Cisco Cisco ASR 5000
RIM Message Transfer from BSC or RNC to eNodeB
▀ How It Works
▄ SGSN Administration Guide, StarOS Release 18
4. On invocation of this API the GTP module will encode the RAN info relay message (as per TS 29.060) and
dispatch the PDU to the peer MME.
Call Flows - Receiver of GTP RIM Msg
The following call flow illustrates how the SGSN behaves as the receiver of GTP RIM messages.
Figure 78. Receiving a GTP RIM Message
In this case, the SGSN has to decode the incoming GTP message correctly and forward the RIM message to the
destination RNC/BSS.
destination RNC/BSS.
1. SGSN would decode the received GTP RAN info relay message and construct a RANAP or BSSGP RIM
message.
2. Appropriate actions would be taken to forward the RIM message to the destination RNC/BSS.
RIM Application
The RIM application processes the decoded RIM PDU from the access application. The routing area identifier (RAI) --
comprised of the mcc, mnc, rac -- is extracted from the destination address and is used to decide if the target routing
area (RA) is local. If the RAI is locally available, the PDU is forwarded to either the RANAP or BSSGP stack based on
the RIM routing address discriminator field.
comprised of the mcc, mnc, rac -- is extracted from the destination address and is used to decide if the target routing
area (RA) is local. If the RAI is locally available, the PDU is forwarded to either the RANAP or BSSGP stack based on
the RIM routing address discriminator field.
The SGSN has a global list of local RAs. Each RA in turn has a list of RNCs and NSEIs that control it. If the destination
RA is local, the list of NSEIs which serve the RAI is fetched. Each NSEI is searched for a matching cell id in the cellid-
list. The PDU is then forwarded to the NSEI when signaling the BVCI.
RA is local, the list of NSEIs which serve the RAI is fetched. Each NSEI is searched for a matching cell id in the cellid-
list. The PDU is then forwarded to the NSEI when signaling the BVCI.
If the RNC Id is in the destination cell identifier, then the IuPS service serving the local RAI is identified. The PDU is
encoded in a RIM container and forwarded to the corresponding RANAP stack instance of that IuPS service.
encoded in a RIM container and forwarded to the corresponding RANAP stack instance of that IuPS service.
If the eNodeB Id is in the destination cell identifier, then the PDU will be sent to the GTP app using the appropriate
event.
event.
The peer-MME address is resolved using the SGSN's local configuration or a DNS query for the TAI present in the
destination address. For a successful DNS response, the PDU is encoded in a GTP RIM container and forwarded to the
peer-MME. The SGTP service used will be the default SGTP service associated with the GPRS service or the SGSN
destination address. For a successful DNS response, the PDU is encoded in a GTP RIM container and forwarded to the
peer-MME. The SGTP service used will be the default SGTP service associated with the GPRS service or the SGSN