Brief Description.

A circuit identification code (CIC) uniquely identifies a circuit between two signaling points. In the networking where time division multiplex (TDM) is used for connecting to the UMG8900, the UMG8900 reports the number of available CICs to the mobile switching center (MSC) server. Such CIC information is essential for the MSC server to select UMG8900s and to determine whether to bar a call.

CIC in an IP Scenario:

In an MSC pool, MSC servers share all IP-based A interfaces or Iu interfaces. The base station controller (BSC) or the radio network controller (RNC) connects to the UMG8900 through Internet protocol (IP) or asynchronous transfer mode (ATM). That is, traffic heaviness is determined based on bandwidth usage but not CIC availability. To address such a change, virtual circuits and virtual CICs are introduced. By making calculations based on actual bandwidth usage, the UMG8900 obtains the number of available virtual circuits and reports their virtual CICs to MSC servers.

The number of virtual circuits indicates the number of available virtual channels between the UMG8900 and the BSC or the RNC. Therefore, the number of virtual circuits is described as the number of available virtual channels.

Limitations:

• This feature is not applicable on an IP-based network or ATM-based network through which an RNC connects to the UMG8900.
• Resources that keep being used before and after this feature is enabled are not counted as occupied virtual channels.
• You are advised to enable this feature at night when less than 100 subscribers are connected to the UMG8900.

The IP CIC flow is as follows:

1. HRB periodically reports IP bandwidths occupied for each BSC or RNC to the OMU.
2. ASU periodically reports ATM bandwidths occupied for each RNC to OMU.
3. Upon receiving the bandwidth data, OMU calculates the number of available virtual channels and sends the result to HRB. OMU also periodically reports the result to CMU. By default, OMU reports the result per 30 seconds. The interval can be adjusted by setting P68.
4. Upon receiving the number of available virtual channels, CMU sends an H.248 message to the MSC server. Such CIC information is essential for the MSC server to select UMG8900s and to determine whether to bar a call.

For more details refer to this topic on UMG8900 product documentation.