Cheol H. Koo

No. I am not seeing any particular problem when the first bundle source node have a previous node block (i.e. itself). As far as I know, the previous node block extension was invented to provide hopefully useful information to a routing protocol; so the first bundle source node definitely can have a previous node indicating itself, and that may be advantageous in a certain routing algorithms (perhaps flooding or epidemic ?) I think. I will be on the side of those whose action is to modify the current...

Thanks for the explanation about how ION works with insertion of a previous node. I issued this because insertion of a previous node at the starting node, i.e. the first node forwarding a bundle, is NOT expected as RFC-9171 describes at 4.4.1. Previous Node (see my initial comment above). Hope this helps if you want my clarification to my comment.

Creation of Previous Node ext. block in starting (source) node