Elements of distributed computing vijay garg

$7\mathrm{.}6.($due to $[$SK$92])$ Suppose that the underlying communication system guarantees FIFO ordering of$$messages$.$ How will you exploit this feature to reduce the communication complexity of the vector$$clock algorithm? Your algorithm should not use more than O$($N$)$ space at any process. $($Hint: Keep$$track of the logical time when any component in the vector clock changed last.$)$