Hi, this may be a OOO..LD topic which is talked, discussed or agrued for year. ISP networks may need to be optimized continuously. But, it seems people have different view of optimization when they use this word at different place; sometimes optimization means adding more access router, add more link bandwidth or add more servers; while it could be used to point the requirement on removing subareas in OSPF or simplify network structure. Is there a common sense on the target of network optimization? or is there common startup line of such work? What should be the model of a optimized ISP network ( or PoP site) ? Is there books on this topic? Joe __________________________________ Meet your soulmate! Yahoo! Asia presents Meetic - where millions of singles gather http://asia.yahoo.com/meetic