designing for scale and differentiation
Nave pictures of the Internet frequently portray a small collection of hosts or LAN's connected by a "cloud" of connectivity. The truth is more complex. The IP-level structure of the Internet is composed from a large number of constituent networks, each of which differs in some or all of transmission technologies, routing protocols, administrative models, security policies, QoS capabilities, pricing mechanisms, and similar attributes. On top of this, a whole new structure of application-layer overlays and content distribution networks, equally diverse in the sorts of ways mentioned above, is rapidly evolving. Virtually any horizontal slice through the current Internet structure reveals a loosely coupled federation of separately defined, operated, and managed entities, interconnected to varying degrees, and often differing drastically in internal requirements and implementation. Intuitively, it is natural to think of each of these entities as existing in a region of the network, with each region having coherent internal technology and policies, and each region managing its interactions with other regions of the net according to some defined set of rules and policies.In this paper, we propose that a key design element in an architecture for extremely large scale, wide distribution and heterogeneous networks is a grouping and partitioning mechanism we call the region . Furthermore we postulate that such a mechanism can provide increased functionality and management of existing unresolved problems in current networks. The paper both describes a proposed definition of the region concept and explores the utility of such a mechanism through a series of examples. We claim that there is significant added benefit to generalizing the idea of the region .
heterogeneity extensibility network architecture scalability