IMS Registration Overview
|
The following diagram provides a single sheet
overview of the message interactions involved in IMS registration.
Interaction details and remarks are omitted from the diagram.
 IMS
Registration Overview
pdf |
IMS Registration (High Level Diagram)
|
The visited network first performs an
unauthenticated registration with the home network. This is followed up with
an authenticated registration.
Registration
Interactions between Visited and Home IMS Networks
pdf |
IMS Registration (Interactions between UE,
Visited and Home Networks)
|
The following diagram adds more details.
Interactions between the UE, Visited and Home network are covered. The
diagram also shows the message exchanges involving subscriber and the
subscriber database HSS (represented as the Home Core Network).
Registration
Interactions between User Equipment, the Visited Network and the Home
IMS Network
pdf |
User Equipment (UE) Role
|
UE is the initiator of the registration
sequence It performs the following steps:
- Attach and PDP context activation
- Unauthenticated registration attempt.
- IPSec Security Association
establishment
- Authenticated registration
UE
Role Sequence Diagram
pdf
UE
Role Collaboration Diagram
pdf |
P-CSCF Role
|
The P-CSCF resides in the visited network. It
acts as the UE's gateway into the UE's home network. The P-CSCF is
responsible for:
- Identifying the home IMS network.
- Routing traffic to and from the home
IMS network.
- Establishing the IPSec security
association
P-CSCF
Role Sequence Diagram
pdf
P-CSCF
Role Collaboration Diagram
pdf |
I-CSCF Role
|
The I-CSCF resides in the home network. It
acts as the front-end of the Home IMS network. The I-CSCF is responsible
for:
- Interfacing with the P-CSCF in the
visited network.
- Selecting the S-CSCF by querying the
HSS.
I-CSCF
Role Sequence Diagram
pdf
I-CSCF
Role Collaboration Diagram
pdf |
S-CSCF Role
|
The S-CSCF resides in the home network. The S-CSCF is responsible
for:
- Handling the registration request
from the I-CSCF.
- Pulling the authentication vectors
from the HSS
- Passing the authentication vectors to
the P-CSCF via the I-CSCF.
- Authenticate the user in the second
registration attempt.
S-CSCF
Role Sequence Diagram
pdf
S-CSCF
Role Collaboration Diagram
pdf |
Role Wise Summary
|
|
Role wise summary of all the components
involved in IMS registration.
IMS
Registration Role Wise Summary |
