Yes, you need cluster license to use clustering in WAAS mobile servers.
The Cisco WAAS Mobile Cluster License (WAAS-MBL-CLST-LIC) provides with a cost-effective licensing solution for high availability (e.g., 1:1 or 1:N redundancy) and multi-data center deployments where applications and Cisco WAAS Mobile servers are hosted in multiple data centers.
Using Cluster Licenses, you only require one license per client, irrespective of the server configuration (redundant/non-redundant). Note that for each redundant Cisco WAAS Mobile Server in a cluster, one Cluster License must be procured. This license is in lieu of purchasing a Cisco WAAS Mobile Server license for that server.
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