IP地址同MAC地址既分別

IP ADDRESS:

An Internet Protocol (IP) address is a numerical identification (logical address) that is assigned to devices participating in a computer network utilizing the Internet Protocol for communication between its nodes.[1] Although IP addresses are stored as binary numbers, they are often displayed in more human-readable notations, such as 192.168.100.1 (for IPv4), and 2001:db8:0:1234:0:567:1:1 (for IPv6). The role of the IP address has been characterized as follows: "A name indicates what we seek. An address indicates where it is. A route indicates how to get there." [2]
Originally, an IP address was defined as a 32-bit number[1] and this system, now named Internet Protocol Version 4 (IPv4), is still in use today.

More information: http://en.wikipedia.org/wiki/Ip_address

MAC ADDRESS:

In computer networking a Media Access Control address (MAC address) or Ethernet Hardware Address (EHA), hardware address, adapter address or physical address is a quasi-unique identifier attached to most network adapters (NIC or Network Interface Card). It is a number that serves as an identifier for a particular network adapter. Thus network cards (or built-in network adapters) in two different computers will have different MAC addresses, as would an Ethernet adapter and a wireless adapter in the same computer, and as would multiple network cards in a router. However, it is possible to change the MAC address on most of today's hardware, often referred to as MAC spoofing. layer 2 network protocols use one of three numbering spaces managed by the Institute of Electrical and Electronics Engineers (IEEE): MAC-48, EUI-48, and EUI-64, which are designed to be globally unique. Not all communications protocols use MAC addresses, and not all protocols require globally unique identifiers. The IEEE claims trademarks on the names "EUI-48" and "EUI-64" ("EUI" stands for Extended Unique Identifier).

More information: http://en.wikipedia.org/wiki/Mac_address

(1). MAC addresses are 12-digit hexadecimal numbers, IPv4 addresses consist of four bytes (32 bits). Each byte of an IP address is known as an octet. In IPv6, IP addresses change from the current 32-bit standard and dotted decimal notation to a new 128-bit address system.

(2). MAC address represents the serial number assigned to the adapter by the manufacturer. IP addresses can be determined statically (assigned to a computer by a system administrator) or dynamically (assigned by another device on the network on demand).

(3). A MAC address represents the physical identifier of a network adapter, the IP address represents a logical device address on Internet Protocol networks.

(4). Computers can determine IP addresses from MAC addresses using DHCP and other protocols like RARP and InARP, but there is no mechanism for us to determine an IP address given a known MAC address, although it can be done in certain specific situations.

2008-07-30 12:19:56 補充：
(5). MAC address for frame delivery which is direct connected transmission used in Layer 2 data link layer, IP address for packet delivery which is routed transmission used in Layer3 Network layer.