I am looking for an analysis of practical mix networks with server downtime.
For example, if a message is supposed to go from A -> B -> C -> D, what happens if B wants to send the message but C is offline temporarily?
This could be a stop-and-go mix network so holding onto a message longer is OK, but I am wondering whether there's any paper analyzing this sort of thing? For instance, how does it affect anonymity, how does B know when to retry sending it, etc?
Or what if C goes offline permanently, is the message lost? Is there a mix network protocol for resilience in this case?