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I need a way for my application to find someone with the same application on a local network.

But can't find the docs to use a protocol like SSPD. It says its UDP on port 1900 and the ip 239.255.255.250.

It also says it can use NOTIFY and M-SEARCH.

But that is it. I've hit a wall. And I need some guidence.

OVERVIEW

Trying to make my apps automatically find each other and exchange ip/names on a local network so they can talk to each other p2p-style without a connection broker.

guestedForAnwser
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    Seriously, first result when you use google with **SSPD protocol**. – Marcus Müller Sep 06 '15 at 20:36
  • What do you mean first result? I get a wikipage. – guestedForAnwser Sep 06 '15 at 20:56
  • yes, indeed, and that gives you plenty of links, pointers, words to google for, including the IETF draft defining that protocol. – Marcus Müller Sep 06 '15 at 20:57
  • Hey, by the way, friendly hint: your Nickname probably has a typo: Answer is spelled with s-w, not w-s, and guested is not really used that way. :) No criticism, just hint! – Marcus Müller Sep 06 '15 at 20:59
  • I read the pages. And they have sent me around in the same loop for hours. You have to keep in mind that not everyone is on the same level as you. So stuff that somewhat feels easy for you, might prove much harder for others. I might be asking dumb questions, idk. But your bad attitude is more destructive to the community. – guestedForAnwser Sep 06 '15 at 21:05
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    I know this isn't easy, really! But still, it's a complex standard, and you will have to *read* the draft to *understand* the draft to *know what you're doing*; I don't think anyone can offer you a shortcut for that. – Marcus Müller Sep 06 '15 at 21:07
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    I did not ask for shortcuts nor anwsers. But guidance. Like "read this article" or "lookup this (term)" or "try these apps out, it might not be the experience you're looking for" or "SSDP is wildy insecure, look into (w/e) instead". – guestedForAnwser Sep 06 '15 at 21:14

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The UPnP Device Architecture reference contains the de-facto SSDP reference: it's very similar to the IETF spec and has dozens of well tested implementations already. Chapter 1 contains everything needed to implement SSDP, assuming you know how to send and receive multicast and unicast UDP messages.

My advice on implementing SSDP: Don't. It may look simple but there are a lot of gotchas on the way. Find a library or service that does SSDP for you. If you are on linux I suggest GSSDP (reference, code) (but I'm a bit biased having worked on it). I would assume other platforms have similar libraries.

Jussi Kukkonen
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