Switching types $(2+2=4$ points$).$ For each question below, your answer must be one of $$circuit$,$message$,$ or $$packet$,$ along with a justification.

$($a$)$ Suppose you$$d like to design a network with routers that need to support application con$-$ versations that transfer a lot of data with strong performance guarantees. What kind of switching would you use for the network$$s routers? Please justify your answer $(2$ points$).$

$($b$)$ Suppose, instead, your network must support applications that move a small number of application$-$level messages between a large number of pairs of endpoints. Each application$-$level message may be very large. Further, even if the entire message isn$$t received yet, it is helpful for the applications to transfer smaller portions of the messages as early as possible to the receiving endpoints. What kind of switching would you build into the network$$s routers? Please justify your answer $(2$ points$).$