BGP Blackhole Users Guide
The PennREN network implements several BGP communities to allow for traffic engineering by members without requiring the intervention from the PennREN NOC or engineering staff.
During incidents of network distress, e.g. traffic floods saturating upstream links due to denial of service attacks, a member may desire to signal the upstream routers within PennREN to discard this traffic before it reaches a downstream member.
The community 14877:666 can be added to routes which will signal PennREN routers to discard traffic upon ingress into any of PennREN’s routers. The only limitation to the use of this community is that the prefix in which the blackhole community is applied to must already be permitted by current ingress prefix filters applied to their BGP session. Any prefix length is supported currently.Up to /32 for IPv4 and /128 for IPv6.