Cisco Official Support

IP Routing
http://www.cisco.com/en/US/tech/tk365/tsd_technology_support_protocol_home.html

ALL  Types of Tunneling http://www.cisco.com/en/US/tech/tk827/tk369/tech_configuration_examples_list.html

ACL
http://www.cisco.com/en/US/tech/tk648/tk361/tk821/tsd_technology_support_sub-protocol_home.html

DHCP
http://www.cisco.com/en/US/tech/tk648/tk361/tk848/tsd_technology_support_sub-protocol_home.html

NAT
http://www.cisco.com/en/US/tech/tk648/tk361/tk438/tsd_technology_support_sub-protocol_home.html