Cost is the biggest concern for companies when considering whether to outsource their wide area network.
A survey conducted by ICM Research on behalf of Vanco, the virtual network operator (VNO), found that three-quarters (74%) of companies already outsource part or all of their Wan.
This outsourcing level increased from the 71% recorded last year, said ICM.
ICM said 76% of companies said low costs over the lifetime of the contract were the major factor in making their next outsourcing decision.
Last year, just 48% of companies said cost was a major factor in their outsourcing decision.
Among the companies that outsource, the biggest problem that they face is difficulty in quickly pinpointing network problems when they occur.
The survey showed that 60% of companies cited this problem, up from 46% in 2005.
Other problems cited included network restoration in the event of a problem (56%), and ongoing billing problems (46%).
Just 19% of companies said security was a major factor in outsourcing decisions.
The survey was carried out among 300 companies. A VNO is a networks and telecoms provider that builds a customer network using different services from a variety of third party providers.