Leaf switch

As explained in Acing the CCNA Exam: Volume 2 Advanced Networking and Security

A leaf switch is a switch in the endpoint-facing layer of a spine-leaf data-center topology that connects to hosts and spine switches.

A leaf switch forms the endpoint-facing layer of a spine-leaf data-center topology. Servers connect to leaf switches, and each leaf connects to every spine switch. section 15.3.2

Key operational characteristics include:

• Avoids leaf-to-leaf connections; traffic between different leaf switches traverses one spine switch. section 15.3.2
• Provides consistent, predictable server-to-server latency because leaf switches are equally distant from one another. section 15.3.2
• Scales by adding a leaf switch and connecting it to every spine switch. section 15.3.2
• Uses the term border leaf for a leaf switch connected to the WAN, internet, or another external network. section 15.3.2

Figure 15.9 Spine-leaf architecture, a two-tier LAN architecture commonly used in modern data center networks

Use the topology figure to trace host-to-host paths through leaf and spine layers. section 15.3.2

How Acing the CCNA Exam: Volume 2 Advanced Networking and Security covers it

How deep it goes

Explains placement, interconnection rules, latency behavior, border-leaf terminology, and scaling, without configuration procedures.

Examples

Uses host-to-host paths, same-leaf exceptions, border-leaf links, and adding leaves across all spine switches.

What you can do after

Evaluate leaf-switch placement, expected hop counts, latency consistency, and straightforward fabric expansion.

How it connects

Ties leaf switches to spine switches, spine-leaf architecture, border leaves, servers, and east-west traffic.

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Related concepts

• spine-leaf architecturepart of · Spine-leaf architecture is a two-layer data-center network design in which leaf switches connect to end hosts and every leaf connects to every spine switch.
• spine switchcontrasts with · A spine switch is a switch in the upper layer of a spine-leaf data-center topology that connects to leaf switches.

This explainer was generated by Manning's knowledge graph from the text of Acing the CCNA Exam: Volume 2 Advanced Networking and Security. The section links point to the parts of the book it draws on.