Suppose a router has $N$ input ports and $N$ output ports, where all these ports have the same line speed, $R_{\text{l}\text{i}\text{n}\text{e}}.$ The switching fabric has a transfer rate $R_{\text{s}\text{w}\text{i}\text{t}\text{c}\text{h}\text{,}},$ which denotes the rate at which packets can be moved from input port to output port.

$($a$)$ Will packet loss occur at the input port if $R_{\text{s}\text{w}\text{i}\text{t}\text{c}\text{h}}>N{R}_{\text{l}\text{i}\text{n}\text{e}}{R}_{\text{s}\text{w}\text{i}\text{t}\text{c}\text{h}}?$

$(b)$ Will packet loss occur $at$ the input port $if{R}_{\text{s}\text{w}\text{i}\text{t}\text{c}\text{h}}>N{R}_{\text{l}\text{i}\text{n}\text{e}}?(The$ symbol $$ denotes 'much greater than'$)$

$(c)$ Can packet loss $at$ output ports $be$ eliminated $by$ increasing the switching fabric speed?

$(d)$ Does HOL Blocking occur $in$ input ports $or$ output ports?