Various models and protocols have been devised for maintaining coherence, such as MSI, MESI (aka Illinois), MOSI, MOESI, MERSI, MESIF, write-once, and Synapse, Berkeley, Firefly and Dragon protocol.
MSI، MESI، MOSI، MOESI، MERSI، MESIF، write-once، Synapse، Berkeley، Firefly، Dragon protocol