Sharecast - Spirent said on Wednesday that the deal was worth $15.0m, of which $12.0m has already been received, with the remainder for additional implementation services due in the new year.
The FTSE 250-listed firm also noted that it had recently acquired the test lab automation business of NetScout Systems, a small carve-out based in New Jersey, for "a modest sum".
Spirent (LON:SPT) said the acquisition of this business brought "important intellectual property" that will enable it to add physical layer switching capability to its existing lab automation software platform. It added that the financial impact of this small technology business was "not material".
Chief executive Eric Updyke said: "We are delighted to confirm receipt of this important strategic order that provides a proof point of our drive to leverage our world-leading test and automation solutions into a new set of customers, with complex network environments they are struggling to test and validate manually.
"Further, we have responded to this market opportunity by acquiring important technology to accelerate our drive into the lab automation space with comprehensive solutions which we believe align well with our telco and enterprise customers' current focus on efficiency and cost savings."
As of 0840 GMT, Spirent shares were up 1.38% at 110.30p.
Reporting by Iain Gilbert at Sharecast.com