Gnenral P CSCF Architecture
Gnenral P CSCF Architecture
Gnenral P CSCF Architecture
James Ni
July.18th, 2012
IMS Architecture
P-CSCF/AGW Architecture
Validates registration
Multiple IMPU
Resolves home domain address
Establishes security associations
Acts as SIP UA
3rd party registration on behalf of UE
Session control on behalf of UE
Subscriber information exchange with S-CSCF etc.
Supports PCRF/PDF
Interacts with external PCRF/PDF
Implements internal PDF
QoS/Advanced QoS Features
Mobility Support
Visited P-CSCF functions
Lawful Intercept
Access Transfer Control Function (ATCF)
Media Security
Media Access Transfer Gateway (ATGW)
10
11
12
13
14
15
16
17
18
19
20
21
SDP Examination
AGW control procedure
ECN
OMR
IP Interworking
Hosted NAT
NAT Traversal
Media Address Translation
NA(P)T and NA(P)T-PT
ICE
Security
Media Security
Transcoding
22
SDP Examination
23
3GPP TS 23.334
24
3GPP TS 23.334
25
Intermediate IMS
CN subsystem entities
190.1.15.2
190.1.15.3
IBCF-2
IBCF-3
TrGW
TrGW
13.24.1.2
13.24.1.3
13.24.1.1
UE-A
IBCF-1
13.24.1.4
UE-B
IBCF-4
P-CSCF B
P-CSCF A
TrGW
192.0.2.1
TrGW
PCRF
PCRF
192.0.2.2
192.0.2.3
PDNGW
PDNGW
Visited network X:
Realm Xa.operatorX.net
3GPP TS 29.079
26
192.0.2.4
27
28
29
30
IP Interworking
NAT Traversal
Hosted NAT
Both signaling and media paths traverse a NA(P)T device located in the customer
premises domain
Modify IP and port based on IP and port received from (for?) AGW
34
35
36
IP Interworking: ICE
STUN/TURN Client function
STUN/TURN Server function
Transportation: UDP, TCP, TLS-TCP
37
Transcoding Control
38
Security
Signaling Security
AKA, IPSec ESP
TLS
Media Security
39
P-CSCF: Security
40
Authentication
Integrity
protection
Use of security
agreement in accordance
with RFC 3329 [48]
IMS AKA
IPsec ESP
Yes
SIP digest
None (note 3)
No
SIP digest
None (note 3)
No
SIP digest
TLS session
Yes
NASS-IMS bundled
authentication (notes 4, 5)
not applicable
(note 1)
None
(note 3)
No
GPRS-IMS-Bundled
authentication (note 5)
not applicable
(note 1)
None (note 3)
No
NOTE 1:
NOTE 2:
NOTE 3:
NOTE 4:
NOTE 5:
NOTE 6:
3GPP TS24.229
41
42
43
44
45
Applicable to media
Support required by UE
Support required by IM
CN subsystem entities
End-to-access-edge
media security using
SDES.
P-CSCF (IMS-ALG) is
required.
P-CSCF needs to support
RFC 3329 additions
specified in draft-dawesdispatch-mediasecparameter [174] and
SDP extensions specified
in table A.317, items
A.317/34, A.317/36 and
A.317/37.
(NOTE)
End-to-end media
security using SDES.
Not applicable.
Not applicable.
End-to-end media
security using KMS.
Not applicable.
NOTE:
Network support
outside IM CN
subsystem entities
Not applicable.
Support of end-to-access-edge security is determined entirely by the network operator of the P-CSCF, which need not be
the same network operator as that of the S-CSCF.
Irrespectively of key management solution used, SRTP is used as the security protocol to protect RTP based traffic.
3GPP TS24.229
46
3GPP TS33.328
47
3GPP TS33.328
48
3GPP TS33.328
49
50
location is used to
determine PSAP
U
E
SIP
Access
DNS
ENUM
RTP
RTP
Customer
Access
Network
HSS
Diameter
SIP
Backbone
Packet
Network
LRF/RDF
AS
AS
SIP
SIP
P-CSCF
I-CSCF
SIP
S-CSCF
IP PSAP
P-CSCF
SIP
SIP
SIP
RTP
MRFC
SIP
RTP
SIP
BGCF
Call enters IMS with
location info
RTP
MS
SIP
SIP
MGCF
ISUP
IMS Emergency
Services Network
H.248
MGW
TDM
CAMA
E-MF
51
SS7
CAMA
E-MF
Legacy
PSAP
52
P-CSCF shall
Store a configurable list of local ECS identifiers (ECS number, URN)
Store a configurable list of roaming partners ECS identifiers
53
P-CSCF: Charging
54
3GPP TS22.115
55
CS - NE
Service - NE
SIP AS
MRFC
CGF
CDF
MGCF
BGCF
IBCF
P-CSCF
I-CSCF
OCS
IMSGWF
S-CSCF
WLAN
SGSN
ePDG
S-GW
MME
P-GW
PCEF
OFFLINE
CHARGING
PCRF
ONLINE
AF
3GPP TS32.240
56
CHARGING
Bi
Rf
CGF
CDF
Ga
Rf
BGCF
SIP
AS
MGCF
MRFC
Rf
Rf
MRFC
MGCF
SIP AS
Rf
Rf
P-CSCF
I-CSCF
Rf
S-CSCF
Rf
IBCF
Rf
E-CSCF
3GPP TS32.260
57
3GPP TS32.260
58
P-CSCF: ATCF
59
ATCF
ATCF inclusion
For roaming UEs
Based on local configuration, registered service, media capabilities, access type
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62
P-CSCF: Mobility
Roaming & Handover Capability
63
64
65
66
P-CSCF Mobility
Roaming Capability as a Visited P-CSCF
Optimal Media Routing (OMR)
Roaming charging
Home Routing
67
68
69
re-INVITE
70
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77
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79
80
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