In this section:

Overview


You can deploy the SBC on the Access Edge and Peering Edge in an IMS/VoLTE network. On the Access Edge, the functional roles include: P-CSCF (IMS-AGW), E-CSCF, ATCF (ATGW) and EATF. On the Peering Edge the functional roles include: IBCF (TrGW).

The Proxy Call Session Control Function (P-CSCF) is the first point of contact in an IMS network. It is responsible for security associations towards the UE. At the time of UE registration, it inserts itself into the path so that it is in the signaling path for all subsequent messages. P-CSCF determines whether the UE is roaming or not. For a non-roaming UE that is, a UE in the home network, it forwards the registration messages towards the I-CSCF and directly contacts the S-CSCF for all subsequent messages. For a roaming UE, it selects a peering SBC (that is, IBCF) and forwards the SIP messages (including registration, call-related and non-call-related) towards the same.


IMPORTANT

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.

Deployment Scenario

The following deployment scenario shows the SBC acting as an Access SBC:

Figure 1: SBC IMS Deployment - SBC as Access SBC


Call Flows

Basic Registration Call Flow

Figure 2: Basic Registration Call Flow



The call flow description forFigure 2 is as follows:

  1. The Ribbon SBC, acting as an A-SBC, receives REGISTER request from UE.
  2. The SBC processes the REGISTER request. It acts as a B2BUA and changes Contact header to point itself and forwards the REGISTER request towards P-CSCF. The SBC does not insert a Path header as (external) P-CSCF does not expect a Path header from UE.
  3. The P-CSCF forwards REGISTER towards I/S-CSCF. P/I/S-CSCF responds to the REGISTER with 200 OK.
  4. The SBC stores the Path and Service-Route headers and forwards these headers transparently towards UE. It also processes, stores, and passes the P-Associated-URI header that is present in the 200 OK.

Originating Call from UE

Figure 3: Originating Call from UE


The call flow description for the Figure 3 is as follows:

  1. The Ribbon SBC, acting as an A-SBC, receives INVITE request from UE.
  2. The SBC forwards the INVITE towards the same P-CSCF to whom REGISTER was forwarded based on the local configuration,
    • The egress INVITE contains Route headers that point to P-CSCF (which is the next-hop stored in RCB) and Service-Route header(s) received in 200 OK to REGISTER.
    • It is noted that The Ribbon SBC does not support to apply default PUI procedures as P-CSCF function is not co-located and instead an external P-CSCF is present.

Configuring SBC Towards UE

Configure the following profiles first:


IMPORTANT

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.

Transparency Profile

set profiles services transparencyProfile TOWARDS_UE sipHeader To
set profiles services transparencyProfile TOWARDS_UE sipHeader From
set profiles services transparencyProfile TOWARDS_UE sipHeader Path
set profiles services transparencyProfile TOWARDS_UE sipHeader Accept
set profiles services transparencyProfile TOWARDS_UE sipHeader Reason
set profiles services transparencyProfile TOWARDS_UE sipHeader Server
set profiles services transparencyProfile TOWARDS_UE sipHeader Warning
set profiles services transparencyProfile TOWARDS_UE sipHeader Call-Info
set profiles services transparencyProfile TOWARDS_UE sipHeader Alert-Info
set profiles services transparencyProfile TOWARDS_UE sipHeader Error-Info
set profiles services transparencyProfile TOWARDS_UE sipHeader User-Agent
set profiles services transparencyProfile TOWARDS_UE sipHeader Referred-By excludedMethods register,subscribe,info,publish,message,options,update,bye
set profiles services transparencyProfile TOWARDS_UE sipHeader Request-URI
set profiles services transparencyProfile TOWARDS_UE sipHeader Accept-Language
set profiles services transparencyProfile TOWARDS_UE sipHeader P-Called-Party-Id
commit
set profiles services transparencyProfile TOWARDS_UE sipMessageBody application/pidf+xml
set profiles services transparencyProfile TOWARDS_UE sipMessageBody application/rlmi+xml
set profiles services transparencyProfile TOWARDS_UE sipMessageBody message/external-body
set profiles services transparencyProfile TOWARDS_UE sipMessageBody application/pidf+xml
set profiles services transparencyProfile TOWARDS_UE sipMessageBody application/cpim-pidf+xml
set profiles services transparencyProfile TOWARDS_UE sipMessageBody application/pidf-diff+xml
set profiles services transparencyProfile TOWARDS_UE sipMessageBody application/dialog-info+xml
set profiles services transparencyProfile TOWARDS_UE sipMessageBody application/simple-filter+xml
set profiles services transparencyProfile TOWARDS_UE sipMessageBody application/resource-lists+xml
set profiles services transparencyProfile TOWARDS_UE sipMessageBody application/conference-info+xml
set profiles services transparencyProfile TOWARDS_UE sipMessageBody application/simple-message-summary
set profiles services transparencyProfile TOWARDS_UE sipMessageBody application/vnd.3gpp.srvcc-ext ignoreTransparency yes
commit
set profiles services transparencyProfile TOWARDS_UE state enabled
commit
set addressContext default zone ZONE_ACCESSNW sipTrunkGroup TG_TOWARDS_UE services transparencyProfile TOWARDS_UE
commit

Trunk Group Configuration Towards UE

set addressContext default ipInterfaceGroup LIG1 ipInterface LIF1 ceName SBX30 portName pkt0 ipAddress 10.7.14.125 prefix 16
commit
set addressContext default ipInterfaceGroup LIG1 ipInterface LIF1 mode inService state enabled
commit
set addressContext default zone ZONE_ACCESSNW id 2 sipSigPort 1 state enabled ipAddressV4 10.7.14.126 portNumber 5060 ipInterfaceGroupName LIG1 transportProtocolsAllowed sip-udp,sip-tcp,sip-sctp,sip-tls-tcp
commit
set addressContext default zone ZONE_ACCESSNW sipTrunkGroup TG_TOWARDS_UE mode inService state enabled media mediaIpInterfaceGroupName LIG1
commit
set addressContext default zone ZONE_ACCESSNW sipTrunkGroup TG_TOWARDS_UE ingressIpPrefix 10.70.0.0 16
commit
set addressContext default staticRoute 10.70.0.0 16 10.7.1.1 LIG1 LIF1 preference 100
commit
set addressContext default staticRoute 10.54.0.0 16 10.7.1.1 LIG1 LIF1 preference 100
commit
set addressContext default zone ZONE_ACCESSNW sipTrunkGroup TG_TOWARDS_UE signaling registration requireRegistration required-nonpriority
set addressContext default zone ZONE_ACCESSNW sipTrunkGroup TG_TOWARDS_UE callRouting useRouteSet rcbNextHopAndStored 
set profiles signaling ipSignalingProfile IPSP_PCSCF egressIpAttributes privacy transparency enable
commit
set addressContext default zone ZONE_ACCESSNW sipTrunkGroup TG_TOWARDS_UE services preconditions transparent
commit

IPSec Support for SBC with External P-CSCF

set profiles services sipSecurityProfile IPSEC_SBC sbxSecMode sbc-pcscf
set profiles services sipSecurityProfile IPSEC_SBC sipSecurityMechanism ipsec-3gpp precedence 1
commit
set addressContext default ipInterfaceGroup LIG1 ipsec enabled
commit
set addressContext default zone ZONE_ACCESSNW sipTrunkGroup TG_TOWARDS_UE services sipSecurityProfile IPSEC_SBC
commit
set addressContext default ipsec spd spd1 action bypass localIpAddr 10.54.54.27 localIpPrefixLen 32 localPort 5060 precedence 10 state enabled
set addressContext default ipsec spd spd2 action bypass localIpAddr 10.54.54.27 localIpPrefixLen 32 localPort 5061 precedence 11 state enabled
commit

Non-register Routing Configuration

set addressContext default zone ZONE_ACCESSNW sipTrunkGroup TG_TOWARDS_UE callRouting useRouteSet rcbNextHopAndStored
commit

Zone Index Profile

The following flags must be configured under PSX Zone Index Profile:

  • Zone Index Profile
  • Description
  • Zone Index
    Figure 4: Zone Index Profile

IP Signaling Profile

The following parameters should be configured under IP Signaling Profile object:

Common Ip Attributes

The following Common IP Attributes flags must be enabled in PSX under IP SIGNALING PROFILE:

  • No Port Number 5060
  • Reject REFER
  • ReQuery PSX on REGISTER Refresh
  • Disable Host Translation
  • End to End BYE
  • End to End re-INVITE
  • End to End UPDATE
  • Store P-Charging-Vector
  • Validate Access Nw Info Header

    Figure 5: Ip Signaling Profile Common Ip Attributes

Relay Flags

The following Relay Flags must be enabled under Ip Signaling profile:

  • Dialog Event Package
  • Info
  • Options
  • Select Reject the REFER request if no match is found from Refer To Header Relay option.
    Figure 6: Ip Signaling Profile Relay Flags

Transparency Flags

The following Transparency Flags must be enabled under Ip Signaling profile:

  • Contact Header*
    Figure 7: Ip Signaling Profile Transparency Flags

Egress IP Attributes

The following Egress IP Attributes flags must be enabled:

  • Select SIP Only from IP Protocol Type.
  • BCI Interwork Encountered (in BCI option)
  • Transparency (in Privacy option)
  • Merge Received Contacts with Existing Contacts (in Redirect option)
  • Select Include None from Include Charge Information (in SIP Headers and Parameters option).
  • Select None from SIP TO Header Mapping (in SIP Headers and Parameters option).
  • Include OLIP (in SIP Headers And Parameters > Flags option)
  • Transparency For Destination Trunk Group Parameter (in SIP Headers And Parameters > Flags option)
  • End To End Ack (in SIP Headers And Parameters > Flags option)
  • Diversion (in SIP Headers And Parameters > Call Forwarding option)
    Figure 8: Ip Signaling Profile Egress Ip Attributes

Ingress IP Attributes

The following Ingress IP Attributes flag must be enabled:

  • 181 Supported (in Flags option)
    Figure 9: Ip Signaling Profile Ingress Ip Attributes

SIP Trunk Group

Execute the following command:

 set addressContext "default" zone "ZONE_ACCESSNW" sipTrunkGroup "TG_TOWARDS_UE" media mediaIpInterfaceGroupName "LIF1"
commit
set addressContext "default" zone "ZONE_ACCESSNW" sipTrunkGroup "TG_TOWARDS_UE" state "enabled" mode "inService" media mediaIpInterfaceGroupName "LIF1"
commit

Figure 10: UE TG

Configuring SBC towards IMS Core

The following profiles are configured:


IMPORTANT

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.

set profiles services transparencyProfile TRANS_PROF_CORENW sipHeader To
set profiles services transparencyProfile TRANS_PROF_CORENW sipHeader From
set profiles services transparencyProfile TRANS_PROF_CORENW sipHeader Path
set profiles services transparencyProfile TRANS_PROF_CORENW sipHeader Accept
set profiles services transparencyProfile TRANS_PROF_CORENW sipHeader Reason
set profiles services transparencyProfile TRANS_PROF_CORENW sipHeader Server
set profiles services transparencyProfile TRANS_PROF_CORENW sipHeader Warning
set profiles services transparencyProfile TRANS_PROF_CORENW sipHeader Call-Info
set profiles services transparencyProfile TRANS_PROF_CORENW sipHeader Alert-Info
set profiles services transparencyProfile TRANS_PROF_CORENW sipHeader Error-Info
set profiles services transparencyProfile TRANS_PROF_CORENW sipHeader User-Agent
set profiles services transparencyProfile TRANS_PROF_CORENW sipHeader Referred-By excludedMethods register,subscribe,info,publish,message,options,update,bye
set profiles services transparencyProfile TRANS_PROF_CORENW sipHeader Request-URI
set profiles services transparencyProfile TRANS_PROF_CORENW sipHeader Accept-Language
set profiles services transparencyProfile TRANS_PROF_CORENW sipHeader P-Called-Party-Id
set profiles services transparencyProfile TRANS_PROF_CORENW sipHeader Require
set profiles services transparencyProfile TRANS_PROF_CORENW sipHeader Proxy-Require
set profiles services transparencyProfile TRANS_PROF_CORENW sipHeader Security-Client
set profiles services transparencyProfile TRANS_PROF_CORENW sipHeader Security-Verify
commit
set profiles services transparencyProfile TRANS_PROF_CORENW sipMessageBody application/pidf+xml excludedMethods register,invite,subscribe,info,publish,message,options,update,bye
set profiles services transparencyProfile TRANS_PROF_CORENW sipMessageBody application/pidf+xml
set profiles services transparencyProfile TRANS_PROF_CORENW sipMessageBody application/rlmi+xml
set profiles services transparencyProfile TRANS_PROF_CORENW sipMessageBody message/external-body
set profiles services transparencyProfile TRANS_PROF_CORENW sipMessageBody application/pidf+xml
set profiles services transparencyProfile TRANS_PROF_CORENW sipMessageBody application/cpim-pidf+xml
set profiles services transparencyProfile TRANS_PROF_CORENW sipMessageBody application/pidf-diff+xml
set profiles services transparencyProfile TRANS_PROF_CORENW sipMessageBody application/dialog-info+xml
set profiles services transparencyProfile TRANS_PROF_CORENW sipMessageBody application/simple-filter+xml
set profiles services transparencyProfile TRANS_PROF_CORENW sipMessageBody application/resource-lists+xml
set profiles services transparencyProfile TRANS_PROF_CORENW sipMessageBody application/conference-info+xml
set profiles services transparencyProfile TRANS_PROF_CORENW sipMessageBody application/simple-message-summary
commit
set profiles services transparencyProfile TRANS_PROF_CORENW state enabled
commit
set addressContext default zone ZONE_CORENW sipTrunkGroup TG_TOWARDS_IMSCORE services transparencyProfile TRANS_PROF_CORENW
commit

Trunk Group Configuration Towards P-CSCF

set addressContext default ipInterfaceGroup LIG2 ipInterface LIF2 ceName SBX30 portName pkt2 ipAddress 10.8.14.125 prefix 16
commit
set addressContext default ipInterfaceGroup LIG2 ipInterface LIF2 mode inService state enabled
commit
set addressContext default zone ZONE_CORENW id 3 sipSigPort 2 state enabled ipAddressV4 10.8.14.125 portNumber 5060 ipInterfaceGroupName LIG2 transportProtocolsAllowed sip-udp,sip-tcp,sip-sctp,sip-tls-tcp
commit
set addressContext default zone ZONE_CORENW sipTrunkGroup TG_TOWARDS_IMSCORE mode inService state enabled media mediaIpInterfaceGroupName LIG2
commit
set addressContext default zone ZONE_CORENW sipTrunkGroup
TG_TOWARDS_IMSCORE ingressIpPrefix 10.54.93.181 32
commit
set addressContext default zone ZONE_CORENW ipPeer
PEER_PCSCF policy sip fqdn pcscf.open-ims.test fqdnPort 4060
commit
set addressContext default staticRoute 10.54.93.181 32 10.8.1.1 LIG2 LIF2 preference 100
commit
set addressContext default zone ZONE_CORENW sipTrunkGroup
TG_TOWARDS_IMSCORE services preconditions transparent 
commit

Zone Index Profile

The following flags must be configured:

  • Zone Index Profile
  • Description
  • Zone Index
    Figure 11: Zone Index Profile IMS

IP Signaling Profile

The following parameters must be configured under "Ip Signaling Profile".

Configuring Common IP Attributes

Enable the following fields on the PSX under IP SIGNALING PROFILE:

  • Add P-Charging Function Addr
  • Create P-Charging-Vector
  • Create P-Visited-Network Id
  • Customized Session Timer Behavior
  • Disable Host Translation
  • End To End BYE
  • End To End re-INVITE
  • End To End UPDATE
  • End To End PRACK
  • Enable Default PUI Procedures
  • Enable Dial String Handling
  • No Port Number 5060
  • P-Called-Party0Id-Support
  • Restrict History Info Header
  • Store P-Charging Vector
  • Store Service-Route Header
  • Validate Access Nw Info Header
    Figure 12: Common IP Attributes for IMS

Configuring Relay Flags

Enable the following Relay Flags under Ip Signaling profile:

  • Dialog Event Package
  • Info
  • Options
  • Reg Event Package
  • Select Reject the REFER request if no match is found from Refer to Header Relay option.
    Figure 13: Relay Flags for IMS

Configuring Egress IP Attributes

Enable the following parameters :

  • Select SIP Only from IP Protocol Type
  • Select Transit PAI From Unregistered Peer from Flags
  • Select Use IP Signaling Peer Domain In R-URI (in Domain Name)
  • Select Include npdi from NPDI Options (in Number Portability Attributes option).

  • Select P-Preferred-ID from Privacy Information options (in Privacy option).

  • Select Include Privacy (in Privacy)
  • Select Merge Received Contacts with Existing Contacts from Contact Handling(under Redirect)
  • Select Include None from Include Charge Information (in SIP Headers and Parameters option).
  • Select Not Send from Session-Expires Refresher (in SIP Headers and Parameters option).

  • Select None from SIP TO Header Mapping (under SIP Headers And Parameters option).

  • Select Transparency For Destination Trunk Group Parameter(under Flags option)
  • Select End to End Ack (under Flags option)
  • Select Diversion from Redirect Information (under Call Forwarding)
    Figure 14: Egress IP Attributes for IMS

SIP Trunk Group

Enable the following profiles/fields:

  • Feature Control Profile
  • IP Signaling Profile
  • Signaling Profile
  • SIP Domain
  • Zone Index Profile
  • 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 15: SIP Trunk Group for IMS



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