'''Interleaved polling with adaptive cycle time''' (IPACT) is an [[algorithm]] designed by Glen Kramer, Biswanath Mukherjee and Gerry Pesavento of the Advanced Technology Lab at the [[University of California, Davis]] in 2002.<ref>{{Cite book |last=Ma |first=Lin |url=https://books.google.com/books?id=WynRyQgFHh0C |title=Current Research Progress of Optical Networks |date=2009-04-16 |publisher=Springer Science & Business Media |isbn=978-1-4020-9889-5 |pages=128 |language=en}}</ref> IPACT is a [[dynamic bandwidth allocation]] algorithm for use in [[Ethernet]] [[passive optical network]]s (EPONs).
'''Interleaved Polling with Adaptive Cycle Time''' (IPACT) is an [[algorithm]] designed by Glen Kramer, Biswanath Mukherjee and Gerry Pesavento
Advanced Technology Lab.at the [[University of California, Davis]]. IPACT is a dynamic [[bandwidth allocation]] algorithm for use in [[Ethernet]] [[passive optical network]]s (EPONs).
IPACT uses the Gate and Report messages provided by the EPON Multi-Point Control Protocol (MPCP) to allocate [[Bandwidth (signal processing)|bandwidth]] to Optical Network Units (ONUs).<ref>{{Cite Ifjournal the|last1=De [[FiberAndrade to|first1=Marilet |last2=Chen |first2=Jiajia |last3=Skubic |first3=Björn |last4=Ahmed |first4=Jawwad |last5=Wosinska |first5=Lena |date=2013-10-01 |title=Enhanced IPACT: solving the xover-granting problem in long-reach EPON |Opticalurl=https://doi.org/10.1007/s11235-013-9722-1 |journal=Telecommunication Systems |language=en |volume=54 |issue=2 |pages=137–146 |doi=10.1007/s11235-013-9722-1 |s2cid=255099225 |issn=1572-9451|url-access=subscription }}</ref> If the [[optical Lineline Terminalterminal]] 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 (computer science)|downstream]] grant messages to succeeding ONUs while receiving [[transmission (telecommunications)|transmission]]s from previously granted ONUs. It accomplishes this by calculating the time at which a transmission grant allocated to a previous ONU ends.
