An IP address (abbreviation of Internet Protocol address) is an identifier assigned to each computer and other devices (e.g., printer, router, mobile device, etc.) connected to a TCP/IP network that is used to locate and identify the node in communications with other nodes on the network. In other words, the IP address is an address bound to the network device, i.e., computer, via software.
In a Windows-powered computer, the Windows operating system allows the user to configure the IP address the specific workstation will have. This IP address is used to allow all network aware programs, i.e., Internet Explorer, Netscape, Outlook, etc. to use this address when communicating with other hosts. The seventh layer in the OSI model has the IP addresses. Version 4 of the Internet Protocol (IPv4) defines an IP address as a 32-bit number.
The IP address space is managed globally by the Internet Assigned Numbers Authority (IANA), and by five regional Internet registries (RIR) responsible in their designated territories for assignment to end users and local Internet registries, such as Internet service providers.
IPv4 addresses have been distributed by IANA to the RIRs in blocks of approximately 16.8 million addresses each. Each ISP or private network administrator assigns an IP address to each device connected to its network. Such assignments may be on a static (fixed or permanent) or dynamic basis, depending on its software and practices.
On the other hand, a data-link layer address uniquely identifies each physical network connection of a network device. Data-link addresses sometimes are referred as physical or hardware addresses. Data-link addresses usually exist within a flat address space and have a pre-established and typically fixed relationship to a specific device.
The data link address is a hardware address, which means it is unique to the network card installed on your PC. No two devices on a local network should ever have the same data link address. In the unlikely event this occurs, the two devices will have major communication problems. During the manufacturing process, the vendor “burns” a specific data link address into each network card’s ROM.
When the serial numbers have all been used, they start from the beginning, as it’s very unlikely anyone would buy two network cards from the same vendor, and they will contain the same data link address.
So, to sum all that up, an IP address is a logical address which is configured via the operating system, while the Data link address is a hardware address, burnt into the network card’s ROM during the manufacturing process.