Hi everybody,
I have a PC which is connected with WLAN and LAN to the same router. As soon as I disconnect the LAN cable the DDS connection stops working after 30s although I remain in the same network through wifi and a tcp videostream as well as ping to the router still work fine.
Discovery and initial peers are shmem, udpv4://localhost and multicast
Furthermore If I start the application with wifi only and then connect the LAN cable the DDS connection also stops working as soon as I disable the Wireless Network. There happens no automatic swap to the LAN interface for the DDS Participant. But a periodic ping to the switch works fine through the whole time. Wifi 3-6 ms and LAN <1ms.
How can I confige my QoS so this szenario works? "Two redundant and only limited available NICs to the same network"
Tanks in advance
Sönke
Hi Sonke,
What operting system are you using?
Regarding the first point. My first guess would be that the WLAN network does not configure to support multicast (however see later as it seems that in your case you do have multicast). If that was the case then the periodic "multicast announcements" that are sent would not be received and this would be interpreted by the discovery protocol as a "loss of liveliness" meaning the other application has left the system. The default settings for the participant annoucement period is 30 seconds. However I would not expect the connection to be lost after 30 seconds as the default value of the partcipant lease duration (i.e. the length of time without announcements after which a participant is considered lost) is 100 seconds. Did you modify either of these two values?
But in your second statement you seem to indicate that you can run with the WLAN only. In this case your WLAN must be relaying multicast... So what I stated above does not justify what you are seeing...
Regading the second point Connext DDS will only detect the network interfaces that are up when the application starts. So if you connect the LAN after the application has been started then it will not switch to this new interface. However we are working on a feature that will address this situation. If you are interested in it you should contact our field engineers at sales@rti.com and they can give you more details on when this will be available.
Is it possible that somehow the disconnection of the LAN causes the router to also asign a differnt IP address to the WLAN? If so that would explain yoru first problem.
Also I think we have recently detected a windows bug where the IPv6 transport gives some error messages about 30 seconds after disconnect an interface becasue there is an event that is not properly handled. But it seems that you are using IPv4 not IPv6 right?
Regards,
Gerardo
Hi Gerardo,
thank you for your thoughts. The OS is Windows 7 Pro. I did not adjust any Timings, so all livelinesses and timeouts should be the default value.
I have no DHCP and all IPs are static.
The interesting thing is that I can still see the packets in the spy of a third pc on the same network. But they are not handled anymore by my other application which worked before.
IPv6 is not configured and I assume that it is not supported by the access point. But It is also not disabled in the network interface properties of the Windows PC
PS: I am using Reliable transportation.
Theese are the discovery initial peers settings:
<-element>builtin.shmem://</element>
<-element>builtin.udpv4://localhost</element>
<element>builtin.udpv4://18.1.4.30</element>
<element>builtin.udpv4://239.255.0.1</element>
And the inerfaces:
<name>dds.transport.UDPv4.builtin.parent.allow_interfaces</name>
<value>192.*,10.*,11.*,16.*,18.*</value>
<name>dds.transport.UDPv4.builtin.parent.deny_interfaces</name>
<value>17.*</value>
How can I configure the discovery and transportation so that the LAN and WLAN connections do not interfere?
regards Sönke