RFC 1658 (rfc1658) - Page 2 of 18


Definitions of Managed Objects for Character Stream Devices using SMIv2



Alternative Format: Original Text Document



RFC 1658                     Character MIB                     July 1994


      o    RFC 1445 [3] which defines the administrative and other
           architectural aspects of the framework.

      o    RFC 1448 [4] which defines the protocol used for network
           access to managed objects.

   The Framework permits new objects to be defined for the purpose of
   experimentation and evaluation.

2.1.  Object Definitions

   Managed objects are accessed via a virtual information store, termed
   the Management Information Base or MIB.  Objects in the MIB are
   defined using the subset of Abstract Syntax Notation One (ASN.1)
   defined in the SMI.  In particular, each object object type is named
   by an OBJECT IDENTIFIER, an administratively assigned name.  The
   object type together with an object instance serves to uniquely
   identify a specific instantiation of the object.  For human
   convenience, we often use a textual string, termed the descriptor, to
   refer to the object type.

3.  Overview

   The Character MIB applies to ports that carry a character stream,
   whether physical or virtual, serial or parallel, synchronous or
   asynchronous.  The most common example of a character stream device
   is a hardware terminal port with an RS-232 interface.  Another common
   hardware example is a parallel printer port, say with a Centronics
   interface.  The concept also includes virtual terminal ports, such as
   a software connection point for a remote console.

   The Character MIB is mandatory for all systems that offer character
   stream ports.  This includes, for example, terminal servers,
   general-purpose time-sharing hosts, and even such systems as a bridge
   with a (virtual) console port.  It may or may not include character
   ports that do not support network sessions, depending on the system's
   needs.

   The Character MIB's central abstraction is a port.  Physical ports
   have a one-to-one correspondence with hardware ports. Virtual ports
   are software entities analogous to physical ports, but with no
   hardware connector.

   Each port supports one or more sessions.  A session represents a
   virtual connection that carries characters between the port and some
   partner.  Sessions typically operate over a stack of network
   protocols.  A typical session, for example, uses Telnet over TCP.




Stewart