When set to 1, the CDR_ROUTER environment variable disables intermediate acknowledgements of transactions in hierarchical topologies. The normal behavior for intermediate servers is to send acknowledgements if they receive an acknowledgment from the next server in the replication tree (can be a leaf server) or if the transaction is stored in the local queue. Use the CDR_ENV configuration parameter to set this environment variable. For more information, see CDR_ENV Configuration Parameter.
If CDR_ROUTER is set at the hub server, an acknowledgement will be sent only if the hub server receives acknowledgement from all of its leaf servers. Transactions will not be acknowledged even if they are stored in the local queue of the hub server.
If CDR_ROUTER is not set at hub server, the hub server will send an acknowledgement if the transaction is stored in the local queue at the hub server or if the hub server received acknowledgement from all of its leaf servers.