Dirk Meyer wrote: > Peter Saint-Andre wrote: >> Alban Crequy wrote: >>> However, if the 2 clients both implement XEP-030 Service Discovery and >>> XEP-0115 Entity Capabilities, they will both initiate a stream in order >>> to send a discovery request as soon as they appear online via DNS-SD, >>> without user intervention. >> Really? I thought we were advertising caps in DNS TXT. See the "ver" >> record here: >> >> http://xmpp.org/extensions/xep-0174.html#registrar-linklocal-reg >> >> So I think that opening a stream to everyone who appears online via >> DNS-SD is a bad idea. >> >> Thus I would say that if you know the "ver", you'll know what the other >> entity is. But if you don't know the "ver", don't automatically open a >> stream to the other entity just to do all the caps lookup magic via disco. > > Thinking of my bot-to-bot communication scenario it may happen. I client > may want to know if another media server got online to present it in the > user interface. If the ver is not known, it has to open a stream to > discovery what the ver means. > >>> Do we want this to happen? >> No. >> >>> Sjoerd suggested on IRC to add random slack >>> time before initiating a stream to avoid it. > >> That is one possibility. > > We have a solution for that in xtls, maybe we should copy it to XEP-0246 > End-to-End XML Streams: > > | It is possible that both parties may attempt to start the use of XTLS > | at the same time [13], in which case one party may receive an XTLS > | start stanza from the other party after it has sent such an XTLS start > | stanza but before receiving a response. In this case, one of the > | initiation requests shall be considered to have higher priority than > | the other, and the party that receives the lower priority initiation > | request shall return a <conflict/> stanza error in response to the > | lower priority request. The higher priority request MUST be considered > | the request that is generated by the party whose JID is sorted before > | the other party when the JIDs of both parties are sorted using > | "i;octet" collation as specified in Section 9.3 of RFC 4790 [14].
Yes, that would work for XEP-0174, too. Thanks for pointing it out! Peter -- Peter Saint-Andre https://stpeter.im/
