Question

token is 64 bytes long (the 10-Mbps Ethernet minimum packet size), what is the average wait to receive the token on an idle network with 40 stations? (The average number of stations the token must pass through is 40/2 = 20.

Answer 1

Given that,

Token is 64 bytes long

The average number of stations that the token must pass = 20

We need to calculate the transmission delay for token

Using formula of transmission delay

$Transmission\ delay=\dfrac{token\ size}{minimum\ size}$

Put the value into the formula

$Transmission\ delay=\dfrac{64\ bytes}{10\ Mbps}$

$Transmission\ delay=\dfrac{64\times8}{10\times10^6}$

$Transmission\ delay=0.0000512\ sec$

$Transmission\ delay=5.12\times10^{-5}\ sec$

We need to calculate the average wait to receive token on an idle network with 40 stations

Using formula of average wait

$\text{average wait to receive token}=\text{average number of stations that the token must pass}\times transmission\ delay$

Put the value into the formula

$\text{average wait to receive token}=20\times5.12\times10^{-5}$

$\text{average wait to receive token}= 0.001024\ sec$

$\text{average wait to receive token}= 1.024\ ms$

Hence, The average wait to receive token on an idle network with 40 stations is 1.024 ms.