determine ip and mac frame header information for a data packet

#Determine ip and mac frame header information for a data packet zip

The Inter-Frame Gap or IFG is the period of 9.6 microseconds (at 10 Mbps) that a transmitter must wait between sending frames, to allow for signal propagation at the receiver end. Any frame returning an invalid CRC is rejected by the MAC frame, without processing. Sometimes referred to as a as a Frame Check Sequence, the Cyclic Redundancy Check or CRC is a 32-bit checksum calculated to provide error detection in the case of Ethernet transmission collisions or line errors which could corrupt the MAC frame. A two-byte type field, providing a Service Access Point (SAP) which identifies the type of protocol being carried.A six-byte source address, set to the sender’s unique node address.A six-byte destination address, specifying a single recipient node (unicast mode), several nodes (multicast), or the set of all recipient nodes (broadcast mode).Once this is received, the Ethernet receive interface begins gathering the bits into bytes for processing by the MAC layer. A special pattern (binary 11) is used to mark the last two bits of the preamble.

The Preambleīefore data transmission, there’s a short idle time of 9.6 microseconds (µS) to allow for the receiver circuitry in each node to settle after completion of the previous transmission frame. MAC encapsulates payload data by adding Protocol Control Information (PCI) as a 14-byte header before the information, and adding a checksum for integrity checking. Media Access Control has its roots in network computing under the Ethernet protocol, where it provides the data link layer for LAN systems. MAC assumes responsibility for transmitting data packets to and from a network interface card, or to and from other remotely shared channels. Media Access Control is itself a sub-layer of the Data Link Layer (DLL) defined within the seven-layer OSI ( Open Systems Interconnection) network reference model. Each type of physical device has a different MAC sub-layer. In telecommunication protocols, MAC addresses are used by the Media Access Control sub-layer of the Data Link Control (DLC) layer, which is the protocol layer of a program that handles the flow of data moving in and out over physical links in the network. Some wireless home automation networks defined by IEEE 802.15.4 require hardware devices to be configured with MAC addresses of 64 bits, rather than 48. But as different vendors are issued with different MAC prefixes, it’s possible for devices originating from different manufactures to use the same sequence of “S” digits in their MAC address, without confusing the system. Each piece of hardware manufactured by a given vendor (and operating under a given MAC prefix) has its own unique 24-bit number. The “S” digits on the right give the identification number associated with a specific device. These may be assigned to the various products making up their range of hardware. The IEEE standards authority issues a given set of MAC prefixes to each vendor that registers with it. The string of “M”s on the left (six digits, or 24 bits) is called a prefix, and is associated with the device manufacturer. A traditional MAC address is a twelve-digit hexadecimal number, 48 bits or six bytes long, written in one of the following manners: MAC addresses are sometimes known as physical addresses or hardware addresses, and are set by hardware manufacturers to uniquely identify their devices. The MAC protocol provides a channel of access and an addressing mechanism, so that each available node on the network may communicate with other nodes which are available – either on the same network, or on others. In a LAN (Local Area Network) or other type of network such as the internet, a Media Access Control or MAC address serves as a unique identifier for each piece of hardware. The same holds true for network and internet communications, where part of the hierarchy of identifying traits is provided by MAC, or Media Access Control.

#Determine ip and mac frame header information for a data packet zip

Telecommunications and old-school postal systems use a hierarchy of identifying characteristics (number, exchange, zip or area code, state or country code, etc.) to break the process of transmitting messages into manageable steps, each of which may be handled by mechanisms appropriate to a given stage (mailbox, local sorting office, etc.).