Q48

Consider the entries shown below in the forwarding table of an $\text{IP}$ router. Each entry consists of an $\text{IP}$ prefix and the corresponding next hop router for packets whose destination $\text{IP}$ address matches the prefix. The notation " /$\mathrm{N}$ " in a prefix indicates a subnet mask with the most significant $\mathrm{N}$ bits set to $1$.

$$\begin{array}{|ll|ll|} \hline \textbf{Prefix} && \textbf{Next hop router} \\\hline \text{10.1.1.0 / 24} && \text{R1} \\\hline \text{10.1.1.128 / 25}&& \text{R2} \\\hline \text{10.1.1.64 / 26}&& \text{R3} \\\hline \text{10.1.1.192 / 26}&& \text{R4} \\\hline \end{array}$$

This router forwards $20$ packets each to $5$ hosts. The $\text{IP}$ addresses of the hosts are $10.1.1.16, 10.1.1.72, 10.1.1.132, 10.1.1.191,$ and $10.1.1.205$. The number of packets forwarded via the next hop router $\mathrm{R} 2$ is __________.