для Cisco Cisco Packet Data Gateway (PDG)
Diameter Overload Control
▀ Feature Description
▄ AAA Interface Administration and Reference, StarOS Release 19
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Feature Description
Overview
This feature is implemented to support Overload Control on Diameter interfaces such as Gx, S6b and SWm and also to
prevent network overload and outages. Whenever there is an overload condition at the Diameter Servers or DRA and
request times out, the clients (ePDG/P-GW) are typically unaware of the overload condition and attempt to send the
message on an alternate connection with the Diameter server causing some more traffic in the network. In order to
handle this overload condition effectively, a new vendor-specific Diameter Experimental Result-Code 5198
(DIAMETER_OVERLOAD_RETRY_NOT_ALLOWED_TO_ANY) is defined.
prevent network overload and outages. Whenever there is an overload condition at the Diameter Servers or DRA and
request times out, the clients (ePDG/P-GW) are typically unaware of the overload condition and attempt to send the
message on an alternate connection with the Diameter server causing some more traffic in the network. In order to
handle this overload condition effectively, a new vendor-specific Diameter Experimental Result-Code 5198
(DIAMETER_OVERLOAD_RETRY_NOT_ALLOWED_TO_ANY) is defined.
When the overloaded PCRF/DRA receives a message, it includes the result-code 5198 in the response message. On
receiving the experimental result-code, call is terminated based on the failure-handling configuration. If failure-handling
is configured as local-policy, then the call is continued with local-policy without retrying the secondary server.
receiving the experimental result-code, call is terminated based on the failure-handling configuration. If failure-handling
is configured as local-policy, then the call is continued with local-policy without retrying the secondary server.
In Releases prior to 19, no indication was available to P-GW and ePDG when the Diameter Server or the DRA is
overloaded. When a message sent to the primary link on Diameter is dropped or unanswered, P-GW/ePDG tried the
same message on the secondary peer and resulted in the overloading of Diameter Server.
overloaded. When a message sent to the primary link on Diameter is dropped or unanswered, P-GW/ePDG tried the
same message on the secondary peer and resulted in the overloading of Diameter Server.
In 19 and later releases, the following changes are implemented to support Overload Control on Gx interface:
A new vendor-specific Diameter Experimental Result-Code 5198
(DIAMETER_OVERLOAD_RETRY_NOT_ALLOWED_TO_ANY) is added to indicate the overload state of
PCRF.
PCRF.
When the failure handling template is not configured and if the Experimental Result-Code (5198) is received in
CCR-U, then the current call is terminated.
If the Assume Positive feature is configured, the call is continued without retrying the secondary server.
The default action for Experimental Result-Code error (5198) is retry and terminate. Retry and terminate will be
the failure handing action irrespective of the configured value.
New statistics are added to the output of
show ims-authorization policy-control statistics
command to display the number of times the Experimental Result-Code 5198 has been received. Separate
statistics are also introduced to display the message level information.
statistics are also introduced to display the message level information.
To support Overload Control on S6b and SWm interfaces, the following changes are implemented:
A new vendor-specific Diameter Experimental Result-Code 5198
(DIAMETER_OVERLOAD_RETRY_NOT_ALLOWED_TO_ANY) is added to indicate the overload state of
Diameter agent.
Diameter agent.
Failure handling template is introduced for S6b and SWm interfaces, and associated to AAA group
authentication.
The default action for Experimental Result-Code (5198) is retry and terminate. For Diabase error, the failure-
handling action will be retry and terminate irrespective of the configured value.
When the Experimental Result-Code (5198) is received and the
failure-handling
command is configured as
continue
, then call is continued without retrying the secondary server. The
continue
action is applicable
only to aaa-custom15 dictionary.
When the Result-Code (5198) is received in DEA/AAA request, the call is terminated without the Session
Terminate Request (STR) for S6b and SWm interfaces.