Setting up a gateway topology

You can know about the detailed working of gateway replication and the procedure to set up the same.

Gateway replication uses gateway servers to collect and distribute replication information effectively across a replicating network. The primary benefit of gateway replication is the reduction of network traffic.

Gateway servers must be masters (writable). The following figure illustrates how gateway replication works:

The graphic shows four gateway servers that interconnect with each other. Each gateway server in turn interconnects with the peer and replica servers within its own replication site. — Figure 1. A replicating network with Gateway servers

The replicating network in the preceding figure contains four replication sites, each containing a gateway server. A gateway server:

Collects replication updates from the peer/master servers in the replication site where it resides and sends the updates to all the other gateway servers within the replicating network.
Collects replication updates from other gateway servers in the replication network and sends those updates to the peers/masters and replicas in the replication site where it resides.

Gateway servers use server IDs and consumer IDs to determine which updates are sent to other gateway servers in the replicating network and which updates are sent to local servers within the replication site.

To set up gateway replication, you must create at least two gateway servers. The creation of a gateway server establishes a replication site. You must then create replication agreements between the gateway and any masters/peers and replicas you want to include in that gateway's replication site.

Gateway servers must be masters (writable). If you attempt to add the gateway object class, ibm-replicaGateway, to a subentry that is not a master, an error message is returned.

There are two methods for creating a gateway server. You can:

Create a new gateway server
Convert an existing master server to a gateway server

Note: It is very important that you assign only one gateway server per replication site. The master and replica servers within the replication site can only have agreements with the gateway server for that site.