# UDP Network? **URL:** \ **Category:** GNU Radio\ **Created:** [July 23, 2014, 7:44pm UTC](https://www.ruby-forum.com/t/udp-network/231150 "2014-07-23T19:44:16Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![addis\_a](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/c4cdca/32.png) [@addis\_a](https://www.ruby-forum.com/u/addis_a)\ **Post date:** [July 23, 2014, 7:44pm UTC](https://www.ruby-forum.com/t/udp-network/231150/1 "2014-07-23T19:44:16Z")
Hey everyone, I’m currently trying to send the same generated signal from two usrp’s to a third usrp/host. On the transmitting side, I can clearly see both signals going out, but on the receiving side, I am getting a runtime error. On the UDP connection on the transmitting side, I have both destination addresses being the third usrp/host, and on the receiving end side, I incorporated two UDP source blocks (since one block can only take in one input) and have both of their addresses being the the same destination address as the transmitting side (seeing that when dealing with UDP, both sides have to have the same address in order to know where they will send and pick up the signal). Would my problem be that on my receiving side, I have both UDP sources with the same address (as I would not know which UDP source is receiving which signal)? Thanks in advance, Marcus ---
**Author:** ![WardS\_Marcus\_D](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/w/ccd318/32.png) [@WardS\_Marcus\_D](https://www.ruby-forum.com/u/WardS_Marcus_D)\ **Post date:** [July 23, 2014, 8:09pm UTC](https://www.ruby-forum.com/t/udp-network/231150/2 "2014-07-23T20:09:40Z")
Do you have different ports for your different UDP streams? Greetings, Marcus ---
**Author:** ![WardS\_Marcus\_D](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/w/ccd318/32.png) [@WardS\_Marcus\_D](https://www.ruby-forum.com/u/WardS_Marcus_D)\ **Post date:** [July 23, 2014, 8:49pm UTC](https://www.ruby-forum.com/t/udp-network/231150/3 "2014-07-23T20:49:34Z")
Hm, strange. Can you do "ncat --listen --udp " for both, 1234 and 1240? (If it works, kill it with ctrl-c). If it doesn’t allow you to bind to that address, run “ip addr” to make sure you have actually assigned that address to your network interface. The error indicates that the host you’re running on doesn’t actually have the IP address you set in the UDP sources; are you doing NAT somewhere in between? Greetings, Marcus ---
**Author:** ![WardS\_Marcus\_D](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/w/ccd318/32.png) [@WardS\_Marcus\_D](https://www.ruby-forum.com/u/WardS_Marcus_D)\ **Post date:** [July 23, 2014, 8:23pm UTC](https://www.ruby-forum.com/t/udp-network/231150/4 "2014-07-23T20:23:26Z")
Hey Marcus, Yes, I checked that and on the first UDP stream, I am using port 1234 while on the second UDP stream I am using port 1240 and I am still getting: Runtime Error:bind: Cannot Assign requested address From: discuss-gnuradio-bounces+marcus.ward=removed\_email\_address@domain.invalid [[mailto:discuss-gnuradio-bounces+marcus.ward=removed\_email\_address@domain.invalid](mailto:discuss-gnuradio-bounces+marcus.ward=removed_email_address@domain.invalid)] On Behalf Of Marcus M. Sent: Wednesday, July 23, 2014 2:08 PM To: removed\_email\_address@domain.invalid Subject: Re: [Discuss-gnuradio] UDP Network? Do you have different ports for your different UDP streams? Greetings, Marcus On 23.07.2014 19:42, Ward, Marcus D. wrote: Hey everyone, I’m currently trying to send the same generated signal from two usrp’s to a third usrp/host. On the transmitting side, I can clearly see both signals going out, but on the receiving side, I am getting a runtime error. On the UDP connection on the transmitting side, I have both destination addresses being the third usrp/host, and on the receiving end side, I incorporated two UDP source blocks (since one block can only take in one input) and have both of their addresses being the the same destination address as the transmitting side (seeing that when dealing with UDP, both sides have to have the same address in order to know where they will send and pick up the signal). Would my problem be that on my receiving side, I have both UDP sources with the same address (as I would not know which UDP source is receiving which signal)? Thanks in advance, Marcus * * * Discuss-gnuradio mailing list removed\_email\_address@domain.invalid[mailto:removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) [https://lists.gnu.org/mailman/listinfo/discuss-gnuradio](https://lists.gnu.org/mailman/listinfo/discuss-gnuradio)