Network Requirements for IPTV and OTT Service
Where to start?
First thing each service provider should do when start planning to launch IPTV or OTT service, is to check if IP core or access network are ready for video streaming. There are requirements that need to be met in different parts of the network, from IP core routers, to DSLAMs and CPE devices. In this blog, I will give you a short overview of these requirements, to help you get started.
First you need to decide how to organize the IPTV assessment. Should you use in house network department or look for external consultants? If you have enough resources and expertise, with small guidance, you can do majority of the tasks on your own. However, I strongly recommend to engage external network consultants with extensive experiences in IPTV/OTT at least for a final review. This will give you an independent view of your network and interpretation of the measured results from the IPTV/OTT perspective.
“Does all the network and access equipment support multicast related requirements?”
After you define organization of the assessment, you can move to the technical requirements. With introduction of the IPTV in the network, in general, there are two main things you need to check: Is there enough bandwidth in all parts of your network to serve planned number of IPTV users and secondly, does all the network and access equipment support multicast related requirements and is ready for multicast and unicast streaming.
For checking the bandwidth requirements, you need to dimension your IPTV service, such as defining number of SD and HD TV channels, number of planned subscribers, VOD and nPVR concurrency. Based on these, you can calculate required bandwidth on each DSL line, in access network and in core IP network. In case you are not familiar with IPTV solution, you can get some basic overview in the blog How to start an IPTV/OTT Turnkey Solution?
Main difference between IPTV and OTT service is that for OTT, unicast streaming is used also for the Linear TV. This means, you don’t need to care about multicast support, but it generates bigger bandwidth requirements for your core network. Based on dimensioning of the TV service, you can plan several edge locations for streaming to offload your IP core network.
“Check your network architecture diagram and all the network connections and make sure there are no bottlenecks.”
You should carefully check your network architecture diagram and all the network connections and make sure there are no bottlenecks. Don’t forget to check these in all regions where you want to deploy IPTV and OTT service, to avoid situations of having plenty of bandwidth in the core, but struggling on the interconnection toward regional networks.
Regarding multicast, first check multicast availability across your whole network. Again, don’t forget to check all regions where you plan to offer IPTV service. Make a list of all different vendors and models of network equipment in your network, especially DSLAMs and DSL modems and verify that all equipment supports multicast. Check with the vendors for some best practices document regarding multicast support and make sure your configuration is really aligned with the best practise guidelines.
DSL modems are very frequently source of the issues with multicast streaming. Such issues take a lot of time for solving it in the production and heavily impacts on the satisfaction of your users. Specially with several different models and vendors it is hard to troubleshoot, so it is highly recommended to prepare and test your access network before a commercial launch. First thing worth checking is, if the SW installed on the modems supports multicast and all required features such as IGMP snooping. Secondly, make a detailed test with 2-3 concurrent multicast streams on the modem and running WiFi and multicast traffic at the same time, if such scenario will be used. The later, is usually an issue, without proper fine tuning of the modem configuration.
Even when you make all mentioned steps and prepare well for the IPTV launch, for sure you will face some streaming issues for a specific customers, based on the line quality or some other specifics. For such cases it is extremely important that your access maintenance team can fine tune DSL line parameters per specific subscriber.
“You need to have a tool showing you historical report on the DSL lines performance, per each DSL line.”
DSL Line Reporting
Another important thing about DSL lines is the reporting. You need to have a tool showing you historical report on the DSL lines performance, per each DSL line. This will give you a very good view on your DSL lines quality and readiness for IPTV in the assessment stage. I highly recommend you to get such reporting system, if you don’t have it already. In any case, you will need it, once you launch your IPTV service in production, if you want to avoid spending days of troubleshooting directly with your customers.
As it goes for the IP core network, you need to define how to route the multicast traffic. It is good practise to separate multicast VLAN in the core and toward end users. There are several methods for multicast routing you can use. Most commonly used is the PIM which is supported by majority of core IP routers. Similarly, you also need to define organization of access network, whether to use VLAN per user or VLAN per service, being two most commonly used approaches.
What to measure?
Based on all so far written, you should be able to define several assessment points in your network and start measuring. The most important parameters for IPTV that you need to measure are jitter, network delay, available throughput and packet loss. Make sure that your measurement is done on all types of network equipment used and all regions you plan to use your service. In addition, measurement should be organized to cover both end to end delivery of the service and delivery of the service on all used network paths.
“It is also very useful if you can connect one real multicast stream and few test STB devices and test the video streaming quality over time.”
It is also very useful if you can connect one real multicast stream and few test STB devices and test the video streaming quality over time. Beside monitoring video quality on the TV screen, check also STB logs for some video receiving or decoding errors and compare the results with the DSL lines monitoring tool. This will give you good insight view on the video streaming capability of your network.
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I hope, you will find this blog useful and it will help you in defining your IP network to be ready for the IPTV service. In case you will need some additional information, guidance in performing the measurements or to get second opinion on your network design, don’t hesitate to contact me. We look forward to help you.
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