Dear Experts.
Please, in which L3 signaling message can we check the request of UE for IP Class: IPV4 or IPV6 for 4G network and 5G network?
Check for PDUSessionResourceSetupRequest.
Thanks!
Please and for VoLTE session establishment?
I am talking about session with IMS…
UE sends PDN Connectivity request again for Lte network connection, PDN Type can be seen as IPV4 and IPV6, and it is of great importance that both IP types, especially IPV6, are supported. VOLTE UE must support IPV6.
The APN name is seen as IMS and this is a universal value. Even if the UE requests any APN name, it assigns this name by default:
Configuration protocols are seen in the PDN Connectivity Request, from 1 to 5, each of them has a different meaning, and since the request has just come from the UE and the UE does not know some parameter values, the contents values are always seen as zero because the NW has not responded to the UE yet:
Activate_Default_EPS_Bearer_Context_Request contains PDN type information (IPV6) and IP address information allocated to the Member.
The “selected bearer control mode” parameter is basically used by the network to tell the UE whether bearer creation and switching can be triggered by the UE alone or whether both the UE and the network can trigger bearer creation and switching together:
It contains UE IP information and TCP/UDP port information, as can be seen in the messaging highlighted in blue.
There is also a URL address to which the UE will connect, and this URL address contains UE IP information and domain information.
There are two different information in the callID section. It includes the call ID part sent by the UE and defined by the NW + UE ip address information:
Thanks for these precious informations! 
Hi, thanks for great info!
Do you have any examples for multiple Ipv6 assignment per UE?
Prefix delegation for CPE, etc?
Multiple IPv6!
Interesting.
Usualling there is one IP per APN type.
So a default bearer and IMS are 2 separate IPs.
If you add another APN, that will be a different IP address.
Potentially all can be IPv6.
What I mean is a scenario where we have a CPE with 6 users behind it.
Each of these 6 users can have their seperate global uniqe IPv6, hence their own Qos.
So one flow for each UE behind CPE.
Am I correct or I am getting it wrong?
That concept is routing behind MS and even if you assign unique IPv6 to them, they can’t have their own QoS as all of them are behind of one MS, which has only one bearer and QoS.
CPE is seen by network as a single user.
CPE is a router and not a repeater, meaning it doesn’t create a local 3gpp 5G/LTE network.
It provides LAN/WLAN/IpPHONE connectivity locally.
So UEs behind CPE just access WiFi or VoWifi.
What if we consider it as a V2X 5G modem with several interfaces?
So no wifi and Vowifi behind it. Just direct feeding of several IPv6 addresses to the modem.
I think we can assign for example 3 seperate Ip prefixes to one modem and all of them within a PDU session.
Then SMF would diffrentiate them based on IPv6 header flow lable/traffic class.
Interesting use case…
I think the V2X modem’s primary purpose is to communicate with external infrastructure via cellular networks/ITS band and interfacing with digital systems within veghicle.
It does not create localized cellular or WiFi networks within the vehicle.
So, in context CPE and UEs, that’s not possible here as well.
I am still reading on this topic and found some interesting docs.
One of them recommends:
Advertising Multiple Prefixes
In order to allow for the configuration and use of multiple IPv6 addresses per primary PDP Context having different interface
identifiers, some modifications to the current 3GPP specifications
would be required.
NOte that the recommended solution does not imply or assume that the
mobile device is a router. The MT is expected to use the /64 for itself and may also use this prefix for devices attached to it.
However, this is not necessary if each device behind the MT is connected to a separate primary PDP Context and therefore can use a/64, which is not shared with other devices.
https://www.rfc-editor.org/rfc/rfc3314#page-14
Will add more details after I found out exactly how we can use more than one global uniqe IPv6 address on a UE.