Configuring Nack Generation For Srp Checkpoint Messaging Failures; Enabling Nack Messaging From The Standby Chassis - Cisco ASR 5500 System Administration Manual

Configuring the Service Redundancy Protocol (SRP) Context
medium { auto | speed { 10 | 100 | 1000 } duplex { full | half } }
no shutdown
bind interface srp_if_name srp_ctxt_name
end

Configuring NACK Generation for SRP Checkpoint Messaging Failures

Enabling NACK Messaging from the Standby Chassis

Transport (TCP) level re-transmission is supported on the SRP link between ICSR chassis. SRP configuration
also supports optional application level checks to ensure checkpoints are received at the Standby chassis.
Failed attempts to receive and apply checkpoints send NACK messages to the Active chassis.
When this feature is enabled and the standby chassis sends a NACK in response to the receipt of a
micro-checkpoint (MC) that fails to be successfully applied, the standby chassis sends another NACK. The
standby chassis will send more NACKs (configurable, default = 3) within a 10-minute window if a
macro-checkpoint (FC) is not received. NACKs will continue to be sent and the 10-minute reset until an FC
is received and applied, or the configured number of max-responses is reached.
You can also specify the number of times a NACK is sent within the 10-minute window in response to a failed
MC or FC (Default = 3).
A nack keyword in the SRP Configuration mode checkpoint session command allows you to enable generation
of NACK messages in response to checkpoint message failures on a Standby ICSR chassis.
Important The nack keyword will only appear if a special ICSR optimization feature license has been purchased
and installed. Contact your Cisco account representative for assistance.
configure
context context_name
service-redundancy-protocol variable
checkpoint session nack { macro | micro } [ max-response number ]
no checkpoint session nack { macro | micro }
end
Notes:
• max-response is the number of times a NACK is sent within the 10-minute window in response to a
failed MC or FC expressed as an integer from 0 through 65535 (Default = 3).
A periodic-interval keyword in the SRP Configuration mode checkpoint session command allows you to
configure the interval between the sending of macro-checkpoints (FCs) between the active and standby chassis.
The periodic-interval keyword will only appear if a special ICSR optimization feature license has been
Important
purchased and installed. Contact your Cisco account representative for assistance.
configure
context context_name
service-redundancy-protocol variable
checkpoint session periodic-interval minutes
default checkpoint session periodic-interval
ASR 5500 System Administration Guide, StarOS Release 21.5
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Interchassis Session Recovery