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Overview

Use the SIP Filter Profile to associate one ore more SIP headers with the profile to control header parsing for a particular trunk group. Depending on the filter settings of each of the SIP headers in the SIP Filter Profile, the SBC either relays the SIP messages without parsing the header, or parses the message headers.

For every SIP message associated with the ingress leg of the call, the SBC first checks the SIP Filter Profile for the filter setting of the SIP header. If the SIP Filter Profile indicates that a particular SIP header needs filtering, the SBC stores it without parsing.  

The SIP header of the egress leg is populated on the basis of the configuration in the IP Signaling Profile and the Transparency Profile. In the egress leg of a call, the transparency bit mask is set to identify the headers that are transparently passed. If the transparency settings of all unknown headers in the IP Signaling Profile is enabled, all the stored headers (including the ones filtered in the ingress leg), is copied to the SIP header of the egress leg.

If the Transparency Profile attached with the Egress Trunk Group indicates that specific headers are allowed to pass transparently, and those headers are present as filtered headers, they are individually copied to the SIP header of the egress leg. In this case, the transparency bits are enabled, either by the IP Signaling Profile or through the flexible header transparency. For more information on the SIP Filter Profile, Transparency Profile and SIP header transparency, refer to Transparency Profile and SBC SIP Transparency Implementation Guide respectively.

Note

A SIP Filter Profile is not used for the egress leg of a call.

Note

A filtered header of a call in a Gateway-Gateway (GW-GW) scenario is not passed to the egress gateway if that header is known to the egress gateway, even if the "unknown" header transparency is enabled.

For example, the P-Asserted-Identity (PAI) header is not passed transparently if the following events occur simultaneously:

  • the PAI is filtered on the ingress

  • the "unknown" header transparency is enabled on the egress gateway
  • the PAI header is known to the egress gateway.
 
To pass the PAI header transparently on the egress gateway, enable transparency for the PAI header through a SIP Filter Profile.

Command Syntax

Use following CLI syntax to configure a SIP Filter Profile.

% set profiles signaling sipFilterProfile <sipFilterProfileName> header <disabled | enabled>

 

Command Parameters

Table : SIP Filter Profile Parameters

ParameterLength/RangeDescription
sipFilterProfile1-23 characters

<profile name> – The name of the SIP Filter Profile created, and optionally attached to a SIP Trunk Group. In the default SIP Filter Profile, the transparency settings of all permissible headers is set to disabled.

headerN/A

<header name> – The name of the header to attach to this SIP Filter Profile. For a list of permissible headers, refer to Supported SIP Headers.

    • disabled (default) – Disable SIP header filtering of this header for this SIP Filter Profile.
    • enabled – Enable SIP header filtering of this header for this SIP Filter Profile.

If a header is known and the filter setting for the header is set to disabled (default), the header is parsed by the SBC. If a parsing error occurs, the SBC terminates the call. However, if the filter setting for a known header is set to enabled, the SBC does not parse the header even if parsing for the header is supported by the SBC. Additionally, all known filtered headers and unknown headers can be transparently relayed without parsing if the unknown header transparency is enabled in IP Signaling Profile.

Note: If sipFilterProfile is used for Allow, Require and Supported headers, transparency is not allowed using sipParamFilterProfile.

To attach a SIP Filter Profile to a trunk group, use the following CLI syntax. For additional details, refer to SIP Trunk Group - Signaling - CLI.

% set addressContext <addressContextName> zone <zoneName> sipTrunkGroup <sipTrunkGroupName> signaling sipFilterProfile <sipFilterProfileName>