Juniper Networks (JNPR) - Get Report made a pair of acquisitions Tuesday, adding to its office networking technology as it aims increasingly at big business customers.

The cash-and-stock deal for

Peribit Networks

, a closely held Santa Clara, Calif., computer networking shop, totals $337 million. The cash-and-stock-option value of the acquisition of

Redline Networks

totals about $132 million.

Juniper shares fell 32 cents to $21.99 in postclose trading Tuesday.

One hedge fund manager, who is short Juniper, applauded the move in to the so-called enterprise market, where

Cisco Systems

(CSCO) - Get Report

has been dominant. But he says Juniper paid a hefty price for two relatively unproven ventures.

The combined revenue of the two companies was about $40 million last year, and Juniper has agreed to shell out $469 million for them -- nearly 12 times sales.

"That's a lot of dough for a startup," says the money manager.

But Juniper has been in the hunt for new technologies that can complement the company's core Internet router business. These routers are used by phone companies to help handle a blizzard of Internet communications.

Peribit makes optimization gear that helps better manage and prioritize traffic over computer networks. Closely held Campbell, Calif.-based Redline makes network appliances to help business data centers with Web applications.

"Juniper Networks is capitalizing on its leadership position to redefine the networking market," CEO Scott Kriens said in a press release.