Routing for Route Header
The routing parameter, useRouteSet, is used in conjunction with the PSX in the context of performing its routing logic (i.e gathering the address of the called party for instance). In this way, routing information can be sent from the
to the PSX and Destination Trunk Group (DTG) using the route sent by
the PSX for REGISTER request.
The
determines whether the PSX should perform pattern matching logic or not using "
skipPatternMatching
" option of SIP trunk group's
useRouteSet
parameter. If this indication is set, the PSX returns the destination routing information provided to it in the Routing AVP of the Policy request back to the
in the Policy response. For more information on Pattern Matching by the PSX, refer to
PSX Documentation.
This feature also allows the
to eliminate all the extraneous routing decisions and always uses the information returned to it by the PSX in the policy response to determine the next immediate destination.
SBC Route Set Options
The below useRouteSet
options describes the various routing scenarios supported by the
.
- Stored -- This legacy option is used for P-CSCF functionality in supporting Registration for generic IMS support. Beginning with 5.0 release, the is enhanced with the following capability to support conditional use of PSX routing.
This option is used along with the flag "sendRouteUriToPsx
" (see SIP Trunk Group - Call Routing - CLI for CLI details).
When you enable
sendRouteUriToPsx
flag, the Stored service Route or Path header is sent to the PSX.
The
sends Stored Service-Route or Path along with the DTG route information to the PSX .The PSX sends back the route to the
with the exact route information.
When you disable
sendRouteUriToPsx
option, route-URI is not sent to the PSX.
Note |
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The stored service-Routes will be used for UE originated calls and path headers will be used for UE terminating calls. |
Roaming or Stored – This option is used in P-CSCF for supporting the roaming as well as non-roaming scenarios. This option is used along with the "sendRouteUriToPsx
" flag.
For Roaming UserThe register URI routing information is send to the PSX.
The
sends URI along with the DTG route information to the PSX .The PSX sends back the route to SBC with the exact route information.
For Non-Roaming User
The register URI routing information is send sent to the PSX.
The
sends route URI along with DTG route information.Set SkipPatternMatch
flag to TRUE.
Rcb Next Hop And Stored – This option is used when the operator wants to ensure the messages from registered subscriber go to the same next immediate destination as the registration.
When using this option, ensure "sendRouteUriToPsx
" flag is enabled.
If you enable sendRouteUriToPsx
option, the register URI routing information (registrar IP along with the DTG route information) is send sent to the PSX.
Received
This is a legacy option. This option is used for the IBCF functionality when stateless Registration Relay is in effect. This indicates that the routing information received in the route header portion of the incoming message. This routing information is used for determining the next immediate destination route.
This option is used along with the "sendRouteUriToPsx
" option to either enable/disable
. You need to also enable " skipDTGLookupForRouteHdr
" to use the received option.
When you enable
sendRouteUriToPsx
option, the top-most non-
Route-URI is sent to the PSX.- When you
disable
sendRouteUriToPsx
option, route-URI is not sent to the PSX.
Identifying Roaming User and Routing for Loop Back Scenario
The
as a P-CSCF marks a registered user as roaming based on the data provided by PSX in the policy response of a REGISTER message, and also routes the Non-REGISTER message from roaming UE based on DTG provided by
the PSX during REGISTRATION. Additional
routing functionality is described below.
SBC as P-CSCF
SBC as IBCF
Honor PSX Route during Roaming Based Routing (PCSCF) or Route-URI Based Routing (IBCF)
- If
useRouteSet
is set to roamingOrStored
and UE is Roaming User, the PSX route is honored. - If
useRouteSet
is received and ROUTE-URI is passed to the PSX, the PSX route is honored.
Simplified Call Flow for Roaming UE Registration and Call Origination
Below is a simplified call flow diagram depicting call origination and REGISTRATION of roaming UE.
Caption |
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0 | Figure |
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1 | Roaming UE Call Flow Diagram |
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3 | Roaming UE Call Flow Diagram |
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