SAP Fiori Portal Single Sign on with windows Active Directory

Hi Dear,

we are going to configure SSO on SAP Fiori with windows Actvie Directory Server here is my setup

• SAP NW Gateway : Suse Linux
• SAP ECC : Suse Linux
• Active Directory : windows 2012 server

My question is

1. am i need to purchase any additional plugin for GW and ECC server to enable sso or it is available i default system
2. Is there any step by tep guide or document available please share link
3. i have another issue as our active directory user name is greater then 12 character , can it cause our SSO configuration or SSO allow more then 12 character to login fiori portal    

Please share your experience