Due to a ransomware attack, the wiki was reverted to a July 2022 version. . We apologize for the lack of a more recent valid backup.
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- Group Identifier will be represented as a simple Integer. Will be revisited at a later point of time to see if it needs to be aligned with PortNumber representation
- Group objects for a device will only be created/updated/removed by current Master controller instance.
- So as, the Group Identifier allocation/management also will only be done by current Master controller instance.
- Replication:
- Alternative1: Groups for a device are only replicated in the Master controller instance and another potential candidate instance.
- Alternative2: Since typically the number Groups per device will not be huge, Groups are replicated in all the instances of the clusercluster
- Resolution: Though the Groups are created only by Master controller instance, they may typically be required/used by all controller instances in the cluster. So it is recommended to replicate the Group database in all the instances of the cluster.
- Consistency & Durability:
- Eventual consistency or Strong consistency for Group Objects?
- Do we need durability?
- Resolution: Eventual consistency seems to be sufficient for Group store. Durability is not needed.
- Group creation/update/removal/query request can be submitted in any controller instance and that instance will take care of routing the request to current Master controller instance.
- Group creation API does not return any Group object as in some scenarios the request needs to be routed to Master controller instance where the Group object gets created. Application should use Group Query API to retrieve the Group object after creation.
- Group query API blocks the caller thread until it retrieves from the remote Master controller instance if the instance where request is submitted is not having the control over that device
- Group query API returns the Group object even if the Group object is in PENDING_ADD state
- Group subsystem generates GROUP_ADDED event only after it receives confirmation from Data plane through Barrier Reply or Group Description Reply (In the first phase, it will be based on Group Description Reply)
- Authoritativeness:
- Group store has full authority of groups in the device.
- Group store will wipe off any extraneous groups in a device if found during AUDIT. That means creation of groups bypassing the Group store or any default groups existing in a device can not be supported
- Group Key
- As part of the Group operations, Group subsystem accepts a cookie from the applications in the form of a GroupKey. This is to facilitate applications to query the Group sub system based on cookie instead of Group Identifier.
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