
★CT21
Reference: https://rstforum.net/ (CCNP training) | Cisco Networking Academy | CCDA 200-310
