ltm rule namespace GTP

iRule(1)					  BIG-IP TMSH Manual					     iRule(1)

GTP
       Namespace GTP

DESCRIPTION
       iRules commands that are specifically designed to query for or manipulate GTP (GPRS Tunneling Protocol)
       information, including commands to access the parsed fields such as TunnelID, GGSN address (APN), MSISDN, and
       IMSI.

       A few use cases for such information:
	 * Information from the parsed fields may be used to LB GTP traffic to pool members
	 * Persistence can be enabled via iRules using specific GTP info
	 * iRules to allow more control over GTP specific traffic

       Parsing - Within this command namespace APIs are provided to:
	    * Parse the message from given blob.
	    * Access GTP header fields.
	    * Access Payload in case of G-PDU.
	    * Access extension headers.
	    * Walk the list of extension headers.
	    * Access an extension header of a given type.
	    * Access Information Elements (IEs)
	    * And much more...	Creating - APIs are provided to help create a message.
	    * A create message is called with "version" & "type".
		 + Header fields other than "version", "type" & "length" can be added/updated/removed.
		      o The header fields that are mandatory per specifications canXt be removed, but could be
       zeroed.
	    * The length of the message is computed dynamically as updates happen to the message.
	    * For Version 1, the extension headers can be added/updated/removed.
	    * IEs can be added/updated/removed to message or another IE (grouped IE only).

       Associated Events
	    * GTP_GPDU_EGRESS - Fired for a message that has GTP message-type = 255 on the connection that
       forwards/egresses the message.
	    * GTP_GPDU_INGRESS - Fired for a message that has GTP message-type = 255 on the the connection that
       accepted the message.
	    * GTP_PRIME_EGRESS - Fired only for GTP prime messages for revision 1 on the connection that
       forwards/egresses the message.
	    * GTP_PRIME_INGRESS - Fired only for GTP prime messages for revision 1 on the connection that accepted
       the message.
	    * GTP_SIGNALLING_EGRESS - Fired for any GTP-message except G-PDU on the connection that forwards/egresses
       the message.
	    * GTP_SIGNALLING_INGRESS - Fired for any GTP-message except G-PDU on the connection that accepted the
       message

HINTS
SEE ALSO
BIG-IP						      2020-06-23					     iRule(1)