The workloads a network engineer connects have moved. Some are still in a data centre you can walk into; many are in a public cloud you will never see; most enterprises are somewhere in between, running both at once. Designing
A core router or switch reloading should not take the network down. In a well-designed high-availability platform, a supervisor can fail, or software can be upgraded, and traffic keeps flowing with barely a ripple. The technologies that make
Every campus network is some answer to the same question: how do you connect thousands of users to each other and the outside world, reliably, at a cost you can justify, in a way you can grow? The classic answers
The ENCOR blueprint has a specific, easily-underestimated line: "interpret QoS configurations." Not design them, not configure them from scratch, but read an existing policy and a show output and say what it does and whether it is
A single flat QoS policy works fine until reality intrudes: you have a 100 Mbps physical interface but the carrier only sold you 20 Mbps, or one physical link carries traffic for ten branch sites that each need their own
The obvious way to handle a full queue is to drop whatever arrives once the queue is full. It is called tail drop, it is the default, and it causes a subtle, damaging problem that gets worse exactly when the
When a WAN link congests, something has to give, and QoS is how you decide what. Left to itself, a link under load treats a voice packet exactly like a bulk file transfer, and the call breaks while the download
The ENCOR exam does not ask you to be a software developer, but it does ask you to read a Python script and a JSON payload and understand what they do. Under exam pressure, a screen of code you half-
If Catalyst Center is the controller for the campus, SD-WAN Manager (formerly vManage) is the controller for the WAN. It orchestrates the entire Cisco Catalyst SD-WAN fabric, every edge router, every policy, every tunnel, and like every modern
Automating a single router with NETCONF is one thing. Automating a campus of hundreds of devices, with a single source of truth for intent, is what Catalyst Center (formerly DNA Center) is for. It is Cisco's controller for
An automation script that ignores HTTP response codes is a script that will eventually break something quietly. It sends a change, gets back a 409 it never checks, reports success, and moves on, and now your intent and the device&
Every modern network API, NETCONF, RESTCONF, gNMI, is really a way of moving structured data in and out of a device. And structured data needs a schema: an agreed definition of what fields exist, what type each one is, and