HLD (High-Level Design) and LLD (Low-Level Design), are two important terms in mobile networks design. They are essential for ensuring the successful design, implementation, and deployment of mobile networks

The HLD is the initial stage of the network design process. It focuses on the overall system architecture, defining the major components, their interactions, and the high-level functionality of the network.

It includes many information such as, network topology, core network elements, network interfaces and protocols.

While the LLD is the more detailed, technical stage of the network design process. It translates the high-level architectural decisions into a concrete, implementable plan for the network.

It typically includes information such as detailed hardware and software specifications, network element configurations and settings, deployment and integration procedures.