Client types in Velocity: Simple

Routing Client
The routing client offers better performance than the simple client because it contains a routing table that is kept up to date by the lead hosts. The routing table is used to track cached object placement across all cache hosts in the cluster and identifies all cache hosts in the cluster. The routing client uses this table to optimize performance by making requests to the cache host where the object is physically located. For information about how to configure a routing client, see How to: Get Started with a Routing Client (XML) (Velocity) and How to: Get Started with a Routing Client (Code) (Velocity).

Note 
In order to use a routing client, the computer that is running the cache-enabled client application must have network connectivity to all cache servers in the cluster.

Simple Client
Whenever possible, the routing client should always be used. Due to networking topologies, there may be cases where client applications can only access some of the cache servers in the cache cluster. In those cases, the simple client can be used to provide distributed cache resources.

To work in scenarios of limited cache server connectivity, the simple client has been designed to only require access to one cache host in the cluster. It has no routing capabilities and does not track where each cached object is stored. Because the simple client has no routing capabilities, requested cached objects often have to traverse additional cache hosts before reaching the simple client. This indirect path makes the simple client less efficient than the routing client.

For more information about how to configure a simple client, see How to: Get Started with a Simple Client (XML) (Velocity) and How to: Get Started with a Simple Client (Code) (Velocity).