SIP Profiles

A profile allows you to create a specific set of characteristics different from the standard SBC defaults. When defining a new instance of one of these objects, simply use the profile to quickly customize the values. A brief summary of SIP profiles is provided below.

SIP ARS Profile

To achieve efficient device failover to the backup/secondary Application Server, the SBC uses the Address Reachability Service (ARS) to determine if a server is reachable, providing the ability to "blacklist" a server IP address if it is found to be unreachable, as well as the ability to remove the server from the blacklisted state. ARS profiles can be created to configure blacklisting and recovery algorithm variants.

These ARS profiles can be assigned to the services section of a SIP trunk group to enforce the blacklisting and recovery of any SIP peer(s) associated with the trunk group. If no recovery algorithm is specified when configuring a SIP ARS profile, the recovery algorithm default values are used as indicated below:

• recoveryAlgProbeDuration: 1 second
• recoveryAlgProbeInterval: 1 second
• recoveryAlgProbeMethod: sip-options
• recoveryAlgProbeNumResponses: 1
• recoveryAlgTimerDuration: 1 second
• recoveryAlgorithm: probe

Refer to the following pages for configuration details:

• EMA: Service Profiles - SIP ARS Profile
• CLI: SIP ARS Profile - CLI

SIP Call Admission Control Profile

The SBC provides call and registration admission control for SIP calls and SIP registrations at the zone level, SIP trunk group level, and SIP endpoint level. For more information refer to Call Admission Controls.

Refer to the following pages for configuration details:

• EMA: Profiles - SIP CAC Profile
• CLI: SIP CAC Profile - CLI

SIP/CPC Cause Code Mapping Profiles

The Cause Map Profile, SIP-to-CPC and CPC-to-SIP mappings provide customized tables on the SBC to map cause codes between SIP and Q.850 cause codes. Previously, these mappings were hard coded in the SBC. The custom mappings can be selected on a per route basis on egress trunks and ingress trunks on the SBC.

The following IPSP configurations are added to PSX under SIP Cause Mapping section to specify the Cause Code Mapping profile name.

• Internal to SIP Cause Mapping Profile Name
• SIP to Internal Cause Mapping Profile Name

The PSX returns the Cause Code profile name in the POL responses. The SBC uses the Cause Code profile specified by PSX. If PSX fails to provide the Cause Code profile, the SBC uses the local Cause Code Mapping profile configured on the SIP Trunk Group.

The SBC applies the Cause Code Mapping profile in the following order:

1. If a policy response contains a profile name and a locally configured profile uses the same name, the SBC applies the same name.

2. If a policy response does not contain a profile name or if the profile name does not match with any local profile, the SBC applies the SIP Trunk Group created local profile name (if created).

3. The SBC applies a default profile name if none of the above two cases match.

The SBC supports SIP Cause Code Mapping for CPC to SIP for trunk groups regardless of the signaling zone.

The PSX sends the SIP_USED_IN_CORE flag with the policy response to the egress SBC. If the egress SBC receives the SIP_USED_IN_CORE flag and the ingress zone of the egress SBC is in the default signaling zone, the egress SBC does not allow SIP Cause Code Mapping for CPC to SIP because the scenario is SIP In Core. If the PSX either is not present or does not enable the SIP_IN_CORE flag, then SIP Cause Code Mapping for CPC to SIP functions as if the SBC uses a non-default signaling zone. The following figure illustrates the SIP In Core call flow.

SIP in Core Call Flow

When the call flow uses a single SBC, the PSX always disables the SIP_IN_CORE flag and the SIP Cause Code Mapping for CPC to SIP occurs whether or not the SBC uses the default signaling zone.

The following figure illustrates the I-SBC call flow.

I-SBC Call Flow

Refer to the following pages for configuration details:

• EMA: Signaling Profiles - SIP Cause Code Mapping
• CLI: SIP/CPC Cause Code Mapping Profiles

SIP Emergency Call Profile

This object creates and configures an Emergency Call Profile for SIP calls used to host emergency call criteria. The emergency call classification methods are:

• Emergency Call Marking: The cpc-priority in P-Asserted Identities is present in the INVITE message, and the CPC parameter of the SIP EMERGENCY PROFILE is set to “priority”.
• Prefix Matching (up to three prefixes): At least one of the three emergency prefixes is configured in SIP EMERGENCY PROFILE and the R-URI header in the INVITE message matches one of the three emergency prefixes. The emergency prefix is an alphanumeric string that consists of numeric digits (phone number). For more information refer to Call Admission Controls.
• URN Prefix: Emergency prefix URN, for example “services:sos”.
• X-EMG Header: Use this flag to determine whether SIP X-EMG header should be accepted as an emergency call indicator.

Refer to the following pages for configuration details:

• EMA: Service Profiles - Emergency Call Profile
• CLI: Emergency Call Profile - CLI

SIP JIP Profile

The Jurisdiction Information Parameter (JIP) is a 6-digit field (NPA-NXX format) in an ISUP IAM message used to indicate the geographic location of the originating caller or switch. This information may be used in billing. 

The SBC supports sending JIP information in SIP-SIP, SIP-SIP-I and SIP-I to SIP scenarios. This capability is enabled/disabled through the SIP Jurisdiction Support option (sipJurisdictionSupport flag) set in the SIP trunk group, and specific processing details are controlled through the SIP JIP profile assigned to the trunk group.

When SIP Jurisdiction support is enabled, options in the SIP JIP profile assigned to the ingress SIP trunk group specify where to extract the SIP JIP value from in an incoming SIP INVITE message. The SBC can take the JIP value from the following parameters:

• rn parameter in the PAI header
• jip parameter in the PAI header
• rn parameter in the From header
• jip parameter in the P-DCS-Billing-Info header

Note that if a SIP JIP profile enables more than one possible source parameter, the SBC prioritizes them in the order shown above.

The SBC sends the JIP value it extracts to the external PSX. Based on its configuration, the PSX determines what JIP value should be sent out and returns this value to the SBC.

In the outgoing message, the SBC sends the JIP it received from the PSX in the parameter specified in the SIP JIP profile assigned to the egress SIP trunk group. The parameter options are the same as the source choices:

• rn parameter in the PAI header
• jip parameter in the PAI header
• rn parameter in the From header
• jip parameter in the P-DCS-Billing-Info header

For cases when the JIP value is sent in a P-DCS-Billing-Info header, the SIP trunk group also includes a parameter (feidForPDCS) in which you can specify a Financial-Entity-ID (FEID) to be sent out in the egress PDCS-Billing-Info header. An FEID consists of hexadecimal string of up to 16 characters followed by a domain name. 

The SBC records JIP-related details in the Call Detail Record.

Refer to the following pages for configuration details:

• EMA: Service Profiles - SIP JIP Profile
  
• CLI: SIP JIP Profile - CLI
  

SIP OCSP Profile

The Online Certificate Status Protocol (OCSP) enables SBC applications to determine the revocation status of a given certificate. OCSP is used to satisfy some of the operational requirements of providing timely revocation information.

When a peer sends certificates, an OCSP client (e.g. SIPFE) issues a status request to an OCSP responder and suspends acceptance of the certificates in question until the responder provides a response. The OCSP client needs the address/URL of the OCSP responder, the certificate to be checked, and the certificate issuer’s certificate. The OCSP URL can be FQDN or IPv4 address plus port number.

The SBC supports adding OCSP configuration to an existing/new TLS profile, and performing automatic OCSP checking in OpenSSL library without making substantial changes to OCSP clients (SIPFE, etc.). The OCSP clients may be involved when OCSP checking returns errors. The user may create up to four OCSP profiles per system as described in "Key Concepts" section below.

The SBC can act in TLS server role as well as TLS client role.

• As a TLS server with Client Authentication enabled, the SBC checks OCSP status when the TLS client sends its certificate chain to the SBC. Upon receiving Certificate Verify from client, theSBC performs OCSP status checking for each certificate in the chain after validating signature, expiration time, etc. for each certificate in the chain.
• When acting as a TLS client, SBC checks OCSP status when the peer TLS server sends its certificate chain to the SBC. The SBC then performs OCSP status checking for each certificate in the chain.

Key Concepts

The user may create up to four OCSP profiles per system, each specifying the OCSP capabilities and protocol parameters applying to one or more TLS connections that use the profile (a SIP/TLS connection may reference an OCSP profile in its assigned TLS profile). The OCSP profile is referenced by the existing TLS profile.

• OCSP capability
  • enabled
  • disabled (default)
• Default responder URI (default: blank):
  
  • IPv4 address and port number, or
  • FQDN
• AIA override:
  • enabled - Forces the use of configured Default responder for OCSP validation regardless of whether or not the certificate being validated references a responder by AIA.
  • disabled (default) - The responder referenced via AIA by the certificate being validated is used, or the Default responder as configured is used only if the AIA is not available.
• OCSP Stapling
  
  • disabled (default)
  • enabled
• OCSP response waiting time - If the corresponding OCSP response does not return before the time expires after sending an OCSP request, the response is considered unavailable.
  
  • Range: 1-16 seconds. Default: 2.
• OCSP Response Caching Timer
  • Range: 1-30 days. Default: 1.

When configuring an OCSP profile, be aware that you may delete a given OCSP profile when it is not referenced by any TLS connections.

When OCSP is enabled for a TLS connection, every individual certificate in the chain presented by the peer device during the establishment of the connection is validated against an OCSP responder for its revocation status.

When the SBC is upgraded from a release which already supports OCSP, all the parameter values of existing OCSP profiles are retained after the upgrade completes.

OCSP Stapling

SBC as a Server or Client

The SBC that acts as a server checks if the OCSP response is available in the OCSP cache before the SBC queries the OCSP server. If the OCSP response is available in the OCSP cache, the SBC uses that OCSP response to send the response as a certificate status message. If the OCSP response is not available in the OCSP cache, the SBC queries the OCSP server to receive the OCSP response.

If the ingress peer sends a ClientHello with the "status_request: OCSP" status request extension to the SBC (as a server) and you

• enable the ocspStapling flag in the ingress OCSP profile, the SBC sends an OCSP request to the OCSP responder and receives the OCSP response. The SBC stores the OCSP response in the OCSP cache before it sends the OCSP response as a certificate status message to the ingress peer.

  Note

  The SBC does not send a certificate status message to the client when the SBC receives a failure response from the OCSP responder. The client must use another mechanism to verify the validity of the server certificate.

• disable the ocspStapling flag in the ingress OCSP profile, the SBC does not send a certificate status message to the ingress peer. The SBC ignores the OCSP status extension.

When the SBC enables mutual authentication and receives a ClientHello with the "status_request: OCSP" status request extension, the SBC sends the client the OCSP response as a certificate status message.

If the ingress peer sends a ClientHello with the "status_request: OCSP" status request extension, and both mutual authentication and the ocspStapling flag are enabled in the ingress OCSP profile, the SBC sends an OCSP request to the OCSP responder and receives the OCSP response. The SBC then sends the OCSP response as a certificate status message to the ingress peer.

When the SBC acts as a client and you enable the ocspStapling flag in the egress OCSP profile, the SBC sends a ClientHello with the "status_request: OCSP" status request extension to the egress TLS peer. When the SBC acts as a client and you disable the ocspStapling flag in the egress OCSP profile, the SBC does not send a ClientHello with the "status_request: OCSP" status request extension to the egress TLS peer.

When the SBC acts as a client, the SBC checks the certificate status message received from the server for the validity of the server certificate. If the server certificate status is

• good, the SBC establishes a TLS connection with the egress peer.
• revoked, the SBC does not establish a TLS connection with the egress peer.
• unknown, the SBC establishes a TLS connection with the egress peer and logs a major log that indicates the status is unknown in the debug file.
  

The following figure illustrates the OCSP stapling call flow.

OCSP Stapling Call Flow

Linux DNS Client Support

Linux DNS client functionality is required for OpenSSL OCSP API to translate a FQDN to an IPv4 address. To populate the file with DNS server addresses, use following CLI commands.

% set addressContext default dnsGroup d1 type mgmt server dns1 ipAddress 10.11.12.13 state enabled
% set addressContext default dnsGroup d1 type mgmt server dns2 ipAddress 10.11.12.15 state enabled

Refer to the following pages for command details:

• EMA: Security Configuration - OCSP Profile
• CLI: OCSP Profile - CLI

SIP Security Profile

The SIP Security Profile feature defines the type and behavior of security mechanism to apply to the SBC acting as P-CSCF.

Refer to the following pages for command details:

• EMA:  Service Profiles - Sip Security Profile
• CLI: SIP Security Profile - CLI

Transparency Profile

The SBC supports flexible header transparency feature which allows a user to define a set of SIP header names using a configuration interface to the Transparency Profile (TP), and then assign that profile to a Trunk Group (TG). For example, if a header name is in the TP corresponding to the egress leg (respective to the message), it is passed through unmodified with its full content, including all parameters. This applies to all initial INVITE, REGISTER and mid-INVITE initiated dialog requests and responses (excluding mid-dialog SUBSCRIBE requests and responses sent in the context of an existing dialog). Corresponding relay flags for other mid-dialog requests (e.g. INFO, MESSAGE, NOTIFY) must be enabled for this functionality to work.

If a header is not in the transparency configurable, existing “Unknown Header Transparency” and explicit header transparency flag semantics shall apply.

This feature allows you to add previously “unknown” headers to the TP making them “semi-known” to the system, as well as add “known” headers thus eliminating the need for IP Signaling Profile (IPSP) transparency control flags for those headers. An "unknown" header is defined as a header that, if present in an incoming SIP message, is parsed as a generic “unknown” header, but is treated as a “known” header with respect to transparency by allowing individual transparency control towards it.

If you configure a Contact header in the Transparency Profile, it is treated as full contact header transparency.

Support for known headers (with or without IPSP transparency flags) is available for INVITE, REGISTER and OOD messages. Support for selective unknown header transparency is available for INVITE, REGISTER messages.

The following message body headers cannot be used when configuring a Transparency Profile:

• Content-Encoding
• Mime-Version
• Content-Disposition

The SBC supports configuring up to 256 Transparency Profiles. By default, no headers are present in the Transparency Profile.

Refer to the following pages for command details:

• EMA: Service Profiles - Transparency Profile
• CLI: Transparency Profile - CLI