RFC 985 (rfc985) - Page 4 of 23

Requirements for Internet gateways - draft

RFC 985                                                         May 1986
Requirements for Internet Gateways -- DRAFT


   1.2.  The Internet Gateway Model

      An Internet gateway is a self-contained, stand-alone packet switch
      that performs the following functions:

         1.  Interfaces to two or more packet-switching networks,
             including encapsulation, address transformation and flow
             control.

         2.  Conforms to specific DARPA Internet protocols specified in
             this document, including the Internet Protocol (IP),
             Internet Control Message Protocol (ICMP), Exterior Gateway
             Protocol (EGP) and others as necessary.

         3.  Supports an interior gateway protocol (IGP) reachability or
             routing algorithm in cases of multiple gateways operating
             as a system.  Supports the EGP reachability algorithm to
             exchange routes between systems, in particular the DARPA
             "core" system operated by BBN.

         4.  Receives and forwards Internet datagrams consistent with
             good engineering practice in the management of resources,
             congestion control and fairness.  Recognizes various error
             conditions and generates ICMP error and information
             messages as required.

         5.  Provides system support facilities, including loading,
             debugging, status reporting, exception reporting and
             control.

      In some configurations gateways may be connected to
      packet-switching local nets that provide generic local-net
      routing, error-control and resource-management functions.  In
      others gateways may be directly connected via serial lines, so
      that these functions must be provided by the gateways themselves.

      There are three typical scenarios that should be addressed by
      gateway vendors:

         1.  National or regional network.  Gateways of this class
             should be capable of switching multiple continuous flows in
             the 1.5-Mbps range at rates to several thousand packets per
             second.  They will be high-performance, possibly redundant,
             multiple-processor devices, probably procured as a system
             and operated remotely from a regional or national
             monitoring center.  The design of these gateways should
             emphasize high aggregate throughput, throughput-sensitive


NTAG