top button
Flag Notify
    Connect to us
      Facebook Login
      Site Registration Why to Join

Facebook Login
Site Registration

What is the difference between Gx and Gz?

+5 votes

What is the difference between Gx and Gz interface.
As we know the interface between P-GW and OFCS is Gz interface and P-GW to PCRF is Gx.
Why both the interfaces are considered as Offline Charging

posted Dec 27, 2015 by Chinmoy Padhi

Share this question
Facebook Share Button Twitter Share Button LinkedIn Share Button

2 Answers

+1 vote

Chinmoy, as far as I know, interface is between PECF and PCRF is known as Gx and it is used to policy and charging rules exchanges between these two nodes. This interface as such is not used for charging purpose.

CDRs generated by PGW are sent to OFCS by using the Gz interface.

answer Dec 27, 2015 by Vimal Kumar Mishra
+1 vote

Gx and Gy are different Diameter "Applications". Their PDUs different. Though they use the same Diameter commands (CCR/CCA, RAR/RAA), similarity ends there.
Gx is used for policy control. PCEF sends request for Policies and PCRF responds with Policies.

Gy is used for billing and related authorization etc. PCEF or some other function sends the subscriber information and Onile Charging System responds with authorization (for the usage of resources) and any additional information like how long the service can be consumed, when to report back etc.

So, apart from the fact that they are Diameter extensions (and thus connection setup, request forwarding, session management etc are done in the same way), they don't have much in common. Of course, they have many AVPs in common.

answer Dec 28, 2015 by Rathnakumar Kayyar
Hi Rathnakumar,
Thanks for the information.Could you please edit your answer,my question is regarding Gz and Gx interface, the above explanation gives the difference about Gy and Gx interface.
Sorry that I spoke about Gy instead of Gz, but the answer is the same. Except that Gz is used for Offline Charging (Gy is used for Online Charging). Gz uses different commands (ACR/ACA) and is session less. But the key point is, these are different protocols (or applications) serving different purposes.
Thanks Chinmoy and others for these discussions..
Btw, just to add to this discussions, it would be helpful, if somebody explains me how to correlate the initial Gx (CCA) , basically the charging information, with the Gy/Gz AVPS..Sorry for jumping into this thread, but i felt this is related to this q. @Chinmoy, if this not ok, i can start a new thread (if this is diverting your query)
Hi Rathnakumar,
Could you please suggest which 3GPP spec is used for Gz Interface
32.299 - this is the starting point. It further refers to "domain specific" documents.
Similar Questions
+12 votes

Why do we require Gate Function ? I mean to say what is the need for this ? How Significant it is in Gx-Interface?

+1 vote

Is it possible to use Credit-Control-Failure-Handling AVP in Gx interface. If so, how?

My query is when PCEF sends a CCRequest to PCRF and PCRF does not reply anything, so in that case will that be possible to use Credit-Control-Failure-Handling(CCFH) avp.

Does this behavior allowed as per 3GPP Standards or its upto the customization of the product. Any reference are highly appreciable.

+2 votes

How PCEF decide which QCI_X(where X = 1,2,3,4,5,6,7,8,9,65,66,67,68,69,70) value need to be send to PCRF.
What is the significance of so many QOS-Class-Identifiers?
Even 3GPP 29.212 doesn't define any reason for classification between different QOS-Class-Identifiers.

0 votes

When we talk about CDR (charging data record) in LTE or any other technology, following questions come in my mind.
- Is CDR generated per UE ? or Is per session per UE or generated for group of UEs ?
- What information is captured in CDR ? Does 3GPP define any standard format and IEs that need to be captured or is it completely operator dependent ?

Contact Us
+91 9880187415
#280, 3rd floor, 5th Main
6th Sector, HSR Layout
Karnataka INDIA.