All paths between two devices

[Sofiane MESSAOUDI]

Hello,

Can anyone guide me how I can get all available paths between two devices ? I tried getPaths() but it returns the set of shortest paths, not all available paths. 

So i know that i should customize the onos java classes related to that but i can't find which class or parameter to changer exactly !!! 

Thanks

Sofiane

[Hadi Kahraman]

ONOS path computation is based on Dijkstra algorithm, which computes the "shortest" (minimum total "cost") path only:

DijkstraGraphSearch.java

Five years ago we (Argela) developed a modified algorithm calculating best N paths based on multi-parameter cost computation functions. It was a military project, therefore I cannot share the code.

If someone else didn't add similar functionality to ONOS -which I don't know-, then you need to develop your own.

There is a KShortestPathsSearch class in ONOS, but it didn't work as expected. Maybe we were doing something wrong. Maybe it was fixed later. You can check it.

Sofiane MESSAOUDI <sofianem...@gmail.com>, 9 Mar 2022 Çar, 17:59 tarihinde şunu yazdı:

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[Sofiane MESSAOUDI]

Thank a lot hadi,

But i don't need any cost computation algorithm, i just need to return all the available paths between host 1 and host 2 or device i and device j, that's all and i don't know what to do!or to change in DijkstraGraphSearch.java for example.

Regards,

Sofiane

[Eder Ollora]

Hi Sofiane,

I imagine that the reason why there is no pathService.getAllPossiblePaths(Node_a, Node_b) is because it is very hard to compute (here some info on why). I do not remember how the LinkWeigher works in ONOS but in case this variable is used to return paths that match a particular metric, then why not use it?. I probably cannot give an extended explanation about it but you can ask question if you decide to test it.

The way to use the LinkWeigher is briefly explained by Pier here: https://groups.google.com/a/onosproject.org/g/onos-dev/c/38IL1y3-TmY

Cheers