DES-3326S Layer 3 Fast Ethernet Switch User’s Guide
Switch Management and Operating Concepts
131
Router A
Router B
Router D
128.213.0.0
192.213.11.0
222.211.10.0
0
10
5
5
10
10
10
Router C
Figure 5-20. Constructing a Shortest Path Tree
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:
