During a routine maintenance window, a network administrator attempts to apply a firmware update to a core distribution switch at an unmanned remote facility. The update fails, corrupting the flash memory and placing the switch into a continuous boot loop, which brings down all VLAN interfaces and primary IP routing. The administrator needs to gain low-level CLI access to the switch's bootloader to restore the operating system image and must also be able to perform a hard power-cycle if the device hangs. Which out-of-band management configuration best fulfills these requirements?
- Connect the switch's RS-232 serial console port to an out-of-band terminal server paired with an independent cellular modem, and plug the switch's power cord into a remotely managed switched PDU.Answer
- BEstablish an SSH session over TCP port 22 directly to the switch's out-of-band management IP address and execute an SNMPv3 power-cycle command.
- CConfigure a Virtual Network Computing (VNC) session over UDP port 23 targeting the switch's loopback interface to access the graphical boot menu.
- DDeploy an IP-KVM gateway connected to the switch's primary Ethernet uplink and utilize unencrypted SNMPv2c traps to issue hard power reset signals.
Answer
Connecting the switch's serial console port to an out-of-band terminal server with a cellular modem and utilizing a remotely managed switched PDU is the optimal solution.
When a network switch suffers flash corruption and enters a continuous boot loop, all Layer 2 and Layer 3 in-band network interfaces become unreachable. Establishing out-of-band (OOB) management via a terminal server connected to the switch's serial console port provides direct CLI access to the ROMMON bootloader over an independent cellular path. Additionally, plugging the switch into a remotely managed switched PDU enables administrators to hard power-cycle the switch remotely without requiring on-site technical personnel.
Step-by-Step Solution
Key Concept
Out-of-Band (OOB) Management and Remote Infrastructure Access