So there are 13 nodes to begin IEWB?

1        R1

2        R2

3        R3

4        R4

5        R5

6        R6

7        SW1

8        SW2

9        SW3

10      SW4

11      BB1, aka FRSW

12      BB2

13      BB3

Little bird told me someone might separate BB1 and FRSW.

They use 2 nodes for them.

Total is 14.