 I had fun reading about heralds adventures in pacific ocean. What I learned was, these fishermen have a route table called dinaro and they exchange it with each other and update the information and they store numbers as the measure of distance between the islands. For example, all the neighboring islands from my island can be can have a number as 1 which means that it is directly traversable from my island and if I give that to one of my neighbor, he would update the distance to that island as 2 so that it is traversable using one hop or he should come to my island first and then go to that island, something like that. And in case there are any changes in the island to island links, so what they can do is they are able to immediately advertise it via sharing this information to the other island. So they are able to find out different routes. For example, the pirate example that was there and they were able to change okay, they could take a different route because the pirates were there. So that was quite interesting when we look at the analogy. Now there are many optimizations which can be performed in such a system also. For example, the router could also share the distance to the next hop as part of the information that it shares. The router could share other cost metrics along with this information. We will see soon how all this happens in a real network.