D-Link dxs-3350sr Installation & User Manual page 152

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-3350SR Gigabit Layer 3 Switch
Figure 23- 1. Constructing a Shortest Path Tree
128.213.0.0
5
192.213.11.0
Figure 23- 2. Constructing a Shortest Path Tree
Router A
0
10
Router B
5
Router D
10
222.211.10.0
143
10
Router C
10