At Interop in Vegas, reps from tech services companies were pounding a familiar mantra: Offshore outsourcing is necessary because there aren't enough tech workers in the U.S. to meet demand. Will the Senate listen to them?

At a conference session on sourcing strategies on Wednesday, execs from IBM, Avaya, and CenterBeam spoke about the best ways to plan and implement an outsourcing initiative.

For the most part, it was about important, but dry stuff: A lot of talk about service level agreements, process integration, adherence to standards, and the like.

Then someone asked about outsourcing's impact on jobs.

It is, in the words of panel moderator Johna Till Johnson, of Nemertes Research, a "hot button issue."

Michael Massey, VP and GM of Avaya's Global Managed Services group, said that "reduction of personnel is always a concern" when Avaya takes over a customer's network operations.

But the truth, according the panelists, is that presently in the United States there aren't enough IT workers to go around. Massey said that in many cases Avaya customers call in an outsourcer simply because they aren't able to hire enough tech workers internally.

And Karen Hayward, chief sales and marketing officer at managed services provider CenterBeam, said "the market [for IT labor] is so tight we're filling open positions" when CenterBeam takes over an account.

By contrast, IT worker groups like Alliance@IBM and WashTech argue that the H-1B program, which is presently capped at 65,000 visas annually but could double under proposed legislation, already is too large and is costing American workers their jobs.

With the Senate debating sweeping changes to the nation's immigration laws, expect the voices arguing for, and against, increases in H-1B visas and other pro-immigrant measures to get louder and louder.