Partial synchrony assumes that messages between honest participants are not lost. This assumption, if I understand correctly, is needed for liveness. How is this guaranteed at network layer? (Given the big number of participants, having direct links between all participants does not seem as a feasible solution.)
Found this in the paper about Ouroboros Genesis:
Communication. The parties interact which each other by means of a network of eventual delivery unicast channels —informally, every party Up has an open incoming-connections interface where he might receive messages on from arbitrary other parties. This captures the natural joining procedure of real-worlds blockchains where new parties find a point of contact and use it to communicate with other parties by means of a gossiping (flooding) protocol. As argued in  assuming the honest parties are strongly connected, this netowrk can be used to build the (UC version of the) standard multicast network with eventual delivery assumed in [16, 26, 21].
Could someone confirm if this is a possible answer to my question?
Hi! The “Ouroboros Praos” paper is solely devoted to describing the protocol under the partial synchronicity, so please check it out: https://eprint.iacr.org/2017/573
Basically the safety guarantees within it work as a gradient, where it gracefully degrades from being as secure as absolutely synchronous setting down to requiring up to 2/3-ds of the honest participation in the worst case, as synchronicity worsens.
Hi, thanks, but i was asking about liveness and about the network layer…
Ah! Sorry 'bout that, missed the specifics
Yes, this description looks like the best to date on this particular matter