"The Cisco Catalyst 3750 Series is available with either the IP Base image or the IP Services image. The IP Base image feature set includes advanced quality of service (QoS), rate-limiting, access control lists (ACLs), and basic static and Routing Information Protocol (RIP) routing capability. The IP Services image provides a richer set of enterprise-class features, including advanced hardware-based IP unicast and multicast routing.
An additional Advanced IP Services license is also available. This license is required for IPv6 routing (Layer 3 switching)."
From this page: »www.cisco.com/en/US/prod/collate···991.html
If you go down the list of features it states which ones require the IP Services image.