IPAM
This section describes IP Address Management (IPAM) at the rack level.

During UPF registration, active IPAM instance reserves four address-ranges per UPF per DNN.
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Range-1: Active cluster, nodemgr-1
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Range-2: Active cluster, nodemgr-2
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Range-3: Standby cluster, nodemgr-1
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Range-4: Standby cluster, nodemgr-2
During normal operation, Rack-1 handles UPF-register/release, address-allocate/release for subscribers coming up in GR-instance-1.
If Rack-2 goes down, Rack-1 gets role-change trigger for GR-Instance-2.
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IPAM in Rack-1, restores the content of GR-Instance-2 from local-cache-pod (which was already synced)
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IPAM in Rack-1 handles UPF-Register/Release and address-allocate/release for subscribers coming up with GR-Instance-2 using the restored content in addition to handling GR-Instance-1.
Each IPAM pool is associated to a GR-Instance, with the following:
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Pool name is unique across all the instances.
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Address-ranges are unique within VRF and across all the instances.
The same pool configuration must be configured in both the active and standby cnSGW-CSMF clusters of a particular instance.
During address-allocation, active instance assign free-IP from reserved address-range for the UPF.
Incase new address-ranges is not available, change ownership of standby’s address-range to current active instance and continue assigning address-ranges from it.