SAN FRANCISCO, Sept 6 -- Tropic Networks Inc., a developer of optical packet networking systems, has secured $10 million from a venture capital consortium. Andover, Mass.-based Tropic makes components to eliminate metro-area constraints for delivering high bandwidth Internet protocol and Ethernet-based services. With its latest funding -- provided by Silicon Valley Bank, GATX/MM Venture Finance Partnership, and Transamerica Commercial Finance Corp. -- year-old Tropic has raised about $70 million. The latest funding will be used for product development and customer acquisition, Tropic said in a statement.