Require

An example of the header is shown below:

Require: 100rel

The header properties are shown in the following table:

Header Level Action	Add	Delete	Modify	List Entries
Operations Supported	Yes	Yes	Yes	N/A

Keyword	Sub Types	Attributes
Capabilities	SIPCapabilities Struct	Read/Write

Below are header manipulation examples:

Example 1	Rule:	Add a Require header to all messages: ■ Message Type: Any ■ Action Subject: header.require ■ Action Type: Add ■ Action Value: 'early-session,em,replaces'
	Result:	Require: em,replaces,early-session
Example 2	Rule:	If a Require header exists, then delete it: ■ Message Type: Invite ■ Condition: header.require exists ■ Action Subject: header.require ■ Action Type: Remove
	Result:	The Require header is deleted.
Example 3	Rule:	Set the early media options tag in the header: ■ Message Type: Any ■ Action Subject: header.require.capabilities.earlymedia ■ Action Type: Add ■ Action Value: 1
	Result:	Require: em,replaces,early-session, early-media
Example 4	Rule:	Set the privacy options tag in the Require header: ■ Message Type: Invite ■ Action Subject: header.require.capabilities.privacy ■ Action Type: Add ■ Action Value: 1
	Result:	Require: em,replaces,early-session, privacy