Two-tier vs three-tier campus design and the spine-leaf alternative at the depth ENCOR expects: what each layer does, when to pick each design, and how the pieces connect to QoS and network virtualization.
ENCOR expects you to read an existing QoS policy and say what it does and whether it works. This post gives you a repeatable method for interpreting policy-maps and show output, using the real policy from the PingLabz QoS cluster.
A flat policy cannot say shape everything to 20 Mbps and give voice priority inside that 20. Hierarchical QoS nests one policy in another: a shaping parent and queueing children, built on Cisco IOS XE after the shaping vs policing groundwork.
Tail drop causes global synchronization exactly when the network is busiest. WRED fixes it by dropping packets early, deliberately, and at random. This guide explains why that works and how to configure it.
Build the full LLQ and CBWFQ queueing policy on Cisco IOS XE, then congest a real link to prove the priority class stays protected. Voice goes first, always, and everything else shares what is left fairly.
ENCOR asks you to read Python and JSON, not write it. Learn to parse a script's structure in seconds and read JSON payloads fluently, a comprehension skill worth free marks under exam pressure.
SD-WAN Manager (vManage) exposes a REST API for the entire Catalyst SD-WAN fabric. This article walks the API's shape for network engineers: monitoring the fabric, pulling tunnel health, and automating policy changes.
Catalyst Center exposes everything through a REST API: inventory, intent, and assurance data at scale. This article explains the API model and the categories of endpoint, with documentation-style request and response examples.
A script that ignores HTTP response codes eventually lies about success. This covers the codes that matter for RESTCONF, Catalyst Center, and SD-WAN Manager APIs, what 200, 404, and 500 tell you, and how to act on each.
YANG is the schema language behind NETCONF, RESTCONF, and gNMI. This post explains data models for network engineers: what a model defines, the difference between native and OpenConfig models, and how to actually explore one.
RESTCONF exposes the same YANG models as NETCONF over ordinary HTTPS: GET to read, PATCH to modify, PUT to replace, DELETE to remove. If you can use curl or Python requests, you can drive a Catalyst 8000v with it.
NETCONF replaces screen-scraping with structured XML over SSH against YANG models. This walkthrough drives Cisco IOS XE with ncclient from a real Linux automation host, from first hello to config change.