Assuming UB has a campus$-$wide network, as illustrated in the figure. All hosts within the

network are connected to a UB Router. The UB router, in turn, links to the public Internet

router via a UB Access Link. Considering that hosts inside the UB network generate $50$ web

requests per second, with each web request having a total size of $10$ Mbit. The lengths and

capacities of the links between the Internet Server, Internet Router, and UB router are

depicted in the figure. It's important to note that the distance between hosts inside the UB

network and the UB router is negligible, assumed to be zero. All devices transmit based on

the store$-$and$-$forward strategy. The packet flows at the speed of light.

$1.$ Is there a queueing delay at the UB access link? Why? $(5$ points$)$

$2.$ Discuss the case if the capacity of the UB access link increases to $750$ Mbps$.(5$ points$)$

$3.$ If instead of increasing the access link capacity, we introduce a UB cache inside the

UB network, is there a queueing delay $($or potential congestion$)$ at the UB access link

given a caching hit rate of $60\%($the capacity of UB access link is $200$Mbps$.)$ Why? $(5$

points$)$

$4.$ Discuss if there are any changes if the hit rate rises to $70\%.($The capacity of UB access

link is $200$Mbps$.)(5$ points$)$