For the protocol in section 17.3, what is a reasonable lifetime to use for the keys K/a? Why? What bad things could happen if the lifetime is longer? What bad things could happen if the lifetime is shorter?

What is domain name system (dns)? allows dynamic ip address allocation so users do not have to have a preconfigured ip address to use the network converts ip addresses into domains, or identifying labels that use a variety of recognizable naming conventions the efficient coexistence of telephone, video, and data communication within a single network, offering convenience and flexibility not possible with separate infrastructures the integration of communication channels into a single service