enforce server , detection/prevention servers, agent , oracle DB etc.
it can 3 tier , 2 tier or single tier architecture.
Have you bought DLP ? if yes, contact Symantec sales or partner for the install help.
also checj this link
https://www-secure.symantec.com/connect/forums/symantec-dlp-implementation-planning-and-design-enterprise#/comment-8429811