RFC 1291 (rfc1291) - Page 3 of 10

Mid-Level Networks Potential Technical Services

RFC 1291             Potential Technical Services          December 1991


     o  Technical services

     o  Experimental sites for testing and dissemination of new
        software and technology to end sites on the network

   In addition, the following services are mentioned briefly which are
   discussed in detail elsewhere [SSM91, ML91]:

     o  Network Operation services and the interaction between
        different mid-level networks in this area

     o  Network Information services

3. Technical Services

   The Internet has grown to be an essential entity because of the
   services that it offers to its end users. The list of services is
   long and growing, but some services are more widely used and deployed
   than others. This section attempts to list and discuss those
   technical services that could help a mid-level network provide robust
   and improved services to its end sites.

3.1 Domain Name Service

   According to the NSFnet traffic statistics collected for May 1991,
   about 7% of the packets on the NSFnet backbone were domain nameserver
   (DNS) packets. This is a significant amount of traffic, and since
   most of the other network applications depend on this service, a
   robust DNS service is critical to any Internet site.

   Proper location of secondary nameservers so that they are located on
   different physical networks can increase the reliability of this
   service to a large extent [MOC87a, MOC87b]. However, the nature of
   the service requires that the nameservers for the next highest level
   be available in order to resolve names outline-mode side of one's
   domain.  Thus, for "foo.princeton.edu" to resolve "a.mid.net", the
   root nameservers which point to mid.net's nameservers have to be
   reachable.

   To make the service more reliable, the mid-level network could have
   at least one nameserver that is able to resolve nameserver queries
   for all domains directly connected to it. Thus, in the event that the
   entire mid-level network becomes isolated from the rest of the
   Internet, applications can still resolve queries for sites directly
   connected to the mid-level network. Without this functionality, there
   is no way of resolving a name if the root (or higher level)
   nameservers become unreachable, even if the query is for a site that
   is directly connected and reachable.



Aggarwal