Interleaved polling with adaptive cycle time (IPACT) is an
algorithm
In mathematics and computer science, an algorithm () is a finite sequence of rigorous instructions, typically used to solve a class of specific Computational problem, problems or to perform a computation. Algorithms are used as specificat ...
designed by Glen Kramer, Biswanath Mukherjee and Gerry Pesavento of the Advanced Technology Lab at the
University of California, Davis
The University of California, Davis (UC Davis, UCD, or Davis) is a public land-grant research university near Davis, California. Named a Public Ivy, it is the northernmost of the ten campuses of the University of California system. The institut ...
in 2002. IPACT is a
dynamic bandwidth allocation algorithm for use in
Ethernet
Ethernet () is a family of wired computer networking technologies commonly used in local area networks (LAN), metropolitan area networks (MAN) and wide area networks (WAN). It was commercially introduced in 1980 and first standardized in 198 ...
passive optical networks (EPONs).
IPACT uses the Gate and Report messages provided by the EPON Multi-Point Control Protocol (MPCP) to allocate
bandwidth to Optical Network Units (ONUs).
If the
optical line terminal {{unreferenced, date=April 2016
An optical line termination (OLT), also called an optical line terminal, is a device which serves as the service provider endpoint of a passive optical network. It provides two main functions:
# to perform conversio ...
grants bandwidth to an ONU and waits until it has received that particular ONU's transmission before granting bandwidth to another ONU, then time equivalent to a whole messaging round-trip is wasted during which the upstream may remain idle. IPACT eliminates this idle time by sending
downstream grant messages to succeeding ONUs while receiving
transmission
Transmission may refer to:
Medicine, science and technology
* Power transmission
** Electric power transmission
** Propulsion transmission, technology allowing controlled application of power
*** Automatic transmission
*** Manual transmission
*** ...
s from previously granted ONUs. It accomplishes this by calculating the time at which a transmission grant allocated to a previous ONU ends.
References
External links
*
Original paper, published January 2002
Network scheduling algorithms
{{compu-network-stub