Hierarchical Design – (Campus Core , Distribution, Access)

ACCESS

• Redundant supervisors, power supplies, uplink connections, FHRP, Stackwise.
• Dedicated to meeting the functions of end-device connectivity.
• First layer of defense in the network security architecture.
• First point of Negotiation between end devices and network infrastructure.
• Feature rich because of the various devices connected to it.
  • Security, QOS, policy trust boundry functions.

DISTRIBUTION

• Redundant paths, layer3 load sharing, dynamic routing, FHRP.
• Aggregation point for all access nodes.
• Connectivity and policies for traffic-flows within a single access-distribution block (east-west traffic flows).
• Aggregation, policy control, isolation demarcation points between campus distribution blocks. ( north-south traffic flows).
• Configuration choices often depend on the requirements of the access layer.

CORE

• Highest speed and failover.
• Dedicated to providing nonstop connectivity across the entire network.
• Always on mode ( 7x24x365).
• Provides the appropriate level of redundancy.
• he core layer serves as the aggregator for all the other campus.
  blocks and ties together the campus with the rest of the network.
• A sperate core layer isnt needed for a small network <300 users (Collapsed core design).

MODULARITY

• The advantage of the modular blocks due to the isolation it can provide.
  • Failures that occur within a module can be isolated from the rest of the network.
• Modular blocks offers repeatable design standards.
  • When one module is missing capacity it can be updated or replaced by a new block with the same structured role.
• A campus network can have multiple different modules ( Building blocks / places in the network PINs).

FLEXIBILITY

• Control plane flexibility
• Forwarding plane flexibility
• User group flexibility
• Traffic management and control flexibility
• flexibility to support multitenancy and traffic isolation requirements