Cisco P-GW supports
ICSR/SR check pointing at session level. The Flow Recovery feature was
introduced to support flow checkpoint for ECS rules.
This feature adds
Flow Checkpoint support for ADC rules after ICSR/SR switchover. Flows of a rule
can be recovered if the rule is made eligible. To make any rule eligible for
checkpointing or recovery, the rule must be configured in the service scheme
framework and identified based on rulename. Any type of rule can be eligible
for checkpointing irrespective of the rule definition or protocol type. The
rule type can be static/predefined, group-of-ruledef, dynamic, or ADC rule.
When this feature is
implemented, the following things are avoided:
-
Default rule
being matched post recovery or ICSR switchover.
-
Flow charging
when they are zero rated or not charged.
-
Different or
incorrect policy being applied to the data.
Behavior
Changes
Previous Behavior 1:
For configuring multiple rules for flow recovery, a single trigger
condition was sufficient as it was possible to add all eligible rules under it
along with the delay. If a flow matches any of the configured eligible rules,
P-GW started checkpointing the flow after the configured period of delay.
Example:
Rule rule01, rule02, and rule03 are eligible for flow recovery.
Flow should be checkpointed after 60 sec of flow creation.
trigger-condition tc1
rule-name = rule01
rule-name = rule02
rule-name = rule03
delay = 60
#exit
The above
configuration enabled P-GW to checkpoint flows matching either rule01, rule02,
or rule03 after a delay of 60 seconds.
New Behavior 1:
With this feature, there is a change in the way flow recovery is
configured on the chassis. A new CLI command
multi-line-or all-lines under trigger condition.
Because of this delay cannot be configured along with multiple rules in same
trigger condition. If there is a need to configure delay, then you must create
multiple trigger condition (one for each rule).
Example with new
configuration:
trigger-condition tc1
rule-name = rule01
delay = 60
#exit
trigger-condition tc2
rule-name = rule02
delay = 60
#exit
trigger-condition tc3
rule-name = rule03
delay = 60
#exit
The above
configuration enables P-GW to checkpoint flows matching either rule01, rule02,
or rule03 after a delay of 60 seconds.
Configuration for
multiple rules without delay:
trigger-condition tc1
rule-name = rule01
rule-name = rule02
rule-name = rule03
multi-line-or all-lines
#exit
Previous Behavior 2:
ULI was not sent with "successful_resource" allocation CCR-U, if
there is no change in the ULI.
New Behavior 2:
ULI is sent with "successful_resource" allocation CCR-U, even if
there no change in the ULI. Old value of ULI is encoded and sent.
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