The following parameters are defined for a switching network:

N $=4=$ number of hops between two given end systems

L $=6000=$ message length in bits

B $=$ data rate, in bits per second $($bps$),$ on all links

P $=1080=$ fixed packet size, in bits

H $=80=$ overhead $($header$)$ bits per packet

S $=0\mathrm{.}2=$ call setup time $($circuit switching or virtual circuit$)$ in seconds

T $=0\mathrm{.}02=$ call teardown time $($circuit switching or virtual circuit$)$ in seconds

D $=0\mathrm{.}001=$ propagation delay per hop in seconds

Question $1$

If L is not the same as above but is instead L$=13000$ bits $($all other parameters the same$),$ how many packets are required?

Question$2$

Given is a situation with the above parameters $($including back to L$=6000),$ but with a data rate of $7\mathrm{.}3$ kbps $($that is thousands of bits per second$).$ Assume that there are no acknowledgment packets, but do not ignore teardown times. Ignore processing delay at the nodes. Compute the end$-$to$-$end delay to fully and properly complete virtual circuit packet switching.

Question $3$

Use the scenario from Question $2,$ except there is a nonzero processing delay for both virtual circuit switching $($Tproc$=$TVC$)$ and datagram switching $($Tproc$=$Tdat$).$ Assume the processing delay for a virtual circuit switching at each node is TVC$=5\mathrm{.}2$ ms$.($that is$,$ milliseconds$).$ Now compare with datagram packet switching. Find the minimum datagram processing time $($Tdat$)$ in milliseconds for which virtual circuit switching has a lower end$-$to$-$end delay than datagram packet switching. Use setup time$=200$ ms$.$ and teardown time$=20$ ms$.$ You must include both setup and teardown time.

Question $4$

Given the same parameters as Question $2($including T$$dat$=0)$ and now use $11\mathrm{.}7$ kbps$,$ what is the minimum number of hops N where circuit switching has lower end$-$to$-$end delay than datagram switching? Here use setup time S $=0\mathrm{.}35$ sec and teardown time T $=0\mathrm{.}02$ sec$.$