Consider sending a message of $10,000$ bits from the source node $S$ to the destination node $D$ passing through the two routers $R 1$ and $R 2$ as shown in the figure. Each of the three links on the path has a propagation delay of $20\; \mathrm{~ms}$. Node $S$ has a transmission rate of $100 \;\mathrm{bits} / \mathrm{sec}$, and each of $R 1$ and $R 2$ has a transmission rate of $1000\; \mathrm{bits} / \mathrm{sec}$. Assume that: (i) each router uses store-and-forward packet switching; (ii) the size of the header is negligible compared to the packet size; (iii) except transmission and propagation delays, all other delay components are negligible.
- Find the end-to-end latency of the message when it is sent as a whole.
- Find the end-to-end latency of the message when it is broken into $10$ packets each of size $1000$ bits, and then transmitted to the destination.
