Networking$[$marks: $6]$ Q$4.$ Consider the diagram below. Link $1$ has length L$1m($where $m$ stands for meters$)$ and allows

packets to be propagated at speed S$1($m$/$s$),$ while Link $2$ has length L$2$ m but it only allows packets to be

propagated at speed S$2($m$/$s$)($because two links are made of different materials$).$ Link $1$ has transmission rate

T$1($bits$/$s$)$ and Link $2$ has transmission rate T$2($bits$/$s$).$

Assuming nodes can send and receive bits at full rate and ignoring processing delay, consider the following

scenarios:

a$)$ How long would it take to send a packet of $500$ Bytes from Node A to Node B given T$1=10000,$ L$1=$

$100000,$ and $S1=2\mathrm{.}5*{10}^8?$

b$)$ Compute RTT $($round trip time$)$ for a packet of B Bytes sent from Node A to Node C $($packet gets

transmitted back from Node $C$ immediately after Node $C$ receives it$).$

c$)$ At time $0,$ Node A sends packet P$1$ with D$1$ Bytes and then it sends another packet P$2$ with D$2$ Bytes

immediately after it pushes all bits of $P1$ onto Link $1.$ When will Node $C$ receive the last bit of $P2?$

d$)$ At time $0,$ Node A sends packet P$1$ with D$1$ Bytes and then it sends another packet P$2$ with D$2$ Bytes

immediately after it pushes all bits of P$1$ onto Link $1.$ When will Node C receive the last bit of P$2?$