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

Computer network

A computer network, often simply referred to as a network, is a collection of hardware components and computers interconnected by communication channels that allow sharing of resources and information....

 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

Transmission delay

In a network based on packet switching, transmission delay is the amount of time required to push all of the packet's bits into the wire. In other words, this is the delay caused by the data-rate of the link....

 

d_prop= propagation delay

Propagation delay

Propagation delay is a technical term that can have a different meaning depending on the context. It can relate to networking, electronics or physics...

 

d_proc= processing delay

Processing delay

In a network based on packet switching, processing delay is the time it takes routers to process the packet header. Processing delay is a key component in network 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.