L7 Dynamic Rule
explains how the dynamic rule can be extended to support L7 capabilities.
Flow-Description AVP that is already part of Charging-Rule-Definition AVP is
used like a "Routing Rule". The packets matching to the Flow-Information will
be sent to the analyzer mentioned in L7-Protocol-Name AVP.
When an L7 dynamic
rule is received with Flow-Description AVP, the Flow-Description AVP is used
for routing the packets matching to the protocol specified through
L7-Application-Description AVP. The gateway internally creates a route using
the Flow-Description AVP from the dynamic rule to the protocol mentioned in the
L7-Protocol-Name AVP. Hence, all flows matching the specified criteria are sent
for protocol analysis.
Flow-Description AVP is not received with the dynamic rule, default routes are
used to enable the corresponding protocol routing. The well-known port numbers
are used to enable the protocol analyzer. Since only HTTP protocol is
supported, port 80 is used for enabling the protocol.
For rule matching,
both the criteria associated with Flow-Description and
L7-Application-Description AVPs are used. If Flow-Description AVP is not
received, only the criteria associated with L7-Application-Description AVP is
For dynamic rule
modification, the L7 dynamic rule is installed again with a new set of values
for L7-Application-Description AVP. The old values are overridden with the new
values and added to the dynamic rule. For removal of L7 dynamic rules,
Charging-Rule-Remove AVP is used.
The following are
some additional points related to handling of L7 dynamic PCC rules from PCRF.
L7 dynamic rule
binding is similar to the normal L3 dynamic rule.
If L7 rule does
not contain TFT filter then rule will be bound to the bearer matching QoS.
Recovery (SR)/Inter-Chassis Session Recover (ICSR) will be supported for L7
In releases prior to
20, when invalid values are sent for Rule-Condition and Rule-Action AVPs from
PCRF for a dynamic rule, gateway accepts and installs the dynamic rule. In 20
and later releases, the gateway rejects the dynamic rule with invalid
condition-action, and reports the failure with the cause "GW/PCEF_MALFUNCTION
(4) ". The same behavior is observed even when the AVP fields are empty.