PDD of Post Dial Delay For VoIP – Meaning, Reasons, Solutions

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pdd - post dial delay - asr

Today we will talk about one of the most important issues of VoIP, PDD, in other words Post Dial Delay. PDD is one of the main reasons for other rates in a traffic. PDD may appear as a result in some cases or maybe the reason itself. Let’s start to explain our topic.

What is the meaning of Post Dial Delay, PDD?

Post Dial Delay is the average time before hearing the ringtone. 

What are the consequences of high PDD rates?

High PDD values are the main reasons for the low Average Success Rate, ASR. People don’t want to wait too long before hearing the ringtone, and they close the phone when it’s not connected. This will cause to miss calls. When the caller closes, call ends and there will be no re-route. 

What are the main reasons for getting high PDD rates?

There are several reasons for receiving high Post Dial Delay. If you are seeing high PDD values in traffic, you should focus on those things to solve the problem.

  • Destination based 
  • Exceeded HOP
  • Provider 
  • NCLI

Destination Based

Some destinations have standard PDD profiles. For example this rate is between 8 to 9 seconds for Syria, but it is around 3 to 4 seconds for Turkmenistan. This rate can change according to the traffic profile. We need to test these destinations’ traffic profiles by sending them to the direct route. After all, if there are higher values than the average, we can understand that there is a problem with the provider.

Exceeded Hop

There is a big PDD difference between sending the traffic directly and and sending them through 6-7 different vendors. Because high delay times and package loses are very normal when you sending the traffic over many different servers. 

Provider Problem

There can be a problem with the carrier service internet and because of this, delay times can be high with the provider. It’s also possible to be NCLI.

NCLI Problem

Some NCLI routes can use low speed home internet connection so it takes too much to open packages and this will cause high delay times. Providers can use fake RBT and fake RBT will help to decrease PDD rates. But ASR rates still will be low because people will hear the fake ringtone and still wait for too much and think that the person is busy to open the phone. Eventually they will give up on calling.

If you want to learn more about VoIP or need the best quality VoIP provider, you can feel free to ask anything about this sector to us. 

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