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ONDA CERO turns IP It was this summer when Onda Cero finished an ambitious project that took a few years around the house: the unification of data and audio on a single network. We have come to the headquarters in Madrid to talk to them about this integration. Interview with Nuria Dominguez, Technical Director of ONDA CERO It was an ambitious and cutting edge project. How did it start? At the time when the project was raised ten years ago, we were operating in Frame Relay data lines and it was not feasible for the amount of delay, jitter and bandwidth requirements, integrate data and audio on that network. So the first step was to restructure the data network more consistently with what we wanted. In the permanent audio network (contribution and satellite backup) we were working with 15 kHz analog lines. What we did first was reorder the data lines and pass the audio lines to the same operator as the data. We leave it all tuned to what we needed, a base from which to work. That’s why it has been a long project; it took time to improve the network and management of everything. A problem we encountered, which is logical, is that telecommunication operators understand very well the data traffic, but the same does not occur with live audio. It is normal because they don’t consider a problem when the data packet comes with a small delay. But if we're talking about live audio that means audio cuts, which is obviously unacceptable. So we had to define how the new lines should be on the basis of getting the better audio performance, with quality of service and setting a jitter threshold. Two worlds colliding... They were two worlds, data and audio, we wanted to join and now I can say that they fit perfectly. We did not want to put into operation the audio data over the network until we were sure we had everything under control. You could not endanger the emission, which is sacred. That is why we did so many tests. Prodys, which has been our equipment supplier, has always been very open to everything we said to them, as was the operator Telefonica, although sometimes there was some dispute as is normal in this type of projects. Going on edge means you're going to find things nobody has seen before, like a connection working perfect through an ADSL but failing through a macroLAN, although it is assumed that the latter has a guaranteed bandwidth. We realized that actually the data network was not designed or intended for audio and then decided to use FEC. There are many intermediate routers and equipment so that if a data packet is having problems, the route is changed. For an email, this means nothing but for broadcasting, it means a lot as the live audio is going to be affected. We solved this using FEC, which supposed to double the contracted bandwidth. We included a clause in the contract with the operator to maintain the analog audio lines until the network was not fully deployed, so we could work without incident while we were solving the problems that were appearing. Now everything works over IP, all. We had problems with the maintenance of the permanent network in analog audio due to the age of the equipment used. It is a service that is no longer in our catalog and will expire when broadcasters who still use it decide to their networks. We could have chosen simply to change the permanent point to point network of analog audio lines by point to point digital network. That would have been more immediate and easier but at the cost of losing flexibility and money. Our advantage was that the data network was deployed and operational. There are colleagues from other stations that prefer separate networks, but it is much more expensive and in these times we must take advantage of technology to become more efficient. How was the change? The truth is that the change has not been traumatic; we expected more complications than we have had and these complications have been solved by all parties. It is true that IP audio is used by many people, but that your entire network relies on that is something that has not been done so far. We wanted the change to be as transparent as possible for sound technicians. That meant we had to automate the switching the codecs had to make, the IP addresses to call and the connections to be maintained. The project not only included the digitizing and unification of audio and data networks, but the connections automation. Still, we managed to get people to change a bit their working methods. It had long been working in the same way and bad habits had been acquired. For example, N-1 was not used because the delay in analog lines was negligible, but with digital communications, despite all the changes we have done and all that we have improved, you do need N -1. Training has been fundamental. We have given many courses because it is very important that everyone has the necessary technical information. Because the network we have now works better and sounds great, but you need to have the necessary knowledge, to do much teaching and involve everyone. So we had it all tied up before summer and we rushed, we did the change and cancelled the analog lines. We are working perfectly now. How is that network? It is a multipoint network, all can work with everyone. Before the audio network was point to point, connecting the headquarters with the header stations and these in turn with provincial stations and these with the local. If you wanted to interconnect delegations, you had to go by bridges between patch panels. The great thing in the integration we've done is that any two stations can be interconnected in a flexible and easy way with both data and audio without the expense of dedicated lines. What equipment mounted? have you We did many tests with different equipment and suppliers. The truth is that everyone is in a very high level. We finally chose Prodys because they accepted the challenge of adopting the changes we needed. Since the project was so pioneering it was not just to choose good equipment, but to choose a partner willing to help in any way necessary. We have installed various equipment of the Prodys Pronto family as ProntoNet, ProntoNet LC and Nereus, which is a chassis where multiple encoder cards can be fitted. The latter are aimed at facilities where many codecs are required because it is economically more profitable to have such chassis than several 1U equipments. In larger venues such as Madrid, Seville, Barcelona and Valencia a Nereus equipment installation has been made, which can rapidly expand by adding the cards as needed. Everything is scaled by the number of connections that can be made, using a very rational approach. The good thing about the equipment we have chosen and the network topology is that everything is perfectly scalable, so we decided to go to minimum and increase if necessary. To control all the ProntoNets we are using Prodys Control. With it we can connect at any time to a encoder whatsoever wherever it is. We also have an application to read all the data from the Prontonets to see if there is any alarm and to monitor the state of each codec. Prodys has worked hard in the integration of their equipment with our applications. It was critical to monitor real-time the state of everything, regardless of whether we could enter a remote station to see the equipment in detail. How do you commutations? make the We use the satellite as the primary channel for sending audio (main program) and disconnection data. When necessary, a command is sent to change to main, regional, provincial or local program. Thanks to the data network, disconnection commands can be sent from any delegation as all the broadcast equipment is interconnected and receive orders through both satellite and WAN. This has allowed the MCR to be released from this work it had to do for the entire broadcast network and has provided greater freedom to smaller centers. We designed which commutations had to be made depending on the type of disconnection and how and what data had to be received and sent to Madrid to see the status of equipment. Another great advantage of the network that we have implemented is that previously we were lost if the satellite fell. When this happened, the analog lines became operational through simple switching units that changed the line if a lack of satellite signal was detected, but we lost the disconnection data with everything that implies. Now, if we have an issue with the satellite, we are still having audio and you can send anything you want on the network losing absolutely no functionality. We have gained a lot. After everything you've learned and the good communication with the operator and the provider, will it be easier for those who go after you? The truth is that all people involved in this project have learned a lot. I imagine that all that knowledge will be useful for those who go behind. We have been at the forefront with a difficult goal. Telefónica has come to understand the needs and has adapted to what we found. Prodys has been very flexible to fit everything too, because even if the codec was wonderful, they had to do everything we asked for. If not, it was useless for us. It had to be able to do things like looking in the agenda, see the IP that had to change and do it; it was not just the audio. In this case they have heard us and they have done everything we asked them. From TM Broadcast, number 44. Pages 40 to 44. Translated from Spanish