But please stop talking about _a lot of interface changes_ etc withouth referencing to the type of network. In case of leased-links network I can built the network of ANY size; and limitations depends of the link stability, not of the network size.
I was talking about ISP network which mostly is leased-line based. It depends on link stability and router stability. As I pointed out in my previous message, the more router and link a network has (i.e. the large scaled network), the large chance of having link flapping and router crashes (if you think in percentage sense), the more flooding, SPF calculation and LSDB update all routers in the network have to handle. If there is a hierarchy, then only a portion of routers (not all the routers) would need to handle flooding, SPF calculation and LSDB update. Also, the large the size of network (lots of routers and links), the bigger the LSDB and the higher complexity of SPF calculation. --Jessica