P3 Reads a Into Cache
•The local directory controller determines if block is locally/remotely allocated
•If remote it finds the home … by high order bits probably
•Controller asks home node for blk: Message to P1
•Home controller looks up directory entry for blk
•Dirty bit OFF, controller finds blk in memory, sends message to P3, sets xth presence bit ON
P1
a:V:4
Controller
a:4
01101
P2
$
Controller
P3
a:V:4
Controller
P0
a:V:4
Controller
Interconnection Network
Msg: P3 to P1, Read a
Msg: P1 to P3, Here’s a