<aside> 💡 N = no. of hops L = Message length, in bits B = Data rate (Bandwidth) P = Fixed packet size, in bits H = Overhead (header) bits per packet S = Call setup time D = propagation delay per hop in seconds

</aside>

Circuit Switching

<aside> 💡 Steps

$$ \text{End to End Delay} = \text{Call setup} + \text{Propagation delay} + \text{Message time} $$

$$ \text{Propagation Delay } = D *N $$

</aside>

Packet Switching

Virtual Switching

<aside> 💡 Steps

$$ \text{no. of packets} = \frac{L}{P} $$

$$ \text{packet size} = P + H $$

$$ \text{Packet Time} = \frac{\text{Packet Size}}{B} $$

$$ \text{End to End Delay for one packet} = \text{Call setup} + \text{Propagation delay} + \text{Packet time} $$

$$ \text{End to End Delay for all packets} = \text{End to End Delay for one packet } * \text{ No. of Packets} $$

</aside>

Datagram

<aside> 💡 Steps

$$ \text{End to End Delay} = \text{End to End Delay of Virtual Swiching} - \text{Call Set Up} $$

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FHSS System

$$ \text {No . of hops} = \frac{W_s}{f_d} $$

$$ \text{The Miniumm no. of PN bits} = \log_2{\text{(No. of pf hops)}} $$