```
 A transit network is represented by a graph vertex having both incoming and outgoing edges

```

I can't say that this representation makes sense for me. Can anybody explain why the OSPF algorithm needs this?

Here is an exaple [![enter image description here](https://i.stack.imgur.com/303Kd.jpg)](https://i.stack.imgur.com/303Kd.jpg)

On top of the above some edges in that graph seem to have different weights for the same link