A capacity upgrade to GCI’s cable and internet left about half its Juneau customers without service Thursday, but if you were not awake for it, you may not have known.

Rolling outages affected customers in Lemon Creek, downtown Juneau and parts of Douglas from 12 a.m. to 7 a.m. Thursday morning. Individual customer outages lasted for about two hours each, GCI spokesman David Morris said.

GCI customers working online or enjoying television reruns Thursday morning would have been surprised when they lost service suddenly as GCI did not warn in advance of the outage. Morris said GCI does not usually warn its customers of work during this window. However, that may change.

“We can learn from this and be more proactive in announcing these things,” Morris said.

The outage was during GCI’s scheduled maintenance window. The window is set for a time of low customer use, usually late at night, Morris said.

“We try to avoid making changes during the day when most people are using GCI’s services,” Morris said.

Network companies use these windows to upgrade systems, Morris said.

“You have to have a maintenance window in a network,” he said. “All providers have one.”

The upshot of GCI’s upgrade to its system is a 67 percent increase in capacity for the system.

“It was getting congested,” Morris said. “You do the upgrade before customers start to notice.”

Customers with low bit-rate plans will not see increased performance, but high bit-rate customers may.

So online gamers whose digital dragon battle may have frozen during the outage had plenty of bandwidth to resume the raid later that day.

Customers can expect more upgrades in the future, Morris said.

“There is such a growth in data services that we will always have to keep upgrading capacity,” he said. “That is the trend.”

• Contact reporter Russell Stigall at 523-2276 or at russell.stigall@juneauempire.com.