Cisco IOS different names with different Features

Different types of Cisco IOSs with different features are available for download with different names.
Cisco IOSs can be selected and downloaded as per the features they provide. Here is the brief definition of Eight Different types of IOSs having specific features. Choose what you need for you company by understanding with IOS name.
• IP Base
IP Base without Crypto-Entry level Cisco IOS Software image (Classic IP Data + trunking and DSL)
• IP Voice
IP Voice without Crypto, Adds VoIP, VoFR to IP Base (Adds Voice to Data)
• SP Services
Adds SSH/SSL, ATM, VoATM, MPLS, etc. to IP Voice (Adds SP Services to Voice & Data)
• Advanced Security
Adds Cisco IOS FW, IDS/IDP, NAC, SSH/SSL, IPsec VPN, etc. to IP Base (Add Security/VPN to Data)
• Enterprise Base
Enterprise Base without Crypto, Adds Enterprise Layer 3 routed protocols (AT, IPX, etc.) and IBM support to IP Base (Add Multiprotocol Services to Data)
• Enterprise Services
Enterprise Services without Crypto4-Adds full IBM support, Service Provider Services to Enterprise Base (Merge Enterprise Base & SP Services)
• Advanced IP Services-Adds IPv6
Advanced Security to SP Services (Merge Advanced Security & SP Services)
• Advanced Enterprise Services-Full Cisco IOS Software
Merge Advanced IP Services & Enterprise Services