Question

Difficulty: HardNetwork Topology Architectures

Match each network topology architecture model or functional layer on the left to its corresponding design trait and operational responsibility on the right.

  • Collapsed Core Architecture LayerCombines core transport and policy enforcement into a single redundant switch pair to reduce cost and complexity in small-to-medium enterprise sites.
  • Three-Tier Core LayerProvides high-speed, uncompromised L2/L3 transport without performing CPU-intensive packet inspection, ACL filtering, or policy enforcement.
  • Three-Tier Distribution LayerAggregates Access switches, acts as the Layer 2/Layer 3 boundary, and enforces security policies, QoS markings, and inter-VLAN routing.
  • Data Center Spine Layer (Clos)Functions as a high-bandwidth IP fabric backbone where every leaf switch connects to every switch in this tier with predictable single-hop latency.

Answer

Collapsed Core Architecture Layer matches the description combining core transport and policy enforcement into a single switch pair. Three-Tier Core Layer matches the description providing high-speed transport without CPU-intensive packet inspection or ACL filtering. Three-Tier Distribution Layer matches the description aggregating Access switches, acting as the L2/L3 boundary, and enforcing security policies. Data Center Spine Layer matches the description functioning as a high-bandwidth IP fabric backbone with predictable single-hop latency.
Each architecture layer is uniquely optimized for its operational domain: Collapsed Core combines distribution and core functions for smaller networks; Three-Tier Core optimizes raw forwarding speed without packet filtering; Three-Tier Distribution acts as the control boundary for VLANs, security policies, and routing aggregation; Spine-Leaf Spine nodes provide predictable, non-blocking single-hop transport between all leaf switches.

Step-by-Step Solution

1
Analyze the functional responsibilities of campus network layers.
Identify that the Core layer focuses exclusively on transport speed, while the Distribution layer handles routing boundaries, ACLs, and policy enforcement.
Separation of duties in campus designs prevents performance bottlenecks on the core backbone.
2
Evaluate the Collapsed Core model.
Recognize that Collapsed Core integrates core switching and distribution policies into one physical tier, suited for medium enterprise designs.
Combining layers lowers equipment cost while retaining high availability.
3
Examine data center Spine-Leaf (Clos) architectural dynamics.
Distinguish that Spine switches form a full mesh fabric with Leaf switches to optimize east-west server traffic with deterministic latency.
Spine switches do not connect to each other; they strictly interconnect leaf nodes across a non-blocking Layer 3 fabric.

Key Concept

Network Architectural Layer Functional Responsibilities and Design Trade-offs
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