Border Gateway Protocol (BGP) routing information packet includes an autonomous system (AS) path domain. The AS-Path filter specifies the matching condition for the AS path domain.
The BGP routing information includes a community attribute domain. It is used to identify a community. The community filter specifies the matching condition for the community attribute domain.
The Extcommunity-filter is used only in BGP. The extended community of BGP supports only the Route-Target (RT) extended community of Virtual Private Network (VPN). The Extcommunity-filter specifies matching rules for the extended community attribute.
Through Route Distinguisher (RD), the VPN instance implements the independency of address space and identifies the IPv4 and IPv6 prefixes of the same address space. The RD attribute filter specifies matching conditions for different RDs.