Oracle Acme Packet outbound configuration for ClearIP

This documentation provides instructions on how to configure an Oracle Acme Packet Session Border Controller (SBC) with ClearIP for outbound calls. After the SBC has been configured according to these instructions, then SIP INVITES can be sent to ClearIP.

The diagram below provides an overview of how ClearIP is configured as a SIP end point with an SBC. A SIP INVITE is sent from the CFS (Call Feature Server) to the SBC. Then the SBC forwards the INVITE to ClearIP for services, such as fraud and robocall control.

If no fraud is detected, ClearIP returns a SIP 404 No Route Found message and the SBC forwards the INVITE to the original destination. If fraud is detected, ClearIP responds with a SIP 603 Decline message indicating the call should be blocked. The SBC forwards the SIP 603 Decline message to the CFS. ClearIP can also return a SIP 302 Moved Temporarily message with an alternative destination if the call should be diverted.

Outbound network call flow

Outbound network call flow

This documentation does not include SBC installation instructions, such as installing SBC VMware image, configuring network interfaces, etc. This work should be done by Oracle technical support.

We have provided separate instructions for Oracle Acme Packet SBC configuration for STIR/SHAKEN with ClearIP.

1. Outbound scenarios

ClearIP can be used for STIR/SHAKEN authentication, toll fraud prevention for outbound call scenarios and used for STIR/SHAKEN verification and robocall prevention for inbound call scenarios. In the inbound scenarios, SBC directly forwards the calls from source devices to ClearIP. In the outbound scenarios, SBC forwards the calls to ClearIP before sending them out to destinations. This documentation only discusses the outbound scenarios.

This section describes one outbound scenario that is commonly used by telephone service providers.

Original scenario without ClearIP

Original scenario without ClearIP

Key components

  • Core Network — The network inside the domain of the telephone service provider.
  • Access Network — The network outside the domain of the telephone service provider.
  • Call Feature Server — The server of the telephone service provider that provides routing, billing, etc. features.
  • SBC Internal Interface — The internal SIP interface configured on the SBC to connect to the Core Network.
  • SBC External Interface — The external SIP interface configured on the SBC to connect to the Access Network.
  • Network Gateway — The device in the Access Network that sends SIP calls from the telephone service provider.

Routing rules

  • CFS-L — Local policies configured on the Call Feature Server.
  • SBC-L1 — Local policies configured on the SBC for the SBC Internal Interface/Core Network.
  • SBC-L2 — Local policies configured on the SBC for the SBC External Interface/Access Network.

Note: There may be only one set of SBC local policies. We separate it into two sets of policies logically.

Data flow

  1. F1 — The Call Feature Server sends calls to the SBC Internal Interface based on the local policies CFS-L configured on the Call Feature Server.
  2. F2 — The SBC Internal Interface forwards the calls to the SBC External Interface based on the local policies SBC-L1 configured on the SBC for the SBC Internal Interface.
  3. F3 — The SBC External Interface forwards the calls to the Network Gateway based on the local policies SBC-L2 configured on the SBC for the SBC External Interface.

Proposed scenario with ClearIP

Proposed scenario with ClearIP

Key components

  • Core Network — The network inside the domain of the telephone service provider.
  • Access Network — The network outside the domain of the telephone service provider. ClearIP is typically in the Access Network.
  • Call Feature Server — The server of the telephone service provider that provides routing, billing, etc. features.
  • SBC Internal Interface — The internal SIP interface configured on the SBC to connect to the Core Network.
  • SBC External Interface — The external SIP interface configured on the SBC to connect to the Access Network.
  • ClearIP — The TransNexus STIR/SHAKEN, toll fraud prevention, and robocall prevention solution.
  • Network Gateway — The device in the Access Network that sends SIP calls from the telephone service provider.

Routing rules

  • CFS-L — Local policies configured on the Call Feature Server.
  • SBC-L1 — Local policies configured on the SBC for the SBC Internal Interface.
  • SBC-L2’ + SBC-L2 — Local policies configured on the SBC for the SBC External Interface. It includes the routing policy SBC-L2’ for ClearIP and the original local policies SBC-L2 configured on the SBC for the SBC External Interface.

Note: It may not be necessary to change SBC-L1 and SBC-L2.

Data flow

  1. F1 — The Call Feature Server sends calls to the SBC Internal Interface based on the local policies CFS-L configured on the Call Feature Server.
  2. F2 — The SBC Internal Interface forwards the calls to the SBC External Interface based on the local policies SBC-L1 configured on the SBC for the SBC Internal Interface.
  3. F2’ — The SBC External Interface forwards the calls to ClearIP for fraud detection based on the local policies SBC-L2’ configured on the SBC for the SBC External Interface for ClearIP.
  4. F2’’ — ClearIP sends a response to the SBC External Interface. If fraud is detected, then a SIP 603 Decline is sent to the SBC. The SBC External Interface forwards the SIP 603 Decline to the Call Feature Server and finishes the calls. If fraud is not detected, then a SIP 404 Not Found is sent to the SBC.
  5. F3 — The SBC External Interface forwards the calls to the Network Gateway based on the local policies SBC-L2 configured on the SBC for the SBC External Interface.

2. Basic configuration

This section provides the basic standard configuration for an SBC.

Network diagram

Network diagram

Network interface configuration

To access ClearIP by its FQDN (Fully Qualified Domain Name), sip.clearip.com, there must be at least one DNS server configured. The DNS server should be configured in the network-interface.

Important configuration items:

1.dns-ip-primary8.8.8.8
2.dns-ip-backup18.8.4.4

In the sample configuration below, Google is used as the DNS service provider. Google Public DNS IPv4 servers are configured on the external network interface, M11, which connects to the Access Network. Other DNS servers can be used too. For example, an internal DNS server of the telephone service provider in the Core Network can be configured on the internal network interface, M10, which connects to the Core Network. The desired DNS server IP addresses should be configured.

A previously existing network interface should be configured as shown below.

Highlighted items should be different from the default values. Non-highlighted values can be left as the SBC default values. Some highlighted values such as the name, ip-address, etc. should be left as the previously existing values.

  • Sample network configuration
    network-interface
        name                          M10
        sub-port-id                   0
        description
        hostname
        ip-address                    172.16.4.157
        pri-utility-addr
        sec-utility-addr
        netmask                       255.255.0.0
        gateway                       172.16.4.1
        sec-gateway
        gw-heartbeat
            state                     disabled
            heartbeat                 0
            retry-count               0
            retry-timeout             1
            health-score              0
        dns-ip-primary
        dns-ip-backup1
        dns-ip-backup2
        dns-domain
        dns-timeout                   11
        hip-ip-list
        ftp-address
        icmp-address
        snmp-address
        telnet-address
        ssh-address
        signaling-mtu                 0
    network-interface
        name                          M11
        sub-port-id                   0
        description
        hostname
        ip-address                    192.168.1.157
        pri-utility-addr
        sec-utility-addr
        netmask                       255.255.0.0
        gateway                       192.168.1.1
        sec-gateway
        gw-heartbeat
            state                     disabled
            heartbeat                 0
            retry-count               0
            retry-timeout             1
            health-score              0
        dns-ip-primary                8.8.8.8
        dns-ip-backup1                8.8.4.4
        dns-ip-backup2
        dns-domain                    clearip.com
        dns-timeout                   11
        hip-ip-list
        ftp-address
        icmp-address
        snmp-address
        telnet-address
        ssh-address
        signaling-mtu

Realm configuration

The SBC is configured with two realms, CoreRealm and AccessRealm. They are mapped to the Core Network and Access Network, respectively. The Core Network includes trusted devices of the telephone service provider. The Access Network includes the devices outside the trusted network, customer devices, and provider devices.

Note: ClearIP can be treated as a trusted device in the Core Network or as a normal device in the Access Network. For the outbound scenario, ClearIP is treated as a device in the Access Network. You can either create a new realm or use an existing realm for ClearIP.

  • Sample realm configuration
    realm-config
        identifier                    CoreRealm
        description
        addr-prefix                   0.0.0.0
        network-interfaces            M10:0
        mm-in-realm                   disabled
        mm-in-network                 enabled
        mm-same-ip                    enabled
        mm-in-system                  enabled
        bw-cac-non-mm                 disabled
        msm-release                   disabled
        qos-enable                    enabled
        generate-UDP-checksum         disabled
        max-bandwidth                 0
        fallback-bandwidth            0
        max-priority-bandwidth        0
        max-latency                   0
        max-jitter                    0
        max-packet-loss               0
        observ-window-size            0
        parent-realm
        dns-realm
        media-policy
        media-sec-policy
        srtp-msm-passthrough          disabled
        in-translationid
        out-translationid
        in-manipulationid
        out-manipulationid
        manipulation-string
        manipulation-pattern
        class-profile
        average-rate-limit            0
        access-control-trust-level    none
        invalid-signal-threshold      0
        maximum-signal-threshold      0
        untrusted-signal-threshold    0
        nat-trust-threshold           0
        deny-period                   30
        cac-failure-threshold         0
        untrust-cac-failure-threshold 0
        ext-policy-svr
        diam-e2-address-realm
        symmetric-latching            disabled
        pai-strip                     disabled
        trunk-context
        early-media-allow
        enforcement-profile
        additional-prefixes
        restricted-latching           none
        restriction-mask              32
        accounting-enable             enabled
        user-cac-mode                 none
        user-cac-bandwidth            0
        user-cac-sessions             0
        icmp-detect-multiplier        0
        icmp-advertisement-interval   0
        icmp-target-ip
        monthly-minutes               0
        net-management-control        disabled
        delay-media-update            disabled
        refer-call-transfer           disabled
        refer-notify-provisional      none
        dyn-refer-term                disabled
        codec-policy
        codec-manip-in-realm          disabled
        constraint-name
        call-recording-server-id
        xnq-state xnq-unknown
        hairpin-id                    0
        stun-enable                   disabled
        stun-server-ip                0.0.0.0
        stun-server-port              3478
        stun-changed-ip               0.0.0.0
        stun-changed-port             3479
        match-media-profiles
        qos-constraint
        sip-profile
        sip-isup-profile
        block-rtcp                    disabled
        hide-egress-media-update      disabled
        tcp-media-profile
        subscription-id-type          END_USER_NONE
    realm-config
        identifier                    AccessRealm
        description
        addr-prefix                   0.0.0.0
        network-interfaces            M11:0
        mm-in-realm                   disabled
        mm-in-network                 enabled
        mm-same-ip                    enabled
        mm-in-system                  enabled
        bw-cac-non-mm                 disabled
        msm-release                   disabled
        qos-enable                    disabled
        generate-UDP-checksum         disabled
        max-bandwidth                 0
        fallback-bandwidth            0
        max-priority-bandwidth        0
        max-latency                   0
        max-jitter                    0
        max-packet-loss               0
        observ-window-size            0
        parent-realm
        dns-realm
        media-policy
        media-sec-policy
        srtp-msm-passthrough          disabled
        in-translationid
        out-translationid
        in-manipulationid
        out-manipulationid
        manipulation-string
        manipulation-pattern
        class-profile
        average-rate-limit            0
        access-control-trust-level    none
        invalid-signal-threshold      0
        maximum-signal-threshold      0
        untrusted-signal-threshold    0
        nat-trust-threshold           0
        deny-period                   30
        cac-failure-threshold         0
        untrust-cac-failure-threshold 0
        ext-policy-svr
        diam-e2-address-realm
        symmetric-latching            disabled
        pai-strip                     disabled
        trunk-context
        early-media-allow
        enforcement-profile
        additional-prefixes
        restricted-latching           none
        restriction-mask              32
        accounting-enable             enabled
        user-cac-mode                 none
        user-cac-bandwidth            0
        user-cac-sessions             0
        icmp-detect-multiplier        0
        icmp-advertisement-interval   0
        icmp-target-ip
        monthly-minutes               0
        net-management-control        disabled
        delay-media-update            disabled
        refer-call-transfer           disabled
        refer-notify-provisional      none
        dyn-refer-term                disabled
        codec-policy
        codec-manip-in-realm          disabled
        constraint-name
        call-recording-server-id
        xnq-state                     xnq-unknown
        hairpin-id                    0
        stun-enable                   disabled
        stun-server-ip                0.0.0.0
        stun-server-port              3478
        stun-changed-ip               0.0.0.0
        stun-changed-port             3479
        match-media-profiles
        qos-constraint
        sip-profile
        sip-isup-profile
        block-rtcp                    disabled
        hide-egress-media-update      disabled
        tcp-media-profile
        subscription-id-type          END_USER_NONE

3. Media configuration

The SBC should be configured to bypass media traffic between the SBC and ClearIP. Call audio should not be sent to ClearIP.

4. Outbound call scenarios

After an outbound call has been processed by ClearIP, ClearIP responds in one of three ways:

  1. No fraud detected
  2. Fraud detected
  3. Diverted

These call flows are described below.

No fraud detected

No fraud detected
  1. The CFS sends a call to the SBC core realm (a)
  2. The SBC forwards the call to ClearIP (b, c)
  3. ClearIP returns a SIP 404 if no fraud detected and no Identity header returned. If STIR/SHAKEN authentication is requested, ClearIP returns an Identity header in a SIP 302 (d).
  4. If the Identity header is returned, then the SBC should copy the Identity header into the outgoing SIP Invite using the header manipulation rules provided in the Appendix.
  5. SBC tries to forward the call to the Destination, the original target device (e)

Fraud detected

Fraud detected
  1. The CFS sends a call to the SBC core realm (a)
  2. The SBC forwards the call to ClearIP (b, c)
  3. ClearIP returns a SIP 603 (d)
  4. The SBC drops the call (e, f)

Diverted

Diverted
  1. The CFS sends a call to the SBC core realm (a)
  2. The SBC forwards the call to ClearIP (b, c)
  3. ClearIP returns a SIP 302 with the destination of the diversion device (d)
  4. SBC tries to forward the call to the diversion device (e)

5. SBC configuration

This section provides details on the SBC configuration settings for operation with ClearIP for outbound call scenarios.

High-level description

  1. The basic idea is to insert ClearIP into the normal configuration.
  2. The SBC should be configured to perform hunting (route advance) if ClearIP returns a SIP 404. The call routing policy rule for this part should be:
    1. Try ClearIP first
    2. Try other destinations
  3. By default, the SBC will perform hunting when it receives SIP 404 messages.
  4. The SBC should drop the call if ClearIP returns a SIP 603. This is the default behavior of the SBC, so no configuration should be needed.

The session agent for ClearIP should be configured to handle SIP redirect messages.

Instructions

A. Configure the AccessRealm SIP interface to use TCP

Important configuration items:

1.transport-protocolTCP
2.trans-expire5

ClearIP only supports TCP and TLS, so the SIP interface must be configured to support TCP. Trans-expire should be configured to allow the SBC to quickly fail a call attempt. This is useful if ClearIP is unavailable and the SBC timeout for establishing TCP connection is long.

  • Sample SIP interface configuration
    sip-interface
        state                         enabled
        realm-id                      AccessRealm
        description
        sip-port
            address                   YOUR_PUBLIC_IP_HERE
            port                      5060
            transport-protocol        TCP
            tls-profile
            multi-home-addrs
            allow-anonymous           all
            ims-aka-profile
        carriers
        trans-expire                  5
        initial-inv-trans-expire      0
        invite-expire                 0
        max-redirect-contacts         0
        proxy-mode
        redirect-action
        contact-mode                  none
        nat-traversal                 none
        nat-interval                  30
        tcp-nat-interval              90
        registration-caching          disabled
        min-reg-expire                300
        registration-interval         3600
        route-to-registrar            disabled
        secured-network               disabled
        teluri-scheme                 disabled
        uri-fqdn-domain
        trust-mode                    all
        max-nat-interval              3600
        nat-int-increment             10
        nat-test-increment            30
        sip-dynamic-hnt               disabled
        stop-recurse                  401,407
        port-map-start                0
        port-map-end                  0
        in-manipulationid
        out-manipulationid
        manipulation-string
        manipulation-pattern
        sip-ims-feature               disabled
        subscribe-reg-event           disabled
        operator-identifier
        anonymous-priority            none
        max-incoming-conns            0
        per-src-ip-max-incoming-conns 0
        inactive-conn-timeout         0
        untrusted-conn-timeout        0
        network-id
        ext-policy-server
        default-location-string
        charging-vector-mode          pass
        charging-function-address-mode pass
        ccf-address
        ecf-address
        term-tgrp-mode none
        implicit-service-route        disabled
        rfc2833-payload               101
        rfc2833-mode                  transparent
        constraint-name
        response-map
        local-response-map
        ims-aka-feature               disabled
        enforcement-profile
        route-unauthorized-calls
        tcp-keepalive none
        add-sdp-invite disabled
        add-sdp-profiles
        sip-profile
        sip-isup-profile
        tcp-conn-dereg                0
        register-keep-alive           none
        kpml-interworking             disabled
        tunnel-name
        msrp-delay-egress-bye         disabled
        send-380-response
        session-timer-profile

B. Configure ClearIP (sip.clearip.com) as a session agent

Important configuration items:

1.hostnamesip.clearip.com
2.port5060
3.transport-methodDynamicTCP
4.redirect-actionRecurse
5.ping-methodOPTIONS
6.ping-interval10
7.ping-send-modekeep-alive
8.ping-all-addressesenabled

ClearIP’s FQDN (Fully Qualified Domain Name), port, and transport protocol must be configured. The redirect action must be configured as recurse to allow the SBC to handle SIP redirect messages directly. Ping options should be configured to allow the SBC to detect ClearIP status instead of waiting for a TCP connection issue timeout.

  • Sample session agent configuration
    session-agent
        hostname                      sip.clearip.com
        ip-address
        port                          5060
        state                         enabled
        app-protocol                  SIP
        app-type
        transport-method              DynamicTCP
        realm-id                      AccessRealm
        egress-realm-id
        description
        carriers
        allow-next-hop-lp             enabled
        constraints                   disabled
        max-sessions                  0
        max-inbound-sessions          0
        max-outbound-sessions         0
        max-burst-rate                0
        max-inbound-burst-rate        0
        max-outbound-burst-rate       0
        max-sustain-rate              0
        max-inbound-sustain-rate      0
        max-outbound-sustain-rate     0
        min-seizures                  5
        min-asr                       0
        time-to-resume                0
        ttr-no-response               0
        in-service-period             0
        burst-rate-window             0
        sustain-rate-window           0
        req-uri-carrier-mode          None
        proxy-mode
        redirect-action               Recurse
        loose-routing                 enabled
        send-media-session            enabled
        response-map
        ping-method                   OPTIONS
        ping-interval                 10
        ping-send-mode                keep-alive
        ping-all-addresses            enabled
        ping-in-service-response-codes
        out-service-response-codes
        load-balance-dns-query        hunt
        media-profiles
        in-translationid
        out-translationid
        trust-me                      disabled
        request-uri-headers
        stop-recurse
        local-response-map
        ping-to-user-part
        ping-from-user-part
        li-trust-me                   disabled
        in-manipulationid
        out-manipulationid
        manipulation-string
        manipulation-pattern
        p-asserted-id
        trunk-group
        max-register-sustain-rate     0
        early-media-allow
        invalidate-registrations      disabled
        rfc2833-mode                  none
        rfc2833-payload               0
        codec-policy
        enforcement-profile
        refer-call-transfer           disabled
        refer-notify-provisional      none
        reuse-connections             NONE
        tcp-keepalive                 none
        tcp-reconn-interval           0
        max-register-burst-rate       0
        register-burst-window         0
        sip-profile
        sip-isup-profile
        kpml-interworking             inherit
    

Important notes:

  1. Using TLS instead of TCP is optional. If TLS is desired, then the port should be set to 5061.
  2. Do not configure the sip.clearip.com session agent with a static IP address. The IP addresses for ClearIP will change for load balancing and maintenance. Using a static IP address for ClearIP will cause a service interruption. Use hostname sip.clearip.com instead.
  3. ClearIP does not respond to UDP or ICMP (ping) messages.

C. Configure the destination (dest.carrier.com) session agent as the original target device

  • Sample destination session agent configuration
    session-agent
        hostname                      dest.carrier.com
        ip-address                    192.168.1.19
        port                          5060
        state                         enabled
        app-protocol                  SIP
        app-type
        transport-method              UDP
        realm-id                      AccessRealm
        egress-realm-id
        description
        carriers
        allow-next-hop-lp             enabled
        constraints                   disabled
        max-sessions                  0
        max-inbound-sessions          0
        max-outbound-sessions         0
        max-burst-rate                0
        max-inbound-burst-rate        0
        max-outbound-burst-rate       0
        max-sustain-rate              0
        max-inbound-sustain-rate      0
        max-outbound-sustain-rate     0
        min-seizures                  5
        min-asr                       0
        time-to-resume                0
        ttr-no-response               0
        in-service-period             0
        burst-rate-window             0
        sustain-rate-window           0
        req-uri-carrier-mode          None
        proxy-mode
        redirect-action
        loose-routing                 enabled
        send-media-session            enabled
        response-map
        ping-method
        ping-interval                 0
        ping-send-mode                keep-alive
        ping-all-addresses            disabled
        ping-in-service-response-codes
        out-service-response-codes
        load-balance-dns-query        hunt
        media-profiles
        in-translationid
        out-translationid
        trust-me                      disabled
        request-uri-headers
        stop-recurse
        local-response-map
        ping-to-user-part
        ping-from-user-part
        li-trust-me                   disabled
        in-manipulationid
        out-manipulationid
        manipulation-string
        manipulation-pattern
        p-asserted-id
        trunk-group
        max-register-sustain-rate     0
        early-media-allow
        invalidate-registrations      disabled
        rfc2833-mode                  none
        rfc2833-payload               0
        codec-policy
        enforcement-profile
        refer-call-transfer           disabled
        refer-notify-provisional      none
        reuse-connections             NONE
        tcp-keepalive                 none
        tcp-reconn-interval           0
        max-register-burst-rate       0
        register-burst-window         0
        sip-profile
        sip-isup-profile
        kpml-interworking inherit

D. Set the ClearIP session agent as the first enabled destination in the existing local policy

  • Sample local policy configuration
    local-policy
        from-address
                                      *
        to-address
                                      *
        source-realm
                                      CoreRealm
        description
        activate-time N/A
        deactivate-time N/A
        state enabled
        policy-priority none
        policy-attribute
        next-hop sip.clearip.com
        realm AccessRealm
        action none
        terminate-recursion disabled
        carrier
        start-time 0000
        end-time 2400
        days-of-week U-S
        cost 0
        app-protocol
        state enabled
        methods
        media-profiles
        lookup single
        next-key
        eloc-str-lkup disabled
        eloc-str-match
        policy-attribute
        next-hop dest.carrier.com
        realm AccessRealm
        action none
        terminate-recursion disabled
        carrier
        start-time 0000
        end-time 2400
        days-of-week U-S
        cost 0
        app-protocol
        state enabled
        methods
        media-profiles
        lookup single
        next-key
        eloc-str-lkup disabled
        eloc-str-match

6. Sending SIP INVITEs to ClearIP

If the above configurations have been implemented successfully, then the SBC should be able to send a SIP INVITE to ClearIP.

The following is an example SIP INVITE message with the minimum number of SIP headers required by ClearIP. ClearIP will accept a SIP INVITE in any format, with no limit on additional headers and the SDP (Session Description Protocol) information.

INVITE sip:18001234567@sip.clearip.com:5060 SIP/2.0
Via: SIP/2.0/TCP sip.clearip.com:5060
From: <sip:14045266060@5.6.7.8:5060>;tag=123456789
To: sip:18001234567@1.2.3.4:5060
Call-ID: 1-12345@5.6.7.8
CSeq: 1 INVITE
Max-Forwards: 70
Content-Length: 0

ClearIP should respond to the SIP Invite with a SIP 403 Forbidden until the SBC’s IP address has been defined in the ClearIP user interface. After the SBC’s IP address has been added to ClearIP, then ClearIP can respond to the SIP INVITE with a SIP 404, SIP 603, or SIP 302.

Appendix

CFS local routing policies

This documentation mentions Call Feature Server local routing policies in previous sections but does not show them explicitly in any of the above SBC configurations. Call Feature Server local routing policies play a very important role in the SBC outbound call scenario configuration. This section discusses the CFS local routing policies and how they influence the SBC configuration.

In outbound call scenarios, the Call Feature Server performs routing look up tasks. It sends SIP INVITE messages containing the routing information of the destinations to the SBC. Normally, there are three ways to do it:

  1. Send SIP INVITE messages to different SBC core network interfaces for different carriers/destinations.
  2. Send SIP INVITE messages to a single SBC core network interface. The SIP INVITE messages contain the routing information of the destinations, such as trunk group ID.
  3. Send SIP INVITE messages to the SBC working as an outbound proxy. The SIP INVITE messages directly contain the IP/FQDN of the destinations in the Request-URI.

The first routing approach is the simplest one. The routing logic on the SBC is clear and easy to implement. This documentation uses this approach. One thing that was not mentioned in previous sections is that for this approach, multiple core realms/sub-realms should be configured. Each core realm/sub-realm maps to one set of carriers/destinations. When the CFS sends a SIP INVITE to a certain SBC core realm, the SBC local policy forwards it to a certain set of destinations.

The second routing approach is also commonly used although it is a bit more complicated. The SBC must be configured to route the calls based on additional parameters such as the trunk group ID. The SBC has internal mechanisms to route calls based on the trunk group ID, which is not discussed in this documentation. If more general parameters are used for routing purpose, the SBC configuration will be more complicated.

The third approach is only supported by some call feature servers. It is also difficult for the SBC to insert ClearIP into its local policies. This documentation does not provide any details about this approach.

Oracle Acme Packet SBC configuration for ClearIP outbound scenarios