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Control Plane RoamingLBS Roaming Meeting, Denver
January 18, 2007
Control Plane RoamingLBS Roaming Meeting, Denver
January 18, 2007
Page 2Control Plane Roaming Update
• A few CP deployments out there, with a few more on the way
• Growing number of Control Plane enabled mobiles
• Control Plane roaming is important and seems straightforward
• It was agreed at previous LBS Roaming Summits that an RLP variant would be used as the protocol between Control Plane MPCs as opposed to IS-41 based ISPOSREQ / isposreq as defined in IS-881
• Openwave has defined such a variant and is in the process of releasing the spec to the CDG IRT and this group
• A review of the Openwave spec is required and potential enhancements and standardization efforts need to be considered
• The RSP / CRX issues (no access to true serving system information) still need to be resolved
Page 3IS-881 Roaming Call Flow
LCS Client
MS
MLP SLIR (MDN,…)
LPREQ (MPCID, MDN,…)
IS-801 exchange
GPOSREQ (MSID, MPCAP, ServingCellID,...)
gposreq (POSINFO)
H-MPC
S-PDE
S-MSC
a
c
b
d
e
f
g
h
i
j
HLR
k
l
S-MPC
lpreq (MSID, MPCAddr (serving), MSCID (serving), MPCAP…)
ISPOSREQ (MSID, MSCID (serving),…)
ISPOSREQ (MSID,…)
Paging / Traffic Channel
Assignmentisposreq (MPCAP, MSCID, ServingCelID, MOBINFO,…)
isposreq (POSINFO,…)
MLP SLIA (POSINFO,…)
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Expected Control Plane Roaming Architecture
RSP RSP
Home Operator Visited Operator
MSC/VLR
H-MPC
HLR
IS-41 Signaling
HLR
H-MPC
V-MPC
IP Network (L3)
IP Network (L3)
V-PDELCS Client
IP Traffic
Page 5RSP Issue
• Most operators prefer to use RSP for roaming
• RSP provide peering point for SS7/IS-41 exchange between operators
• RSP provides intermediary HLR function
• During registration, home operator receives generic MSCID provided by RSP
• Home operator won’t be able to map generic MSCID to correct V-MPC for L3 interface
• Also the message used on the L3 interface to invoke the V-MPC needs to pass the serving MSCID to allow the V-MPC to execute local IS-881 procedures (e.g., invoke the serving MSC)
Page 6RSP Issue Illustrated
• MS registers and RSP replaces MSC/VLR MSCID with generic RSP MSCID• LCS Client queries H-MPC for roaming MS• H-MPC uses LOCREQ/SMSREQ to receive MSCID (RSP HLR) from HLR• H-MPC needs to map MSCID (RSP HLR) to the IP address of V-MPC• Because MSCID is generic RSP MSCID, the H-MPC doesn’t know where the V-MPC is
RSP RSP
Home Operator Visited Operator
MSC/VLR
H-MPC
HLR
IS-41 Signaling
HLR
H-MPC
V-MPC
IP Network (L3)
IP Network (L3)
V-PDELCS Client
IP Traffic
MSCID = RSP HLR
MSCID = RSP HLR
MSCID = MSC/VLR
RSP HLR = ?
Page 7RSP Issue Solution #1
• MS Registers and RSP provides the serving MSCID to home operator• LCS Client queries H-MPC for roaming MS• H-MPC uses LOCREQ/SMSREQ to receive serving MSCID from HLR• H-MPC maps serving MSCID to the IP address of V-MPC• H-MPC performs L3 transaction with V-MPC (passing serving MSCID)
RSP RSP
Home Operator Visited Operator
MSC/VLR
H-MPC
HLR
IS-41 Signaling
HLR
H-MPC
V-MPC
IP Network (L3)
IP Network (L3)
V-PDELCS Client
IP Traffic
MSCID = MSC/VLR
MSCID = MSC/VLR
MSCID = MSC/VLR
Visited Op = 127.4.64.1 127.4.64.1
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IP Network (L3)
IP Network (L3)
RSP Issue Solution #2
• MS registers and RSP replaces MSC/VLR MSCID with generic RSP MSCID• LCS Client queries H-MPC for roaming MS• H-MPC uses LOCREQ/SMSREQ to receive serving MSCID (that of the RSP) from HLR• H-MPC always creates IP connection (L3) with RSP• RSP maps MS IMSI in L3 messaging to V-MPC IP Address• RSP connects to V-MPC (passing serving MSCID) and provides response to H-MPC
RSP RSP
Home Operator Visited Operator
MSC/VLR
H-MPC
HLR
IS-41 Signaling
HLR
H-MPC
V-MPC V-PDELCS Client
IP Traffic
MSCID = RSP HLR
MSCID = RSP HLR
MSCID = MSC/VLR
IMSI maps to V-MPC
Page 9Next Steps
•Review and discuss Openwave’s RLP solution• Gap Analysis of RLP for IS-881 support
– Openwave’s changes and perhaps further enhancements
• Drive changes through OMA
•Review and discuss the RSP / CRX Issues