IP drp server:- used for cisco distributed director generally on the 2500 series. The Director uses the DRP (director response protocol) for querying. The above turns the router into an DRP agent
http://www.cisco.com/en/US/docs/app_ntwk_services/waas/distdir/2501/configuration/guide/ovr.html
Ip wccp web-cache: - Enables the WEB-cache service on the device. WCCP is a Cisco-developed content-routing technology that you can use to integrate cache engines into your network infrastructure. The cache engines transparently store frequently accessed content and then fulfill successive requests for the same content, eliminating repetitive transmissions of identical content from web servers
http://www.cisco.com/en/US/docs/switches/lan/catalyst3550/software/release/12.1_13_ea1/configuration/guide/swwccp.html
ip pim dm-fall-back: This command enables PIM dense mode fallback when the RP becomes unavailable
ip send-rp-announce Interface: - Used to configure a router to be a candidate RP for a particular multicast group.
HTH
Narayan
