Cross Connect for Iu-PS Interface of UMG 8900

Definition

In traditional networks, the media gateway (MGW), radio network controller (RNC), and serving GPRS support node (SGSN) are physically connected. The RNC communicates with the SGSN over the Iu-PS interface. When there is less GPRS traffic over the Iu-PS interface, this physical connection is not fully utilized.

The cross connect for Iu-PS interface feature enables the MGW to transfer IP over ATM packets between IP networks and ATM networks. It eliminates the need for the physical connection between the RNC and the SGSN.

Benefits

Application Scenario

This feature is used when the following two conditions are met:

• Only the IP over ATM packets are used between the RNC and the SGSN.
• The RNC or SGSN uses ATM bearer, and the peer end uses IP bearer.

Figure 1 shows the networking for this feature.

Figure 1 Networking for the cross connect for Iu-PS interface feature 

Implementation Principle

Data Processing Inside the MGW

• Upon receiving ATM packets sent from the RNC, the rear boards of the ATM service processing units (ASUs) send the packets to the ASUs. The ASUs transparently transfer the packets to the high-speed routing boards (HRBs), which then transparently transfer the packets to the SGSN through the rear boards.
• Upon receiving the IP packets sent from the SGSN, the rear boards of the HRBs send the packets to the HRBs. The HRBs transparently transfer the packets to the ASUs, which then transparently transfer the packets to the RNC through the rear boards