Growth of the Internet strains the Internet rout- ing system to its limits. Forming strata, and using them for aggregation of routing informa- tion may provide useful enhancements to the cur- rent routing and addressing architecture (CIDR). Strata may also be used to introduce an additional level of routing hierarchy. However, doing this in- troduces a broad set of open issues. In the near term it would be prudent to focus just on using strata for aggregation, and defer stratum-based address allocation till such need could be justified, and the open issues resolved.