для Cisco Cisco IOS Software Release 12.2(14)S

BGP peering sessions must be established, and BGP ORF capabilities must be enabled on each 
participating router before prefix-based ORF announcements can be sent or received.

The BGP Prefix-Based Outbound Route Filtering feature does not support IP multicast routes.

IP addresses that are used for outbound route filtering must be defined in an IP prefix-list. BGP 
distribute lists and IP access lists are not supported. 

Outbound route filtering is configured on only a per-address family basis and cannot be configured 
under the general session or BGP routing process (

Router(config-router)#

). 

Outbound route filtering is configured for only external peering sessions. 

To configure BGP prefix-based outbound route filtering, you must understand the following concepts:

The BGP Prefix-Based Outbound Route Filtering feature uses Border Gateway Protocol (BGP) 
outbound route filter (ORF) send and receive capabilities to minimize the number of BGP updates that 
are sent between BGP peers. Configuring this feature can help reduce the amount of system resources 
required for generating and processing routing updates by filtering out unwanted routing updates at the 
source. For example, this feature can be used to reduce the amount of processing required on a router 
that is not accepting full routes from a service provider network.