End-to-end delay

End-to-end delay refers to the time taken for a packet to be transmitted across a network from source to destination.

d_end-end= N[ d_trans+d_prop+d_proc]

where
d_end-end= end-to-end delay
d_trans= transmission delay
d_prop= propagation delay
d_proc= processing delay
N= number of links (Number of routers + 1)
Note: we have neglected queuing delays.

Each router will have its own d_trans, d_prop, d_proc hence this formula gives a rough estimate.