CNPA case studies
CNPA · Put your knowledge to work in context.
The Certified Network Professional Associate (CNPA) is an entry-to-intermediate networking credential aimed at people who have some hands-on exposure to networks and want a structured, vendor-neutral way to prove it. Typical candidates are help-desk technicians moving into network roles, junior administrators, and career changers who have finished a foundational course. The CNPA case studies are 5 cases and about 3,526 words.
1The Redundant Fibre That Took Down VLAN 20
Northgate Manufacturing runs three switches: SW1 at the distribution layer (root bridge, priority 4096) and SW2 and SW3 in the wiring closets. Every inter-switch link is an 802.1Q trunk carrying VLAN 10 (voice), VLAN 20 (office) and VLAN 99 (management).
690 words, about 3 min2Fitting a Hospital's Growth into a Single /22
Meridian Regional Hospital has been assigned one block, 192.168.40.0/22, for a new clinical wing and may not use anything outside it. Facilities requires a separate VLAN for each of the following: Clinical workstations: 380 hosts today, and the CIO insists on 25% headroom inside the same subnet.
630 words, about 3 min3OSPF Neighbour Stuck in EXSTART Across Metro Ethernet
Harborline Logistics has just turned up a 1 Gbps Metro Ethernet circuit between HQ router R1 (GigabitEthernet0/1, 192.0.2.1/30) and the new distribution centre router R2 (192.0.2.2/30). The provider presents the circuit as a transparent Layer 2 segment, so both routers see a broadcast network, and OSPF area 0 is configured on both.
724 words, about 4 min4Six APs, One 2.4 GHz Band, Sixty Users
A 3-floor office with about 90 staff and 60 concurrent devices has six access points, all running 2.4 GHz only - the 5 GHz radios were administratively disabled because 'the laptops are old'. All six APs transmit at maximum power on channels 1, 6 and 11, and channel 6 is used twice: AP-3 and AP-6 sit directly above one another on adjacent floors.
747 words, about 4 min5Passive FTP Behind a Static NAT and a Strict ACL
Cobalt Freight runs an FTP server at 10.10.5.20 in a DMZ, statically NATed to 203.0.113.20 on the internet-facing router R-EDGE. A new partner must pull daily shipment files from it.
735 words, about 4 min