Carrier cloud

This may result in unpredictable response times and security issues when business-critical data are transferred over the Internet.

The advent of virtualization technology, cost-effective computing hardware, and ubiquitous Internet connectivity have enabled the first wave of cloud services starting in the early years of the 21st century.

[1][2][3][4] But many businesses and other organizations hesitated to move to more demanding applications, from on-premises dedicated hardware to private or public clouds.

[5] Cited weaknesses vary but often include possible downtime, security issues,[6][7][8][9] high cost of custom software and data transfer, inflexibility of some cloud apps, poor customer and nonfulfillment of service level agreements (SLAs).

Links between data centers are used for failover, overflow, backup, and geographic diversity.