Two edge routers $($R$1$ and R$2)$ are connected to one core router $($C$1).$ Packets entering R$1$ at rate $100$ pkts$/$sec and R$2$ are rate $120$ pkts$/$sec$.$ Both the edge routers have a service capacity of $150$ pkts$/$sec$.$ The core router has a service capacity of $400$ pkts$/$sec$.$ After being served at R$1,$ packets enter C$1$ with probability $0\mathrm{.}6.$ After being served at R$2,$ packets enter C$1$ with probability $0\mathrm{.}7.$ Fresh packets arrive at the C$1$ at rate $50$ pkts$/$sec$.$