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Dedicated bearer creation QOS relates?

+1 vote

As of now the basic setup for the dedicated bearer works ok (with and without Diameter interface)

As of now, for this initial work, I am trying to see if this can be extended now..Now PCRF just accepts the QCI requested.

Lets say we want to create a new dedicated bearer, then PCRF gets a request saying it needs to create a ded bearer with QOS( QCI=3, Max GBR Ul =10Mbps, MaxGBR Dl=10Mbps, GBR Ul = 5Mbps, GBR Dl=5Mbps.
Lets say this user is assigned, MaxGBRUl =5, MaxGBR Dl=5Mbps, GBR Ul = 2.5Mbps, GBR Dl=2.5Mbps.

What should pcrf do this case ? Allow to create the ded bearer with MaxGBRUl =5, MaxGBR Dl=5Mbps, GBR Ul = 2.5Mbps, GBR Dl=2.5Mbps. ? Or decline to create it ?

Your inputs much appreciated...

posted Oct 19, 2015 by Pdk

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5 Answers

+1 vote
Best answer

You can do it based on the subscription of the subscriber. You can simply define a policy where if the category is let's say Gold give bandwidth of 5Mbps and for silver give 3Mbps and likewise

answer Oct 21, 2015 by Peeyush Sharma
Lets say the subscriber is gold (given BW 5Mbps)...Now when he creates 1st ded bearer with GBR=5Mbps. Can he create a second bearer again with 5Mbps ?
My Question is, whether this(QOS) will be monitored somewhere else to check the total GBR doesnot exceed the one subscribed ?
Because while googling i had found we can directly assign the GBR based on subscription option which is confusing..I was thinking whether there is a way to limit the total BW for all GBR bearers depending on some subscription option
+2 votes

If I interpreted your query correctly, please find my following comment :
--> PCRF node can modify UE requested QoS parameters and network responds to UE with the modified QoS parameters.
These modified QoS parameters will be sent to UE by using the NAS message i.e. "Activate Dedicated EPS bearer context request" message.

answer Oct 19, 2015 by Harshita
Thanks Harshita for the reply and answer.

But could you let me know, how exactly is the QCI is reallocated based on what parameters ? (It wil be nice if you do this by giving some numbers for QOS params like QCI, MBR, GBR etc)
Could any experts on Gx help with this please ?
+2 votes

Based on the subscription of the user PCRF can upgrade or downgrade the QoS values for the one requested by UE.

Like in case of your example PCRF is downgrading the qos parameters. It has the authority to do so.

Peeyush Sharma

answer Oct 20, 2015 by Peeyush Sharma
Thanks a lot Peeyush .

Currently in basic implementation, when CCR(initial) comes with default EPS bearer info. PCrf can select the QCI based on this or apn.

Later for dedicated bearer setup , just to verify diameter, i am just using whatever QOS requested. But we may need to check the subscription option. Not sure what parameters to use ?

But what I am after actual algo pcrf can implement. It is whether to assign a kind of subscription options like bronze, silver or gold to each user and let a datarate for the user depending on subscription option.

I think in our current HLR we have the AMBR-UL and AMBR-DL for the susbscriber. So I think this applies to nonGBR bearers. When a new NonGBR bearer is requested to be setup by PCRF, which parameters are to be changed etc ?

Whatabout for GBR type of dedicated bearers ? What algo can be applied to get the actual values.

I am looking for basic implentation to check QOS for GBR and non GBR bearers
+1 vote

Usually if a dedicated bearer is created from a N/W side then all the info comes from P-CSCF. On top of it some policy definition can be done based on the subscription.

If a request comes from UE side then usually you get the necessary parameters from the request itself. However in case of non-gbr bearer requested from UE side the mbr parameters have to be defined by PCRF and can be defined based on QCI or maybe subscription

Based on the subscription like in your example Gold, Silver, Bronze depending on service you can define some qos parameters in PCRF policy definition that can be used.

Peeyush Sharma

answer Oct 21, 2015 by Peeyush Sharma
Peeyush thanks a lot for your willingness to help with your indepth knowledge on this field. Much appreciated.

Lets just look at GBR bearers just make myself not get confused :) . If requested by  P-CSCF or UE side, PCRF receive the requested QOS. So PCRF can use the same. But then why a subscriber is allocated Gold, Silver, Bronze ? If allocated what can be the basic policy ?

I am sorry for the basic question, but want to implement someway to limit to total GBR even when requested by PCSCF or UE.
Can you please frame your queries into separate points. Even I need to dig deep into the subject to find answers for the category questions

Please make a list of collective doubts and mark it into different points, so that we can cover all the aspects of qos authorization.

Peeyush Sharma
Sorry for confusion and so many queries
I will just restrict my query to GBR bearers in this thread, and rise a new question for nonGBR,

-Regarding GBR bearers:
In a simple implementation, lets say there are three types of subscription{bronze(GBR=3,MBR=3), silver(GBR=5,MBR=5) and gold(GBR=10, MBR=10) }.A subscriber is assigned Gold subscription which is GBR=10Mbps, MBR=10Mbaps
1) Now my question is, if he gets a request for two dedicated bearers each with GBR =10Mbps,(MBR=10Mbps) what happens . Service type lets say video for both bearers
2) Request for 1st dedicated bearer GBR=10Mbps (MBR=10Mbps) and second with GBR=5Mbps (MBR=5Mbps) . Even here both are "video" media type

Can PCRF assign the subscribed BW (if the requested is greater) and forget for each bearer and think that either UE/ENB takes care of total GBR for all dedicated bearers for that particular user dynamically.

i.e In case 1, assign 10Mbps for both dedicated bearers.
Also can you specify what will be the service used for the dedicated bearer

In case a request comes from PCSCF it usually have the service information like if it would be voice video sms etc.
+1 vote

I will give try to answer the question in some time. Gimme an hour or 2

answer Oct 21, 2015 by Peeyush Sharma
Np Peeyush, you can take your time..No hurry..But your inputs are much appreciated
May be I was wrong in interpretting the spec.

I think the GBR and MBR are provided by the subscription for each user for particular service type. When that type of service is added, the subscriber profile for that service type is checked. If there is a GBR and MBR associated it will be used.I think the subscriber profile will be updated for particular GBR and MBR based on the whether he is "broze", "silver" or "gold" upon subscription. So Pcrf, just picks this info..It is upto enodeb and PGW to check the total BW is not exceeded for APN and UE.. Hope my assumption is correct, otherwise please feel free to correct me..
Usually what will happen is that in SPR there would be categories defined like Gold, Silver and Bronze and for every service there will be some bandwidth configured for each category.
Let's say there are 3 subscriber and 1st one have Gold 2nd have silver and 3rd have bronze category subscription.
For voice service there would be a service configured S1.
So, let say from PCSCF a request some with some bandwidth let's say 3 Mbps
What PCRF can do is that it can check the subscription of the subscriber.
For Gold let's say it is configured that S1 service will get 10Mbps bandwidth and for Silver it is 5Mbps and for Bronze it is 2Mbps.
So for Gold subscriber PCRF can send RAR with GBR values 10Mbps by upgrading the one which was requested i.e. 3Mbps
For Silver also it can upgrade the bandwidth to 5Mbps.
However for bronze it might reduce it to 2Mbps.

Peeyush Sharma

Thanks a lot Peeyush.
Similar Questions
+2 votes


Pardon me, this is just a theoretical question. Not started my real testing yet. But so meantime trying to see I handle the basic possible scenarios.

In the CCR message of type (Initial Request), lets say PCRF receives both the "QOS" (containing APN AMBR UL and APN AMBR DL) and "Default Bearer QOS" AVP (containing QCI and ARP).
As of now, in my basic code, I return the QOS based on apn info received on "Called-station-ID" AVP. Will it be ok..Or is there any better suggestions on this ?


+1 vote

Hello all,

Can anybody suggests how we can set maximum bitrates for parameters like MBR, GBR (UL,DL), APN-AMBR(UL/DL), UE-AMBR(UL/DL) for GBR and Non GBR bearer.?

Are those values standard from PCRFor does it define dynamically based on user subscription.?
Please suggest some sources to choose the exact the bitrates for QoS parameters mentioned above.

Thanks in advance,

+1 vote
  • As per Policy Control and Charging, we can have multiple rules i.e. rule-group mapped to one pcc-action.
  • One pcc-action should have a specific rating-group Id and service-Id and Qos.
  • Since, a dedicated bearer has a fixed Qos, we can say that dedicated bearer is associated with only one pcc-action.
  • According to Gx Spec 29.212, when Rule-Definition is received from PCRF, it comes with rating-group-id, Qos, and Flow-Information to create a dedicated bearer.

So, is it possible that PCRF can send two different rules say RD1 and RD2 with same Qos but different rating-group-id. I dont see this thing mentioned anywhere in 29.212.

Please help with reference to spec...

+3 votes

Lets say we have a session-0 established for the UE (IPaddress1) for the default bearer. This is when the PGW send the CCRequest(cctype=initial and ccnum=0). Lets say "Policy1" is sent by PCRF in CCA. Does this initial CCRequest has the "Flowdescription" AVP in this ?

Now a dedicated bearer1 is established so CCRequest is sent with (ccrtype =modify and ccnum=1). Lets say PCRF assigns "Policy 2".

Now dedicated bearer 1 is deleted, then what does the PGW send to PCRF ?

Another question: As of now I am storing the list of PolicyRules in PCRF, based on IMSI (IPAddress)..i.e c++ map of IPAddress and PolicyRules. But when the dedicated bearer is removed how do i access the map ? (to find which Policy is deleted)

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