The architectural change resulted in five server roles, three of which were core to the product:
- Edge Transport for routing and anti-malware from the edge of the organization
- Hub Transport for internal routing and policy enforcement
- Mailbox for storage of data
- Client Access for client connectivity and web services
- Unified Messaging for voice mail and voice access
Read more at source: http://blogs.technet.com/b/exchange/archive/2013/01/23/exchange-2013-server-role-architecture.aspx
Cheers,
Anderson Patricio
http://www.msexchange.org/blogs/patricio/
http://www.andersonpatricio.ca
Twitter: @apatricio