need explaination (a) A connectionless protocol, such as Ethernet, defines the route of a packet through source and destination addresses. However, a connection-oriented protocol, such as ATM, defines...

need explaination

(a)

A connectionless protocol, such as Ethernet, defines the route of a packet through source and destination addresses. However, a connection-oriented protocol, such as ATM, defines the route of a cell through virtual connection identifiers (VPIs and VCIs). Could you explain this statement?

(b)

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  IP addresses can be given to devices statically or dynamically, Could you provide an example? Why IPv4 facing crisis? And how to get rid of these IP crisis?