Why IP Address is necessary for each computer!

it is not necessary because you can make it daynamic and it will works too but if u would like to share data from ur pc to ur lan so u have to had ip address

IP addresses are an integral part of any corporate network, and companies large and small are consuming them faster with more applications and devices than ever before. Overlooking the importance of getting a handle on IP addresses can prove disastrous. IP addresses are one of the most critical resources that need to be managed in any network. Every networked application and device -- from e-mail and Web connectivity to file storage and networked printers -- depends on IP and requires address assignment. That presents a big enough challenge, but it's becoming an even bigger challenge as new core services like VoIP and mobile networks increase IP address assignment needs, requiring more robust allocation, classification, and tracking of addresses.

Each node in a network is identified by its ip address.. it is needed to transfer data between connecting devices..