100-490 RSTECH case studies
100-490 RSTECH · Put your knowledge to work in context.
The 100-490 RSTECH exam, titled Supporting Cisco Routing and Switching Network Devices, is a Cisco exam listed on Cisco's official exams page. It targets IT support staff, field technicians, and partner or reseller engineers who install, configure, maintain, and troubleshoot Cisco routing and switching equipment in customer environments rather than design architectures from scratch. The 100-490 RSTECH case studies are 5 cases and about 4,529 words.
1Root Bridge on an Access Switch: Warehouse Closet Re-Cable
Northfield's HQ has two Catalyst 9300 distribution switches, DS1 and DS2, interconnected and running Rapid PVST+ for 14 VLANs. Twelve access switches have single uplinks: six to DS1, six to DS2.
890 words, about 4 min2Border Router in ROMMON After an Image Swap
An engineer upgraded the border router at a distribution center: an ISR 4331 with a single 8 GB flash and no USB drive on site. A new IOS XE image was copied from an HQ TFTP server, boot system flash bootflash:<new-image .bin was added, show bootvar was checked, the previous image was deleted to free 780 MB, and a reload was scheduled for 02:00.
854 words, about 4 min3SMB, HTTPS, and RDP Stall Across an IPsec Tunnel
Silver Creek's plant connects to HQ through a site-to-site IPsec tunnel on ISR 1111 routers. The tunnel interface MTU works out to 1400 bytes; both LANs are 1500.
924 words, about 5 min4Phones Register but Every PC Behind a Phone Fails DHCP
Riverside branch runs a single Catalyst 9200 (48 ports) with the uplink to the branch router on Gi1/0/1. After a rogue DHCP server incident three months ago, DHCP snooping was enabled on VLAN 10 (data) and VLAN 20 (voice), with Gi1/0/1 configured as trusted.
929 words, about 5 min5Hardcoded Duplex on an ISP Handoff
Calder Freight's primary internet circuit is a 100 Mb/s fiber-to-copper handoff: the carrier's media converter presents an RJ-45 to Gi0/0/0 on an ISR 4331. Last month the link flapped during a carrier maintenance window and the on-call engineer hardcoded speed 100 and duplex full on Gi0/0/0; the flapping stopped.
932 words, about 5 min