Consider the circuit-switched network in Figure 1.13. Recall that there are 4 ci
ID: 3784285 • Letter: C
Question
Consider the circuit-switched network in Figure 1.13. Recall that there are 4 circuits on each link. Label the four switches A, B, C and D, going in the clockwise direction. What is the maximum number of simultaneous connections that can be in progress at any one time in this network? Suppose that all connections are between switches A and C. What is the maximum number of simultaneous connections that can be in progress? Suppose we want to make four connections between switches A and C, and another four connections between switches B and D. Can route these calls through the four links to accommodate all eight connections?Explanation / Answer
a)
Between the switch in the upper left and the switch in the upper right we can have 4 connections. Similarly we can have four connections between each of the 3 other pairs of adjacent switches. Thus, 16 simultaneous connections can be in progress at any one time on the network because there are 4 links.
You can use the expression 4n, where n represents the number of links to solve this.
b)
We can 4 connections passing through the switch in the upper-right-hand corner and another 4 connections passing through the switch in the lower-lefthand corner. Thus 8 simultaneous connections can be in progress between switches A and C because 4 can go from A through B to C. Plus another 4 can go from A through D to C.
c)
Yes, we can.
The 4 connections from A-C are as follows:
1)Wire 1 from A-B-C
2)Wire 2 from A-B-C
3)Wire 1 from A-D-C
4)Wire 2 from A-D-C
The 4 connections from B-D are as follows:
1) Wire 3 from B-A-D
2)Wire 4 from B-A-D
3)Wire 3 from B-C-D
4)Wire 4 from B-C-D