What is iou and isu in tcs?

TCS delivery mechanism is through its Independent Operating Units (IOUs) that conceptualize, sell, deliver and support TCS' offerings to create value for customers. A2A TCS' Horizontal Service Delivery Units provide their services to all industries and markets in collaboration with the ISUs. there are lots of people who hv limited ideas about ISU. It is almost impossible for you to get release from that projects,so better leaving TCS itself instead off begging them for release.