Our team is implementing Libp2p in C++ language, and currently, I am working on the Multiselect protocol. So, a little question has appeared: for example, one node sends all protocols it supports (as a response to ls), and none of them is supported by the other.
What should the other node do? How to say that it is impossible to communicate and close the connection? Send na as a response to ls? Such a case is not documented here, so I am not sure.