In this section:
Overview
Ribbon recommends using the Transparency Profile to configure transparency on the SBC Core for new deployments, as well as applying additional transparency configurations to existing deployments. Do not use IP Signaling Profile flags in these scenarios because the flags will be retired in upcoming releases.
Refer to the SBC SIP Transparency Implementation Guide for additional information.
At a high level, the functions performed by the EATF are:
- The EATF provides IMS-based mechanisms for enabling service continuity of IMS emergency sessions. It is a function in the serving (visited if roaming) IMS network, which provides the procedures for IMS emergency session anchoring and PS to CS Access Transfer.
- The EATF acts as a routing B2BUA, which invokes third party call control (3pcc) to enable access transfer.
- The EATF performs the session continuity when the access transfer request indicated by the E-STN-SR is received.
Deployment Scenario
Figure 1: SBC IMS Deployment - A-SBC as EATF Provisioning
Call Flow
Figure 2: EATF call flow
he call flow description for Figure 2is as follows:
- The Ribbon SBC, acting as an A-SBC and EATF, receives INVITE request from UE.
- The SBC forwards the INVITE to the same P-CSCF to whom the original REGISTER is sent.
- The P-CSCF forwards to the E-CSCF.
- The E-CSCF invokes the EATF so that the call is anchored for a future handover. The E-CSCF adds two Route headers – one pointing to EATF and another pointing itself (E-CSCF).
- The EATF deletes the top route header pointing to itself and anchors the emergency session.
- The EATF loops back the call towards the E-CSCF based on the top route header (that points E-CSCF) from the remaining route header list.
- The E-CSCF forwards it to the PSAP.
In the remaining steps, the 200 OK SIP response is forwarded as appropriate.
Configuration
Global Configuration
- EATF Configuration
- Emergency Profile Configuration
- Trunk Group Towards E-CSCF
- Precondition Support
- Attaching EATF Profile to IPSP
EATF Configuration
set global signaling srvcc eStnSr +1-237-555-5555 callLingerTimer 32 set addressContext default zone ZONE_CORENW srvcc eatf enabled set addressContext default zone ZONE_CORENW dialogTransparency disabled set addressContext default zone ZONE_CORENW disableZoneLevelLoopDetection enabled
Emergency Profile Configuration
set profiles services sipResourcePriorityHeaderProfile "RPH-1" rphEmergencyMatchingConfig "esnet" "1" commit set profiles services sipResourcePriorityHeaderProfile "RPH-1" sendEgressRphForEmergency esnet 1 commit set profiles services emergencyCallProfile "EMG-ECSCF" resPriorityHeaderProfile "RPH-1" sosInContactOfRegister "enable" commit set profiles services emergencyCallProfile EMG-ECSCF prefix 911 comm set profiles services emergencyCallProfile EMG-ECSCF urnPrefix service:sos.fire comm set profiles services emergencyCallProfile EMG-ECSCF sosInContactOfRegister enable comm
Trunk Group Towards E-CSCF
set addressContext default zone ZONE_ECSCF sipTrunkGroup TG_TOWARDS_ECSCF signaling registration requireRegistration required-nonpriority useRUriForRegisterRouting enabled set addressContext default zone ZONE_ECSCF sipTrunkGroup TG_TOWARDS_ECSCF signaling prefRequireTransparency "enabled" deRegParentWithChildDereg "enabled" validateAor "enabled" condIncMethInAllowHdr "enabled" usePsxRouteForEmergencyCall "enabled" set addressContext default zone ZONE_ECSCF sipTrunkGroup TG_TOWARDS_ECSCF callRouting useRouteSet rcbNextHopAndStored set profiles signaling ipSignalingProfile IPSP_PCSCF egressIpAttributes privacy transparency enable set addressContext default zone ZONE_ECSCF sipTrunkGroup TG_TOWARDS_ECSCF services emergencyCallProfile EMG-ECSCF
Precondition Support
set addressContext default zone ZONE_CORENW sipTrunkGroup TG_TOWARDS_IMSCORE services preconditions transparent set addressContext default zone ZONE_ECSCF sipTrunkGroup TG_TOWARDS_ECSCF services preconditions transparent commit
Attaching EATF Profile to IPSP
Select "EATF" profile from the "Access Transfer Policy Type" option.
Figure 3: Selecting EATF ProfileAttach the "EATF" profile to the Ip signaling profile of a Trunk Group.
Figure 4: Attaching EATF profile to the IPSP Trunk group
Configuring SBC Towards E-CSCF
The following profiles are configured:
Transparency Profile
set profiles services transparencyProfile TRANS_PROF_ECSCF sipHeader To set profiles services transparencyProfile TRANS_PROF_ECSCF sipHeader From set profiles services transparencyProfile TRANS_PROF_ECSCF sipHeader Path set profiles services transparencyProfile TRANS_PROF_ECSCF sipHeader Accept set profiles services transparencyProfile TRANS_PROF_ECSCF sipHeader Reason set profiles services transparencyProfile TRANS_PROF_ECSCF sipHeader Server set profiles services transparencyProfile TRANS_PROF_ECSCF sipHeader Warning set profiles services transparencyProfile TRANS_PROF_ECSCF sipHeader Call-Info set profiles services transparencyProfile TRANS_PROF_ECSCF sipHeader Alert-Info set profiles services transparencyProfile TRANS_PROF_ECSCF sipHeader Error-Info set profiles services transparencyProfile TRANS_PROF_ECSCF sipHeader User-Agent set profiles services transparencyProfile TRANS_PROF_ECSCF sipHeader Referred-By excludedMethods register,subscribe,info,publish,message,options,update,bye set profiles services transparencyProfile TRANS_PROF_ECSCF sipHeader Request-URI set profiles services transparencyProfile TRANS_PROF_ECSCF sipHeader Accept-Language set profiles services transparencyProfile TRANS_PROF_ECSCF sipHeader P-Called-Party-Id set profiles services transparencyProfile TRANS_PROF_ECSCF sipHeader Require set profiles services transparencyProfile TRANS_PROF_ECSCF sipHeader Proxy-Require set profiles services transparencyProfile TRANS_PROF_ECSCF sipHeader Security-Client set profiles services transparencyProfile TRANS_PROF_ECSCF sipHeader Security-Verify commit set profiles services transparencyProfile TRANS_PROF_ECSCF sipMessageBody application/pidf+xml excludedMethods register,invite,subscribe,info,publish,message,options,update,bye set profiles services transparencyProfile TRANS_PROF_ECSCF sipMessageBody application/pidf+xml set profiles services transparencyProfile TRANS_PROF_ECSCF sipMessageBody application/rlmi+xml set profiles services transparencyProfile TRANS_PROF_ECSCF sipMessageBody message/external-body set profiles services transparencyProfile TRANS_PROF_ECSCF sipMessageBody application/pidf+xml set profiles services transparencyProfile TRANS_PROF_ECSCF sipMessageBody application/cpim-pidf+xml set profiles services transparencyProfile TRANS_PROF_ECSCF sipMessageBody application/pidf-diff+xml set profiles services transparencyProfile TRANS_PROF_ECSCF sipMessageBody application/dialog-info+xml set profiles services transparencyProfile TRANS_PROF_ECSCF sipMessageBody application/simple-filter+xml set profiles services transparencyProfile TRANS_PROF_ECSCF sipMessageBody application/resource-lists+xml set profiles services transparencyProfile TRANS_PROF_ECSCF sipMessageBody application/conference-info+xml set profiles services transparencyProfile TRANS_PROF_ECSCF sipMessageBody application/simple-message-summary commit set profiles services transparencyProfile TRANS_PROF_ECSCF state enabled commit set addressContext default zone ZONE_ECSCF sipTrunkGroup TG_TOWARDS_ECSCF services transparencyProfile TRANS_PROF_ECSCF commit
Zone Index Profile
The following fields must be configured:
- Zone Index Profile
- Description
- Zone Index
Figure 5: PSX IPSP Zone Index Profile
Ip Signaling Profile
Common Ip Attributes
The following "Common IP Attributes" must be enabled in PSX under "IP SIGNALING PROFILE":
- Disable Host Translation
- End to End BYE
- End to End re-INVITE
- End to End UPDATE
- End to End PRACK
- Insert Peer Address As Top Route Header
- No Port Number 5060
- ReQuery PSX on REGISTER Refresh
- Store P-Charging-Vector
- Validate Access Nw Info Header
Figure 6: PSX IPSP Common Ip Attributes
Relay Flags
The following "Relay Flags" must be enabled under "Ip Signaling profile":
- Conference Event Package
- Dialog Event Package
- Info
- Message
- Options
- PUBLISH
- REFER
- Reg Event Package
- Status Code 4XX-6XX
- Select Reject the REFER request if no match is found from Refer To Header Relay option.
Figure 7: PSX IPSP Common Ip Attributes Relay Flags
Transparency Flags
The following "Transparency Flag" must be enabled under "Ip Signaling Profile":
- Request-URI
Figure 8: PSX IPSP Common Ip Attributes Transparency Flags
The following "Egress IP Attributes" must be enabled:
- Select SIP Only from IP Protocol Type.
- Disable 2806 Compliance (under Flags)
- Transit PAI From Unregistered Peer (under Flags)
- Add Loop Back Route Header (under Flags)
- Select Include npdi from NPDI Options (under Number Portability Attributes option).
- Select P-Preferred-ID from Privacy Information (under Privacy option).
- Merge Received Contacts with Existing Contacts (under Redirect)
- Select Include None from Include Charge Information option (under SIP Headers and Parameters)
- Select Original Called Number (OCN) from SIP TO Header Mapping option (under SIP Headers and Parameters)
- Include CPC Information (under SIP Headers and Parameters > Flags)
- Transparency For Destination Trunk Group Parameter (under SIP Headers and Parameters > Flags)
- End To End Ack (under SIP Headers and Parameters > Flags)
- Diversion (under SIP Headers and Parameters > Call Forwarding)
- Select Retry Without ETS from the Action For ETS 400 Responses With 417 Reason Code drop-down box (under SIP RPH ETS)
- Set ETS Default Priority Value as 0 (under SIP RPH ETS)
Figure 9: PSX IPSP Common Ip Attributes Egress Ip Attributes
Ingress Ip Attributes
The following "Ingress IP Attributes" must be enabled:
- 181 Supported (under Flags option)
Figure 10: PSX IPSP Common Ip Attributes Ingress Ip Attributes
Sip Trunk Group
The following profiles/fields must be enabled:
- Zone Index Profile
- IP Signaling Profile
- Feature Control Profile
- Signaling Profile
- SIP Domain
- IP Version Preference
- Use IPTG Routing (Hop By Hop Routing) For Ingress (Ingress > Flags)
- Do Not Use For Fallback Bearer Capability (Egress > Flags)
- IP Peer Supported (Egress > IPTG)
- Egress IP Signaling Profile (Egress > IPTG)
- Select Traffic Management Options from Trunk Group Reserved Level 1 and Trunk Group Reserved Level 2.
- Select Services as Not Screened.
Figure 11: PSX IPSP Sip Trunk Group towards E-CSCF
Configuring SBC Towards MSC
For configuring SBC towards MSC, refer to Configuring SBC Towards MSC.