RFC 1291 (rfc1291) - Page 2 of 10

Mid-Level Networks Potential Technical Services

RFC 1291             Potential Technical Services          December 1991


1. Introduction

   Over the past few years, the Internet has grown to be a very large
   entity and its dependability is critical to its users. Furthermore,
   due to the size and nature of the network, the trend has been to
   decentralize as many network functions (such as domain name-service,
   whois, etc.) as possible. Efforts are being made in resource
   discovery [SHHH90] so that the work of researchers is not lost in the
   volumes of data that is available on the Internet.

   A side result of this growth has been the logical structure imposed
   in the Internet of networks classified by function. Tangible examples
   in the present state are the NSFnet national backbone, the mid-
   level/regional networks and campus networks. Each of these can be
   viewed as hierarchies within an organization, each serving a slightly
   different function than the other (campus LANs providing access to
   local resources, mid-level networks providing access to remote
   resources, etc.). The functions of each hierarchy then become the
   "services" offered to the organizational layer below it, who in turn
   depend on these services.

   This document proposes a set of basic technical services that could
   be offered by a mid-level network. These services would not only
   increase the robustness of the mid-level network itself, but would
   also serve to structure the distribution of resources and services
   within the Internet. It also proposes a uniform naming convention for
   locating the hosts offering these services.

2. The Generic Model

   The Internet model that is used as the basis for this document is a
   graph of mid-level networks connected to one another, each in turn
   connecting the campus/organization networks and with the end users
   attached to the campus networks. The model assumes that the mid-level
   networks constitute the highest level of functional division within
   the Internet hierarchy described above (this could change in the
   unforeseen future). With this model in perspective, this document
   addresses the objectives of minimizing unnecessary traffic within the
   Internet as well as making the entire structure as robust as
   possible.

   The proposed structure is a derived extension of organizational LANs
   where certain services are offered within the organizational LAN
   itself, such as nameservice, mail, shared files, single or
   hierarchical points of contact for problems, etc.

   The following are the services that are discussed as possible
   functions of a mid-level network:



Aggarwal