Internet networking pioneer Cisco Systems is jettisoning more than 4,000 employees, joining the parade of technology companies in a trend that has helped boost their profits and stock prices while providing a sobering reminder of the job insecurity hanging over an industry increasingly embracing artificial intelligence. The mass layoffs announced Wednesday in conjunction with Cisco’s latest quarterly results represent about 5% of its worldwide workforce of 84,900. The purge follows Cisco’s late 2022 cutbacks that shed 5,000 workers and ahead of its $28 billion acquisition of Splunk, a deal that management now expects to complete by April 30.