An IT worker with only three months' experience recounted, in The Register's "Who, Me?" column, being sent as the designated "Cisco expert" to install a switch for a customer running Nortel equipment, despite having no real expertise in either system. Confident after completing the rack installation, basic configuration and requested VLANs, he left the client's team to discover shortly afterwards that his new switch had caused over 4,000 AS/400 sessions to drop, forcing the client's IT staff to manually kill and restart each one.

A post-mortem traced the fault to the new switch's spanning-tree settings, which disrupted the SNA-over-TCP/IP emulation linking hosts to the mainframe, a setup with zero tolerance for dropped packets. The author, writing under the pseudonym "Martin," said he was mortified at repaying the client's hospitality with an hour of chaos, but reflected that the real fault lay with his employer for labelling a junior engineer "the expert" and sending him unsupervised to a major client. He kept his job, but said the experience taught him valuable lessons.