Cross Connect for Iu-PS Interface

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 the general packet radio service (GPRS) traffic over the Iu-PS interface is light, the physical connection between the RNC and the SGSN is less utilized. Cross connect for Iu-PS interface enables the MGW to transfer the Internet Protocol (IP) over asynchronous transfer mode (ATM) packets across the ATM network and the IP network. In this way, the signaling and service traffic between the RNC and the SGSN can be forwarded by the MGW, and the physical connection between the RNC and the SGSN is not required.

Application Limitations

The RNC must be able to process IP addresses and send and receive the IP over ATM packets.

Application Scenario

Figure 1 Application scenario for this feature
http://localhost:7890/pages/31185046/01/31185046/01/resources/figure/fig_cn_10_02_0030301.png

Implementation:

Iu-PS Interface Transfer (Inside MGW)

• Upon receiving the ATM packets sent from the RNC to the SGSN, 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 to the RNC, 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.