Operational Monitoring and Maintenance

JN0-106 · 23 questions

• A technician at a rural fiber cooperative's head-end needs a fast overview of every interface's administrative and link status on an aggregation router before a scheduled maintenance window. Which command gives that summary in one screen without digging into per-interface detail?
• While reviewing show interfaces ge-0/0/2 extensive on a subscriber-aggregation switch feeding a small-town fiber node, a technician sees the Input errors counter climbing with framing errors accounting for most of the count. What does this most likely indicate?
• A cooperative's core router shows a steadily increasing Output drops counter on the interface uplinked to a subscriber-aggregation switch, while Output errors stays at zero. What does that pattern point to?
• A NOC engineer at a rural telecom cooperative notices the Carrier transitions counter on a POP's uplink interface has climbed into the hundreds over the past hour, while the link currently shows up. What does that counter tell the engineer?
• A technician runs show interfaces terse on a subscriber-aggregation switch and finds a port listed as down, even though a colleague swears the fiber patch and optic on that port were both replaced and tested earlier that day. What should the technician check first before assuming a new physical fault has appeared?
• A technician troubleshooting a slow subscriber link wants to watch live, continuously-updating traffic statistics (bits per second, packets per second) for one interface directly from the Junos CLI, without generating a static, one-time report. Which operational-mode command provides that live view?
• An engineer at a rural ISP's carrier-hotel POP needs to inspect the actual packet headers crossing an interface in real time, similar to a lightweight packet sniffer, to confirm a subscriber's DHCP requests are actually reaching the router. Which Junos CLI command is built for that?
• A field technician needs to quickly confirm basic IP reachability to a subscriber's CPE at a remote village site without waiting a full second between each probe. Which Junos ping option is built for that fast check?
• A subscriber several hops downstream from a cooperative's core reports intermittent connectivity to the internet. Running traceroute from the core router toward the subscriber's CPE shows normal replies through the fourth hop, then asterisks for every hop after that. What does this output tell the engineer?
• A cooperative's network team is deciding how field techs should remotely access routers at unmanned rural POPs for day-to-day monitoring. Why should SSH be chosen over Telnet for this access?
• After a brief outage at a POP overnight, an engineer wants to review the general system log for events like interface flaps or process restarts that occurred around the time of the outage. Which command displays that log?
• A NOC engineer wants to watch a specific log file update in real time on the terminal, similar to tailing a log on a Linux server, while reproducing an intermittent issue at a POP. Which Junos operational-mode command does that?
• A router at a cooperative's regional hub seems sluggish to respond to CLI input, and the engineer suspects the routing engine's CPU is overloaded. Which command lets the engineer see which processes are consuming the most CPU, similar to a Unix top view?
• Before ordering a replacement part for a router at a remote POP, an engineer needs to confirm the exact model, serial number, and installed FPCs/PICs currently in the chassis. Which command provides that hardware inventory?
• Before pushing a Junos OS upgrade to a router at a rural head-end, an engineer wants to confirm there's enough free space on the device's local storage to hold the new software image. Which command checks that?
• A router at a small-town POP is nearly out of local storage, mostly from old log files and unused software images accumulated over years of operation. Which command helps an engineer identify and optionally remove those unneeded files to reclaim space?
• Before starting a scheduled Junos OS upgrade on a POP router, an engineer wants to confirm the exact software version currently running so the correct upgrade path can be chosen. Which command shows that?
• Before installing a new Junos OS package on a production router at a rural cooperative's core, an engineer wants to check that the package is compatible with the router's current configuration and hardware without actually installing it yet. Which command performs that check?
• An engineer has already validated a new Junos OS package against a POP router's configuration and is ready to actually install it and have the router come up on the new version after a single maintenance-window reboot. Which command accomplishes both the install and the reboot in one step?
• Before upgrading Junos OS on a POP router that has no on-site spare, a cautious engineer wants a bootable backup copy of the current, known-working software and configuration on backup storage media, so the router can be recovered quickly if the upgrade goes wrong. Which command creates that backup?
• A cooperative is scheduling generator maintenance at an unmanned POP that will briefly cut power to a router. To avoid filesystem corruption, an engineer wants to gracefully halt the Junos OS before power is physically removed. Which command should be run first?
• A technician inherits a router at a decommissioned rural POP with an unknown root password and no other configured administrative accounts. What is the general Junos procedure for regaining administrative access?
• A newly hired field tech at a small cooperative office is more comfortable with a graphical interface than the CLI, but still needs a quick read on interface status, system health, and recent log entries for a POP router. What does J-Web's Monitor section provide?