Your friend has an idea for a new congestion control algorithm for TCP$.$ Your friend thinks that routers

should notify TCP senders before the router's buffer becomes full so the TCP sender can slow down

before packets are lost. The router will do this by looking at its buffer size each time a new packet

arrives. If the router's buffer is more than $80\%$ full $($less than $20\%$ left$),$ then the router will send a

"slow down" message to the current packet's sender and process the packet normally. If the router's

buffer is less than $80\%$ full, then the router will process the packet normally and not send a "slow down"

message. You don't think this is a good idea. Answer the following questions about the problems you

notice with this idea.

$($a$)[5$ points$]$ What fundamental problem is there in asking the router to send a message to the TCP

sender$?$

$($b$)[5$ points$]$ Why would this idea not reduce congestion at the routers in the network?

$($c$)[5$ points$]$ What is one complication you see in implementing this idea in a TCP sender$?$