With the development of 4G networks, UE IP address conflicts become more and more serious.

1. This increases the types of external interface sessions for the Unified Policy and Charging Controller (UPCC). For example, there are single sessions over the Gx, Rx, Gxx, Sd, and Sy interfaces in the 3GPP PCC architecture. Then multiple sessions over the Gx and Rx interfaces are supported, and finally multiple PCEF sessions are introduced in mutiple PCEF scenarios. The UPCC must provide binding management for all types of sessions for each subscriber to implement session policy association.

 

2. The PCRF does not exist in earlier networks. In this scenario, each GGSN only has to ensure that it has assigned a unique IP address for each subscriber. It does not need to check for IP address conflicts between different GGSNs. However, after the PCRF is introduced and the GGSN is connected to the PCRF, IP address conflicts must be considered. This conflict becomes more significant when IPv4 addresses are gradually exhausted.

To solve this problem, the UPCC must properly and systematically distribute, bind, and manage all types of sessions for each subscriber.  And from now on, we will continue to release more posts to show you how to solve these problems regarding to the IP address conflicts.

Function of MS/UE IP addresses

An MS/UE must obtain an IP address before using data services. An MS/UE IP address uniquely identifies a PDN connection for an MS/UE. In other words, an MS/UE can establish multiple PDN connections at the same time and each PDN connection has a unique IP address.

Generation of MS/UE IP addresses

When establishing the default PDN bearer, an MS/UE carries the PDN Address Allocation AVP. This AVP contains the address type and an IP address (a static IP address or the IP address 0.0.0.0 for a dynamic address) for the MS/UE to access an external PDN. On an EPC network, the MS/UE informs the EPC network the IPv4 or IPv6 address assignment mode that it expects to use to obtain an IP address.

When establishing the default PDN bearer, the Huawei P-GW provides the following IPv4 or IPv6 address assignment modes:

• Static IP address assignment

  An IP address is assigned to an MS/UE when the MS/UE subscribes to a packet service on the home location register (HLR) or home subscriber server (HSS). This IP address is carried in an AVP in PDP context or bearer activation request messages and sent to the P-GW. This mode is applicable when static IP addresses are required for MSs/UEs.

• Local IP address pool assignment

  An IP address from the address pool configured on the P-GW is dynamically assigned to an MS/UE during PDP context or bearer activation. This mode is applicable when carriers do not want to deploy a device used to assign IP addresses to MSs/UEs, reducing operating costs. This mode is commonly adopted on existing networks.

  On the Huawei P-GW, the local address pool is bound to the APN to dynamically assign IP addresses. A maximum of 16 address pools can be bound to each APN. Address pools configured on the P-GW are composed of available address sections that are planned by a carrier.

   NOTE:

  The local IPv4 address pool does not assign addresses whose host IDs are all 0s or all 1s to MS/UEs.

• RADIUS IP address assignment

  In this mode, an MS/UE is dynamically assigned an IP address from the RADIUS server during MS/UE authentication in PDP context or bearer activation. This mode is applicable when intranets or Internet service providers (ISPs) have RADIUS servers.

  The Huawei P-GW supports IP address assignment by the RADIUS server during MS/UE authentication on the RADIUS server. Addresses are carried in access responses returned by the RADIUS server.

Thanks good info 4g core

Thanks for sharing @Tony.Cheng

@Atif @Shupak @Babar.Bash @Arian @maverick @Xubare

Good doc then what the maximum number of ue when use ipv4?

sohaib_alhilf 发表于 2016-09-28 05:12 Good doc then what the maximum number of ue when use ipv4?

The maximum number of UEs depends on the size of the address pool of the PCEF that generates IPv4 addresses as well as the maximum number of IP addresses represented by the IPv4 segment.

If I have two group given individual IP range but one of ue should connected with these two group how I could solve this case could I give one UE two IP each one used with one apn ( pool ip)

sohaib_alhilf 发表于 2016-09-28 19:15 If I have two group given individual IP range but one of ue should connected with these two group ho ...

Hello!Do you say the two IP segment range refers to the PCEF pool of the IP range?

yea

Posted by carryout at 2016-09-28 17:16 Hello!Do you say the two IP segment range refers to the PCEF pool of the IP range?

Yes but one UE connect with to group what should I do give it two IP

sohaib_alhilf 发表于 2016-09-29 04:12 Yes but one UE connect with to group what should I do give it two IP

Hello!I think it's possible.
A UE can be connected to different APN through different PCEF, and then access to different PDN .
Two PDN, each assigned their own IP .