I am reading Kurose Computer Networking book 8e, on page number 57, under 1.3.2 Circuit Switching
Because it link has $4$ circuits, for each link used by the end-to-end connection, the connection gets $\frac{1}{4}$ of the link's total transmission capacity for the duration of connection.
In the context of circuit switching, each link will reserve the network session along with transmission rate. Why does the transmission rate in the reserved link gets divided when more concurrent connections are established? Why does adding more will interfere to that particular link?
In the above example let's say if there is a new host establishes from the bottom left side, and it establishes some another link, why does the it will drop the bandwitdh of already established link to $\frac{1}{4}$ (also shouldn't it be $\frac{1}{2}$?)?
