CCNA case studies
CCNA · Put your knowledge to work in context.
The Cisco Certified Network Associate (CCNA) is Cisco's associate-level networking certification and the usual entry point into Cisco's certification path. It suits people who want proof of practical, day-to-day networking skill rather than product-specific depth: helpdesk and NOC staff moving into network roles, career changers coming out of a networking course, and junior engineers who already touch routers and switches and want a structured, vendor-recognized credential to show for it. The CCNA case studies are 5 cases and about 4,136 words.
1OSPF Neighbor Flapping Between EXSTART and EXCHANGE
R1 and R2 are directly connected over Gi0/1 in OSPF area 0 on 10.10.12.0/30. Both interfaces are up/up, and ping between 10.10.12.1 and 10.10.12.2 succeeds at every payload size below 1400 bytes.
820 words, about 4 min2Approving a VLSM Plan Inside a /22
You are asked to approve a junior engineer's addressing plan for a new site that was assigned 172.20.16.0/22. Requirements: VLAN 10 needs 400 hosts, VLAN 20 needs 120, VLAN 30 needs 60, VLAN 40 needs 25, plus three point-to-point links to WAN routers, each a /30.
728 words, about 4 min3Root Bridge and Topology Changes on a Three-Switch Campus
Three switches run rapid PVST+. SW1 is the collapsed core: it holds the SVI and default gateway for every VLAN.
871 words, about 4 min4Port Security and DHCP Snooping in a 40-Person Office
SW-A is the only access switch at a 40-person office. Users are in VLAN 30 (10.30.30.0/24); the gateway is R1's Gi0/0.30 across a trunk on SW-A Gi0/1, and the DHCP server is 10.30.10.10, two hops behind R1, reached through an ip helper-address on R1.
841 words, about 4 min5A Nightly Blocklist Job Across 200 Branch Routers
Your team pushes a nightly threat-intel blocklist to 200 IOS-XE branch routers. A Python script using Netmiko loops over the inventory and, for each of about 60 flagged addresses, sends access-list 101 deny ip host <addr any , then disconnects.
876 words, about 4 min