What are two different topologies?

We can install the OCS FE using any one of the following two topologies!

Consolidated Topologies: If you select consolidated topology, the front-end server, the Web Components Server, the Web Conferencing Server, and the A/V Conferencing Server are installed together on each Enterprise Edition Server within a pool.

It reduces the number of hardware servers required while maintaining high availability.

It simplifies the deployment and administration.

Reduced throughput per server.

Recommended for the organization that plan to support only instant messaging and presence.

Expanded Topologies: If you select expanded topology, the front-end server, the Web Components Server, the Web Conferencing Server, and the A/V Conferencing Server is installed on a dedicated computer. A Web Components Server can be collocated with each front-end server.

It increases the number of hardware servers required while maintaining high availability.

Recommended for the organizations for which high availability and maximum performance throughput are important.

provides benefits with regard to scalability and high availability, but creates additional complexity in the administration and deployment of the pool.