D-Link DES-3326 manual Constructing a Shortest Path Tree

DES-3326 Layer 3 Fast Ethernet Switch User’s Guide

Router A

128.213.0.0

Router B

192.128.11.0 Router C

Router D

222.211.10.0

Figure 5-22. Constructing a Shortest Path Tree

Router A
0
128.213.0.0	10
10

Router B	Router C
5
5
192.213.11.0	10
Router D
10

222.211.10.0

Figure 5-23. 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:

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