Suppose you want to develop a new protocol so that Ethernet switches participating in a VLAN all keep track of the VLAN $$color$$ associated with every destination in their forwarding tables. Assume that each switch knows which of its ports $($interfaces$)$ connect to other switches and which may connect to hosts, and in the latter case knows the color assigned to that port.

$($a$).$ Suggest a way by which switches might propagate this destination$-$color information to other switches.

$($b$).$ What must be done if a port formerly reserved for connection to another switch is now used for a host?