CNEn case studies
CNEn · Put your knowledge to work in context.
The Certified Network Engineer (CNEn) is a vendor-neutral credential aimed at practitioners who design, build, secure, and operate data networks rather than at candidates seeking a single vendor's specialist track. It suits network engineers, NOC and operations staff, systems administrators who own connectivity, and security generalists who need credible depth in routing, switching, and traffic control. The CNEn case studies are 6 cases and about 4,995 words.
1Layer 2/Layer 3 Boundary for a New Distribution Center
A 480-employee distribution center is moving into a refurbished three-floor building. Each floor will hold 150 desk users, 40 IP phones and 14 Wi-Fi 6 access points; the warehouse adds 200 handheld scanners and 60 IP cameras.
824 words, about 4 min2Dual-Homed BGP with a Provider-Assigned /24
A regional SaaS provider runs 203.0.113.0/24 from AS 65010 and is dual-homed. ISP-A (AS 64500) provides 200/50 Mbps and the address space is provider-aggregatable space allocated by ISP-A.
835 words, about 4 min3802.1X Closed Mode in a Hospital with Non-Supplicant Devices
A 900-bed hospital has 1,400 access ports across 60 wiring closets, all currently in VLAN 1 with no port authentication. The CISO has mandated 802.1X in closed mode on every port within six months.
824 words, about 4 min4DHCP Exhaustion and Split DNS After a Campus Expansion
A university campus serves 8,000 concurrent endpoints across three buildings: about 2,000 wired staff devices, 4,500 student laptops and phones on Wi-Fi, and 1,500 guest devices. DHCP runs on two Windows servers in a 50/50 failover relationship serving a single /20 (10.50.0.0/20) for the student SSID, with an 8-day lease; wired staff use static addresses except for 300 printers.
651 words, about 3 min5ERP Slowdown in the AF31 Queue Every Afternoon
At a 300-person branch, ERP invoice posting has degraded from about 4 seconds to 40–60 seconds every weekday between 13:45 and 15:30. The branch connects to HQ over a 50 Mbps MPLS circuit with four QoS classes: EF 30% for voice, AF31 25% for ERP, AF11 20% for backup, and default 25%.
947 words, about 5 min6SD-WAN Migration with Two Data Centers and Six LTE-Only Sites
A 40-site manufacturer in 22 countries has an MPLS contract that expires in nine months. The current hub-and-spoke design backhauls all internet traffic to Frankfurt, so Teams calls from Asian plants show 180–220 ms RTT and jitter complaints.
914 words, about 5 min