云服务对传统外包模式提供的服务模式明显地具有替代作用。根据Gartner最新IT外包业务预测,全球IT服务支出,今年将比2011年增长2.1%,超过2510亿美元。经过调整因汇率引起的变化,今年IT支出实际增长4.1%,与去年增长率持平。外包业务增长最快的板块——云计算服务,预期将从2011年的34亿美元增长到50亿美元,几乎增长一倍。其中“基础设施即服务”(laaS)在 Cloud service obviously has a substitute for the service model provided by the traditional outsourcing model. According to Gartner’s latest IT outsourcing business forecast, global IT service spending this year will grow 2.1% over 2011, more than 251 billion US dollars. After adjusting for the changes caused by the exchange rate, IT spending actually increased by 4.1% this year, unchanged from last year’s growth rate. The fastest-growing segment of outsourced business, cloud computing services, is expected to nearly double from $ 3.4 billion in 2011 to $ 5 billion. Where “infrastructure as a service” (laaS) is