Verizon’s LTE outage problems just won’t stop

Updated. Verizon’s(s vz)(s vzw) continuing struggle to keep its LTE network running consistently has landed it in the news again. Wednesday morning, Verizon Wireless reported on its Twitter feed that it is looking into customer complaints about its 4G service going down, and Engadget and Phandroid are reporting network outages in several markets ranging from Phoenix, Ariz., to Indianapolis, Ind.

According to Verizon’s tweet, only the 4G network appears to be affected:

VZW is investigating customer issues in connecting to the 4GLTE data network. 3G data, voice and text services are operating reliably.

Update: At 10:21 PT, Verizon notified customers through its Twitter feed that LTE service had been fully restored. Verizon called the outage a “brief issue,” which may be true, but it certainly wasn’t a localized one. As you can see in the comments to this post, GigaOM readers reported losing 4G connectivity, and sometimes 3G, from all over the country.

Depending on the scope and duration of the problem, this outage could pass by with little notice, or it could be another black eye for Big Red, which suffered a chain of big LTE failures in December. Those problems were all caused by bugs in Verizon’s core service delivery architecture – in telco speak called the IP Multimedia Subsystem, or IMS – but Verizon VP of network engineering Mike Haberman said the carrier had since taken multiple steps to ensure that such problems wouldn’t occur again. From our December post:

While Verizon won’t promise that no more outages will occur, Haberman said it has taken measures to ensure that they’re minimized when they do happen in the future. He said he’s begun geographically segmenting the LTE network, so if a software bug does break out it can be isolated to a particular region or market instead of spreading nationwide. Verizon is also upgrading all of its software and cutting down on the signaling clutter running over its IMS grid.

“Our goal is to ensure that our 4G network meets the same high standard that our 3G network does,” Haberman said. “We’re not there yet, but we’ll get there.”

In the current outage, 3G service appears to be working for LTE smartphone customers as it did in previous outages. Thus, Verizon may  be experiencing problems with its IMS core once again.