I've been trying to find out any logical reason why Ciscos limit me to 16 communities per route. I'm not asking on cisco-nsp as I want to know whether other routers suffer this limitation. Having read and reread rfc1771 and rfc1997, I think the community attribute list is limited by (a) the message length (not really relevant) and (b) the attribute length. The latter appears to be mainly an issue of whether one can be bothered to use extended-length in lieu of non-extended length. Even without using extended-length you have 255 bytes to play with which my calculation gives you 61 or 62 community attributes to play with. So: a) Have I just read the RFC wrong? b) Does other s/w (GateD. Bay etc.) have the same limitation? c) What happens if I try and feed routes with lots of community attributes to a Cisco, (perhaps I feed routes with less than 16 communities on but have set community additive)? Does it drop some randomly? Given that some people use 666 style filtering to prevent advertisement of routes to peers, could this cause leaks? (yes, I have an application for more than 16 communities per route). -- Alex Bligh GX Networks (formerly Xara Networks)