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Routing Table Principle |
Example |
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Every router makes its decision based only on the information in its own routing table |
R1 can only forward packets using its own routing table R1 does not know what routes are in the routing tables of other routers |
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Routing Tables of different Routers do not have to be the same |
Just because R1 has route in its routing table to a network in the internet via R2, that does not mean that R2 knows about that same network |
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Routing information about a path does not provide return routing information |
R1 receives a packet with the destination IP address of PC1 and the source IP address of PC3
This doesn’t necessarily mean that it knows how to forward packets originating from PC1 back to PC3 |