Unknown Header

An Unknown header is a SIP header that is not included in this list of supported headers. An example of the header is shown below:

MYEXP: scooby, doo, goo, foo

The device's Message Manipulation feature supports up to three occurrences of a given unknown header in a single message. If there are more than three of the same header, the device removes the extras.

The header properties are shown in the following table:

Header Level Action

Add

Delete

Modify

List Entries

Operations Supported

Yes

Yes

Yes

3

Keyword

Sub Types

Attributes

N/A

N/A

N/A

Below are header manipulation examples:

Example 1

Rule:

Add a custom header to all messages:

■ Message Type: Any
■ Action Subject: header.myExp
■ Action Type: Add
■ Action Value: 'scooby, doo, goo, foo'

Result:

 
myExp: scooby, doo, goo, foo

Example 2

Rule:

Create a new header called "media", whose value is a concatenation of the time in the Session-Expires header, followed by "000", followed by ";refresher=", followed by "1" or "2", depending on whether the refresher parameter in the Session-Expires header has the value 'UAC' or 'UAS':

■ Message Type: Any
■ Action Subject:header.media
■ Action Type: Add
■ Action Value: header.Session-Expires.time + '000' + ';refresher=' + header.Session-Expires.Refresher

Result:

 
media: 3600000;refresher=1

Example 3

Rule:

Create lists of Unknown headers:

■ Message Type: Invite
■ Action Subject: header.myExp.1
■ Action Type: Add
■ Action Value: 'scooby, doo, goo, foo'

Result:

 
myExp: scooby, doo, goo, foo

Example 4

Rule:

Remove the SIP header 'colour' from INVITE messages:

■ Message Type: Invite
■ Action Subject: header.colour
■ Action Type: Remove

Result:

The colour header is removed.