Packet segmentation
Encyclopedia
In a data communications networks, packet segmentation is the process of dividing a data packet into smaller units for transmission over the network. Segmentation may be required in many scenarios:
Protocols that perform packet segmentation at the source usually include a mechanism at the destination to reverse the process and reassemble the original packet from individual segments. This process may include automatic repeat-request (ARQ) mechanisms to detect missing segments and to request the source to re-transmit specific segments.
In a communication system based on a layered OSI model
, packet segmentation may be responsible for splitting one MPDU
into multiple physical layer
service data unit
s so that reliable transmission (and potential re-transmission via ARQ) of each one can be performed individually.
The ITU-T
G.hn
standard, which provides a way to create a high-speed (up to 1 Gigabit/s) local area network
using existing home wiring (power lines
, phone lines and coaxial cables
), is an example of a protocol that employs packet segmentation to increase reliability over noisy media.
- When the data packet is larger than the maximum size supported by the network.
- When the network is unreliable and it's desirable to divide the information into smaller segments to maximize the probability that each one of them can be delivered correctly to the destination.
Protocols that perform packet segmentation at the source usually include a mechanism at the destination to reverse the process and reassemble the original packet from individual segments. This process may include automatic repeat-request (ARQ) mechanisms to detect missing segments and to request the source to re-transmit specific segments.
In a communication system based on a layered OSI model
OSI model
The Open Systems Interconnection model is a product of the Open Systems Interconnection effort at the International Organization for Standardization. It is a prescription of characterizing and standardizing the functions of a communications system in terms of abstraction layers. Similar...
, packet segmentation may be responsible for splitting one MPDU
MPDU
MAC protocol data unit or MPDU is a message exchanged between MAC entities in a communication system based on the layered OSI model....
into multiple physical layer
Physical layer
The physical layer or layer 1 is the first and lowest layer in the seven-layer OSI model of computer networking. The implementation of this layer is often termed PHY....
service data unit
Service Data Unit
In Open Systems Interconnection terminology, a service data unit is a unit of data that has been passed down from an OSI layer to a lower layer and that has not yet been encapsulated into a protocol data unit by the lower layer...
s so that reliable transmission (and potential re-transmission via ARQ) of each one can be performed individually.
The ITU-T
ITU-T
The ITU Telecommunication Standardization Sector is one of the three sectors of the International Telecommunication Union ; it coordinates standards for telecommunications....
G.hn
G.hn
G.hn is the common name for a home network technology family of standards developed under the International Telecommunication Union's Standardization arm and promoted by the HomeGrid Forum...
standard, which provides a way to create a high-speed (up to 1 Gigabit/s) local area network
Local area network
A local area network is a computer network that interconnects computers in a limited area such as a home, school, computer laboratory, or office building...
using existing home wiring (power lines
Power line communication
Power line communication or power line carrier , also known as power line digital subscriber line , mains communication, power line telecom , power line networking , or broadband over power lines are systems for carrying data on a conductor also used for electric power transmission.A wide range...
, phone lines and coaxial cables
Ethernet over coax
Ethernet over Coax is a family of technologies that supports the transmission of Ethernet frames over coaxial cable.- History :The first Ethernet standard, known as 10BASE5 in the family of IEEE 802.3, specified baseband operation over coaxial cable...
), is an example of a protocol that employs packet segmentation to increase reliability over noisy media.
See also
- Packet aggregationPacket aggregationIn a packet-based communications network, packet aggregation is the process of joining multiple packets together into a single transmission unit, in order to reduce the overhead associated with each transmission....
- Segmentation and ReassemblySegmentation and ReassemblySegmentation and Reassembly refers to the process used to fragment and reassemble variable length packets into fixed length cells so as to allow them to be transported across Asynchronous Transfer Mode networks or other cell based infrastructures. Since ATM's payload is only 48 bytes, nearly every...
- Fujitsu Ltd. v. Netgear Inc.Fujitsu Ltd. v. Netgear Inc.Fujitsu v. Netgear, Inc was a patent infringement case centered around three patents claimed to be required for full compliance of the IEEE 802.11 standard and the WiFi Alliance Wireless Multi-Media Specification. US patents 4.974,952, 6,018,642, and 6,469,993 were owned by Philips...