Cisco ASR 5000 series Product Overview page 226

▀ Introduction
Step Description
4 Upon receipt of the R4 LU_Req message, a relay PC ASN adds the anchor PC Relocation Destination TLV to initiate PC
relocation. The message is forwarded to the anchor PC ASN. The new anchor PC ASN starts timer TR4_LU_Request.
5 If the current anchor PC ASN retains context information for the MS, including its authenticator ID, the current anchor PC
ASN initiates a Context Request procedure with the anchor authenticator ASN. If the anchor authenticator ASN has valid
key material for the MS, it returns AK context for the MS to the anchor PC ASN.
6 The current anchor PC ASN sends an R4 LU_Rsp message back to the new anchor PC ASN and starts timer
TR4_LU_Conf. The message includes the MSID, BSID, authenticator ID, assigned PGID, Paging Offset, Paging Cycle,
Anchor PC ID TLVs, and Location Update Status TLV set to Accept. The anchor PC Relocation Request Response TLV is
set to Accept to indicate that the current anchor PC ASN accepted the PC_Relocation_Req and the anchor PC ID TLV is
set to the identifier of the new anchor PC ASN ID which was received in the anchor PC Relocation Destination TLV in the
R4 LU_Req message. The R4 LU_Rsp message also includes MS Info TLV containing the MS context for transfer to the
new anchor PC ASN. If the new anchor PC ASN does not request PC Relocation, the current anchor PC MAY still request
to perform the procedure by including the PC Relocation Indication TLV. If the new anchor PC does not accept the
relocation, it reports a failure in step 17.
7 Upon receipt of the R4 LU_Rsp message from current anchor PC ASN, the new anchor PC ASN stops timer
TR4_LU_Req, stores the MS context received from current anchor PC ASN, updates the paging information (Paging
Group ID, Paging Cycle, Paging Offset), forwards the R4 LU_Rsp message on to the serving ASN, and starts timer
TR4_LU_Conf.
8 Upon receipt of the R4 LU_Rsp message, the serving ASN-GW stops timer TR4_LU_Req, sends an R6 LU_Rsp message
to the S-BS, and starts timer TR6_LU_Conf. The message includes the Location Update Status TLV set to Accept, MS
Info, AK Context, anchor PC ID, and the old anchor PC ID TLV. The message may include the paging information TLVs
if they were included in the corresponding R4 message.
9 Based on the AK and AK context received from the current anchor PC, the serving BS (associated with local PC/relay PC)
successfully authenticates the RNG_REQ message received from the MS. The serving BS sends a RNG_RSP message with
HMAC/CMAC and Successful Location Update Response indication to the MS.
10 The serving BS sends an R6 LU_Cnf message to the serving ASN-GW with Location Update TLV indicating success.
Upon receipt of the message, the serving ASN-GW stops timer TR6_LU_Conf.
11 The serving ASN sends an R4 LU_Cnf message with a successful LU indication to new anchor PC ASN (as indicated by
the anchor PC ID received from the BS) and stops timer TR6_LU_Req. Alternatively, the relay PC ASN forwards LU_Cnf
to the ASN associated with new anchor PC with the result indication reassigned by the relay PC. Upon receipt of the
message, new anchor PC ASN stops timer TR4_LU_Conf.
12 Upon receipt of the LU_Cnf message, the new anchor PC ASN sends an R4 PC_Relocation_Ind to the anchor DP/FA ASN,
and starts timer TR4_PC_Reloc_Upd_ADP.
13 The anchor DP/FA ASN updates the anchor PC for the MS with the new anchor PC ASN ID and responds with an R4
PC_Relocation_Ack message confirming the anchor PC update. Upon receipt of the message, the new anchor PC ASN
stops timer TR4_PC_Reloc_Upd_ADP. The new anchor PC ASN hosts the anchor PC function and becomes the new
current anchor PC ASN for the MS. The anchor PC is de-allocated from the old current anchor PC ASN.
14 Simultaneous with sending PC_Relocation_Ind to the anchor DP/FA, the new anchor PC sends an R4 PC Relocation
Indication to the anchor authenticator ASN to inform the change of the anchor PC, and starts timer TR4-
PC_Reloc_Upd_AA.
15 The anchor authenticator ASN updates the anchor PC for the MS with the new anchor PC ASN ID and responds with an R4
PC_Relocation_Ack message confirming the anchor PC update. Upon receipt of the message, the new anchor PC ASN
stops timer TR4-PC_Reloc_Upd_AA. At this point, new anchor PC ASN hosts the anchor PC function and becomes the
new current Anchor PC ASN for the MS. The anchor PC is de-allocated from the old current anchor PC ASN.
▄ Cisco ASR 5000 Series Product Overview
ASN Paging Controller and Location Registry Overview
OL-22938-02