The "time exceeded in-transit" ICMP message is generated when a packet's Time-To-Live (TTL) field reaches zero before reaching its destination. This usually occurs when the packet has traversed too many routers (hops), indicating that the destination is too far away or there is a routing loop causing excessive hops. * TTL Field: Every IP packet has a TTL field which decrements by 1 every time it passes through a router. When TTL reaches zero, the packet is discarded and an ICMP "time exceeded" message is sent back to the sender. * Network Latency: High latency or excessive hops can cause packets to expire in transit, leading to this ICMP message. Reference: Cisco DevNet Associate Certification Guide, Chapter on Network Fundamentals and ICMP.