How do I configure the SSDP TTL?

[wot-j]

I really like the features offered by Asset UPnP. However, I need a UPnP control point that can be seen across a router. From a wireshark capture, it looks like Asset sets the SSDP multicast TTL to 1 which keeps the NOTIFY messages from being seen beyond the local sub-net. A TTL of 2 would be enough for what I need but I don't see a way to set this value.

What do I need to do to set the SSDP multicast TTL to 2?

Thanks

[Spoon]

Re: How do I configure the SSDP TTL?

UPnP will not work across different subnets of a network, some control points allow you to set the url of the upnp server direct (such as PlugPlayer).

[wot-j]

Re: How do I configure the SSDP TTL?

Can you point me to the documentation that says UPnP will not work across different subnets please?

From what I could gather from the "UPnP Device Architecture 1.1" document, UPnP device discovery should be able to cross network segments. The document talks specifically about multicast TTL and forwarding traffic through a router. The document also states "the time-to-live (TTL) of each IP packet for each multicast message SHOULD default to 2 and SHOULD be configurable." If this document is not valid or has been superseded please let me know.

Thanks

[Spoon]

Re: How do I configure the SSDP TTL?

I should correct my statement - Asset will not work across subnets, as we build ontop of a standard library to do the low level stuff.

[wot-j]

Re: How do I configure the SSDP TTL?

If you don't mind me asking... what library do you use? I'd like to work with the library owners to get the functionality added.

[Spoon]

Re: How do I configure the SSDP TTL?

Platinum (except we heavily modified it), if you can point to the section we might make the mod.

[wot-j]

Re: How do I configure the SSDP TTL?

Looking at the Platinum source code, the relevant section appears to be within the PltSsdp.cpp module. Specifically, within the PLT_SsdpAnnounceInterfaceIterator class there is a line " multicast_socket.SetTimeToLive(4);".

Since the default TTL here seems to be 4, I'm wondering if you are using a different method to initiate a SSDP NOTIFY?

[Spoon]

Re: How do I configure the SSDP TTL?

Our version is older and does not have this code, I will make a note to look at when we are able to (R4.1 is now final and we cannot make this change now as it might have unintended consequences).