D-Link DXS-3326GSR Manual page 149

Shortest Path Tree
To build Router A's shortest path tree for the network diagramed below, Router A is put at the root of the tree and the
smallest cost link to each destination network is calculated.
The diagram above shows the network from the viewpoint of Router A. Router A can reach 192.213.11.0 through Router B
with a cost of 10+5=15. Router A can reach 222.211.10.0 through Router C with a cost of 10+10=20. Router A can also
reach 222.211.10.0 through Router B and Router D with a cost of 10+5+10=25, but the cost is higher than the route
through Router C. This higher-cost route will not be included in the Router A's shortest path tree. The resulting tree will
look like this:
DXS-3326GSR Gigabit Layer 3 Switch
Figure 7- 15. Constructing a Shortest Path Tree
128.213.0.0
5
192.213.11.0
Figure 7- 16. Constructing a Shortest Path Tree
Router A
0
10
Router B
5
Router D
10
222.211.10.0
136
10
Router C
10