Present brief responses to every question as follows:- Name the uses of a Channel Service Unit/Data Service Unit (CSU/DSU). How do they function in the business setting?- Integrated Services Digital Networks (ISDNs) are applied in places that do not have Digital Subscriber Line (DSL) or cable modem connections. The options may be analog modems or an Integrated Services Digital Networks (ISDN) connection in those remote places. Make a description of the three (3) advantages Integrated Services Digital Networks (ISDNs) against regular dial-up modem connections.- Examine in order to note the similarities or differences of packet and circuit switching. What is the one usually employed? What are the pros and cons between the two?- Illustrate the three major kinds of firewalls. Give explanation how each kind safeguards the network. Resolve the firewall that is most proficient and explain the reasons.