Starting on Tuesday night, users of Verizon's LTE (long-term evolution) network with any device. The carrier that it had quickly found the cause of the crash and solved it. In between, the carrier's most advanced mobile data network was unavailable.

The nationwide failure was a major embarrassment for Verizon, which markets itself as having a more reliable network than its main rival, AT&T. It was also a reminder that even the most sophisticated systems can fail.

Users of the HTC Thunderbolt, Verizon's only LTE handset, were able to make phone calls or use data services via the carrier's 3G EV-DO (Evolution-Data Optimized) or earlier 1x-RTT networks. Data devices such as the LG VL600 USB modem were supposed to switch over to 3G, but in at least one case, even that network was unavailable.

"If it happens once more I will go back to cable Internet/Wi-Fi usage in my home office, depend on hotel Internet and Wi-Fi hotspots when I'm not either at the office or home office ... and cancel service on the Verizon Wireless network for laptop data usage in favor of these more reliable options," said Verizon subscriber Bruce Ehrle, who normally works at home in Northern Virginia rather than drive to his office in Washington, D.C.

Ehrle previously used Verizon's 3G service but was won over by Verizon's promises of fast LTE performance. The new network was fast, but the LTE modem and software regularly have required restarts. Then, starting around 2 a.m. on Wednesday, Ehrle started to get a "Network not authorized" message when trying to start LTE, and when he tried to switch to 3G, he saw an "Unable to connect" error. He had to commute to his office and work late to have an Internet connection. Only after returning home late Wednesday night was he able to connect to the 3G network, Ehrle said in an e-mail interview.