Network Working Group
Request for Comments: 1461
D. Throop
Data General Corporation
May 1993

SNMP MIB extension for Multiprotocol Interconnect over X.25

Status of this Memo

This RFC specifies an IAB standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "IAB Official Protocol Standards" for the standardization state and status of this protocol. Distribution of this memo is unlimited.

Abstract

This memo defines a portion of the Management Information Base (MIB) for use with network management protocols in TCP/IP-based internets. In particular, it defines objects for managing Multiprotocol Interconnect (including IP) traffic carried over X.25. The objects defined here, along with the objects in the "SNMP MIB extension for the Packet Layer of X.25"[8], "SNMP MIB extension for LAPB"[7], and the "Definitions of Managed Objects for RS-232-like Hardware Devices" [6], combine to allow management of the traffic over an X.25 protocol stack.

Table of Contents

   1. The Network Management Framework .........................    1
   2. Objects ..................................................    2
   2.1 Format of Definitions ...................................    2
   3. Overview .................................................    3
   3.1 Scope ...................................................    3
   3.2 Structure of MIB objects ................................    3
   4. Definitions ..............................................    4
   5. Acknowledgements .........................................   19
   6. References ...............................................   20
   7. Security Considerations ...................................  21
   8. Author's Address .........................................   21

1. The Network Management Framework

The Internet-standard Network Management Framework consists of three components. These components give the rules for defining objects, the definitions of objects, and the protocol for manipulating objects.

The network management framework structures objects in an abstract information tree. The branches of the tree name objects and the leaves of the tree contain the values manipulated to effect management. This tree is called the Management Information Base or MIB. The concepts of this tree are given in STD 16, RFC 1155, "The Structure of Management Information" or SMI [1]. The SMI defines the trunk of the tree and the types of objects used when defining the leaves. STD 16, RFC 1212, "Towards Concise MIB Definitions" [3], defines a more concise description mechanism that preserves all the principals of the SMI.

The core MIB definitions for the Internet suite of protocols can be found in STD 17, RFC 1213 [4], "Management Information Base for Network Management of TCP/IP-based internets".

STD 15, RFC 1157 [2] defines the SNMP protocol itself. The protocol defines how to manipulate the objects in a remote MIB.

The tree structure of the MIB allows new objects to be defined for the purpose of experimentation and evaluation.

2. Objects

The definition of an object in the MIB requires an object name and type. Object names and types are defined using the subset of Abstract Syntax Notation One (ASN.1) [5] defined in the SMI [1]. Objects are named using ASN.1 object identifiers, administratively assigned names, to specify object types. The object name, together with an optional object instance, uniquely identifies a specific instance of an object. For human convenience, we often use a textual string, termed the descriptor, to refer to objects.

Objects also have a syntax that defines the abstract data structure corresponding to that object type. The ASN.1 language [5] provides the primitives used for this purpose. The SMI [1] purposely restricts the ASN.1 constructs which may be used for simplicity and ease of implementation.

2.1. Format of Definitions

Section 4 contains the specification of all object types contained in this MIB module. The object types are defined using the conventions defined in the SMI, as amended by the extensions specified in "Towards Concise MIB Definitions" [3].

3. Overview

3.1. Scope

Instances of the objects defined below provide management information for Multiprotocol Interconnect traffic on X.25 as defined in RFC 1356 [9]. That RFC describes how X.25 can be used to exchange IP or network level protocols. The multiprotocol packets (IP, CLNP, ES-IS, or SNAP) are encapsulated in X.25 frames for transmission between nodes. All nodes that implement RFC 1356 must implement this MIB.

The objects in this MIB apply to the software in the node that manages X.25 connections and performs the protocol encapsulation. A node in this usage maybe the end node source or destination host for the packet, or it may be a router or bridge responsible for forwarding the packet. Since RFC 1356 requires X.25, nodes that implement RFC 1356 must also implement the X.25 MIB, RFC 1382.

This MIB only applies to Multiprotocol Interconnect over X.25 service. It does not apply to other software that may also use X.25 (for example PAD). Thus the presence, absence, or operation of such software will not directly affect any of these objects. (However connections in use by that software will appear in the X.25 MIB).

3.2. Structure of MIB objects

   The objects of this MIB are organized into three tables:  the
   mioxPleTable, the mioxPeerTable, and the mioxPeerEncTable.  All
   objects in all tables are mandatory for conformance with this MIB.

The mioxPleTable defines information relative to an interface used to carry Multiprotocol Interconnect traffic over X.25. Such interfaces are identified by an ifType object in the Internet-standard MIB [4] of ddn-x25 or rfc877-x25. Interfaces of type ddn-x25 have a self contained algorithm for translating between IP addresses and X.121 addresses. Interfaces of type rfc877-x25 do not have such an algorithm. Note that not all X.25 Interfaces will be used to carry Multiprotocol Interconnect traffic. Those interfaces not carrying such traffic will not have entries in the mioxPleTable. The entries in the mioxPleTable are only for interfaces that do carry Multiprotocol Interconnect traffic over X.25. Entries in the mioxPleTable are indexed by ifIndex to make it easy to find the mioxPleTable entry for an interface.

The mioxPeerTable contains information needed to contact an X.25 Peer to exchange packets. This includes information such as the X.121 address of the peer and a pointer to the X.25 call parameters needed to place the call. The instance identifiers used for the objects in this table are independent of any interface or other tables defined outside this MIB. This table contains the ifIndex value of the X.25 interface to use to call a peer.

The mioxPeerEncTable contains information about the encapsulation type used to communicate with a peer. This table is an extension of the mioxPeerTable in its instance identification. Each entry in the mioxPeerTable may have zero or more entries in this table. This table will not have any entries that do not have correspondent entries in mioxPeerTable.

4. Definitions

          MIOX25-MIB DEFINITIONS  ::= BEGIN

IMPORTS

                  Counter,
                  TimeTicks
                          FROM RFC1155-SMI
                  OBJECT-TYPE
                          FROM RFC-1212
                  DisplayString, transmission,
                  ifIndex
                          FROM RFC1213-MIB
                  InstancePointer
                          FROM RFC1316-MIB
                  X121Address
                          FROM RFC1382-MIB
                  PositiveInteger
                          FROM RFC1381-MIB;

-- IP over X.25 MIB

miox OBJECT IDENTIFIER ::= { transmission 38 }

mioxPle OBJECT IDENTIFIER ::= { miox 1 }

mioxPeer OBJECT IDENTIFIER ::= { miox 2 }

          -- ###########################################################
          --              Ple Table
          -- ###########################################################

-- Systems that implement RFC 1356 must also implement -- all objects in this group.

          mioxPleTable    OBJECT-TYPE
          
                  SYNTAX  SEQUENCE OF MioxPleEntry
                  ACCESS  not-accessible
                  STATUS  mandatory
                  DESCRIPTION
                          "This table contains information relative to
                          an interface to an X.25 Packet Level Entity
                          (PLE)."
                  ::= { mioxPle 1   }
          
          mioxPleEntry    OBJECT-TYPE
                  SYNTAX  MioxPleEntry
                  ACCESS  not-accessible
                  STATUS  mandatory
                  DESCRIPTION
                          "These objects manage the encapsulation of
                          other protocols within X.25."
                  INDEX { ifIndex }
                  ::= { mioxPleTable 1 }

MioxPleEntry ::= SEQUENCE {

                  mioxPleMaxCircuits
                          INTEGER,
                  mioxPleRefusedConnections
                          Counter,
                  mioxPleEnAddrToX121LkupFlrs
                          Counter,
                  mioxPleLastFailedEnAddr
                          OCTET STRING,
                  mioxPleEnAddrToX121LkupFlrTime
                          TimeTicks,
                  mioxPleX121ToEnAddrLkupFlrs
                          Counter,
                  mioxPleLastFailedX121Address
                          X121Address,
                  mioxPleX121ToEnAddrLkupFlrTime
                          TimeTicks,
                  mioxPleQbitFailures
                          Counter,
                  mioxPleQbitFailureRemoteAddress
                          X121Address,
                  mioxPleQbitFailureTime
                          TimeTicks,
                  mioxPleMinimumOpenTimer
                          PositiveInteger,
                  mioxPleInactivityTimer
                          PositiveInteger,
                  mioxPleHoldDownTimer
                          PositiveInteger,
                  mioxPleCollisionRetryTimer
                          PositiveInteger,
                  mioxPleDefaultPeerId
                          InstancePointer
                  }

mioxPleMaxCircuits OBJECT-TYPE

                  SYNTAX  INTEGER (0..2147483647)
                  ACCESS  read-write
                  STATUS  mandatory
                  DESCRIPTION
                          "The maximum number of X.25 circuits that
                          can be open at one time for this interface.
                          A value of zero indicates the interface will
                          not allow any additional circuits (as it may
                          soon be shutdown).  A value of 2147483647
                          allows an unlimited number of circuits."
                  ::= { mioxPleEntry 1 }

mioxPleRefusedConnections OBJECT-TYPE

                  SYNTAX  Counter
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                          "The number of X.25 calls from a remote
                          systems to this system that were cleared by
                          this system.  The interface instance should
                          identify the X.25 interface the call came in
                          on."
                  ::= { mioxPleEntry 2 }

mioxPleEnAddrToX121LkupFlrs OBJECT-TYPE

                  SYNTAX  Counter
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                          "The number of times a translation from an
                          Encapsulated Address to an X.121 address
                          failed to find a corresponding X.121
                          address.  Encapsulated addresses can be
                          looked up in the mioxPeerTable or translated
                          via an algorithm as for the DDN.  Addresses
                          that are successfully recognized do not
                          increment this counter.  Addresses that are
                          not recognized (reflecting an abnormal
                          packet delivery condition) increment this
                          counter.

If an address translation fails, it may be

                          difficult to determine which PLE entry
                          should count the failure.  In such cases the
                          first likely entry in this table should be
                          selected.  Agents should record the failure
                          even if they are unsure which PLE should be
                          associated with the failure."
                  ::= { mioxPleEntry 3 }

mioxPleLastFailedEnAddr OBJECT-TYPE

                  SYNTAX  OCTET STRING (SIZE(2..128))
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                          "The last Encapsulated address that failed
                          to find a corresponding X.121 address and
                          caused mioxPleEnAddrToX121LkupFlrs to be
                          incremented.  The first octet of this object
                          contains the encapsulation type, the
                          remaining octets contain the address of that
                          type that failed.  Thus for an IP address,
                          the length will be five octets, the first
                          octet will contain 204 (hex CC), and the
                          last four octets will contain the IP
                          address.  For a snap encapsulation, the
                          first byte would be 128 (hex 80) and the
                          rest of the octet string would have the snap
                          header."
                  ::= { mioxPleEntry 4 }

mioxPleEnAddrToX121LkupFlrTime OBJECT-TYPE

                  SYNTAX  TimeTicks
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                          "The most recent value of sysUpTime when the
                          translation from an Encapsulated Address to
                          X.121 address failed to find a corresponding
                          X.121 address."
                  ::= { mioxPleEntry 5 }

mioxPleX121ToEnAddrLkupFlrs OBJECT-TYPE

                  SYNTAX  Counter
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                          "The number of times the translation from an
                          X.121 address to an Encapsulated Address
                  
                          failed to find a corresponding Encapsulated
                          Address.  Addresses successfully recognized
                          by an algorithm do not increment this
                          counter.  This counter reflects the number
                          of times call acceptance encountered the
                          abnormal condition of not recognizing the
                          peer."
                  ::= { mioxPleEntry 6 }

mioxPleLastFailedX121Address OBJECT-TYPE

                  SYNTAX  X121Address
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                          "The last X.121 address that caused
                          mioxPleX121ToEnAddrLkupFlrs to increase."
                  ::= { mioxPleEntry 7 }

mioxPleX121ToEnAddrLkupFlrTime OBJECT-TYPE

                  SYNTAX  TimeTicks
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                          "The most recent value of sysUpTime when the
                          translation from an X.121 address to an
                          Encapsulated Address failed to find a
                          corresponding Encapsulated Address."
                  ::= { mioxPleEntry 8 }

mioxPleQbitFailures OBJECT-TYPE

                  SYNTAX  Counter
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                          "The number of times a connection was closed
                          because of a Q-bit failure."
                  ::= { mioxPleEntry 9 }

mioxPleQbitFailureRemoteAddress OBJECT-TYPE

                  SYNTAX  X121Address
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                          "The remote address of the most recent
                          (last) connection that was closed because of
                          a Q-bit failure."
                  ::= { mioxPleEntry 10 }

mioxPleQbitFailureTime OBJECT-TYPE

                  SYNTAX  TimeTicks
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                          "The most recent value of sysUpTime when a
                          connection was closed because of a Q-bit
                          failure.  This will also be the last time
                          that mioxPleQbitFailures was incremented."
                  ::= { mioxPleEntry 11 }

mioxPleMinimumOpenTimer OBJECT-TYPE

                  SYNTAX  PositiveInteger
                  ACCESS  read-write
                  STATUS  mandatory
                  DESCRIPTION
                          "The minimum time in milliseconds this
                          interface will keep a connection open before
                          allowing it to be closed.  A value of zero
                          indicates no timer."
                  DEFVAL { 0 }
                  ::= { mioxPleEntry 12 }

mioxPleInactivityTimer OBJECT-TYPE

                  SYNTAX  PositiveInteger
                  ACCESS  read-write
                  STATUS  mandatory
                  DESCRIPTION
                          "The amount of time time in milliseconds
                          this interface will keep an idle connection
                          open before closing it.  A value of
                          2147483647 indicates no timer."
                  DEFVAL { 10000 }
                  ::= { mioxPleEntry 13 }
          
          mioxPleHoldDownTimer    OBJECT-TYPE
                  SYNTAX  PositiveInteger
                  ACCESS  read-write
                  STATUS  mandatory
                  DESCRIPTION
                          "The hold down timer in milliseconds.  This
                          is the minimum amount of time to wait before
                          trying another call to a host that was
                          previously unsuccessful.  A value of
                          2147483647 indicates the host will not be
                          retried."
                  DEFVAL { 0 }
                  ::= { mioxPleEntry 14 }

mioxPleCollisionRetryTimer OBJECT-TYPE

                  SYNTAX  PositiveInteger
                  ACCESS  read-write
                  STATUS  mandatory
                  DESCRIPTION
                          "The Collision Retry Timer in milliseconds.
                          The time to delay between call attempts when
                          the maximum number of circuits is exceeded
                          in a call attempt."
                  DEFVAL { 0 }
                  ::= { mioxPleEntry 15 }

mioxPleDefaultPeerId OBJECT-TYPE

                  SYNTAX  InstancePointer
                  ACCESS  read-write
                  STATUS  mandatory
                  DESCRIPTION
                          "This identifies the instance of the index
                          in the mioxPeerTable for the default
                          parameters to use with this interface.

The entry identified by this object may have a zero length Encapsulation address and a zero length X.121 address.

These default parameters are used with connections to hosts that do not have entries in the mioxPeerTable. Such connections occur when using ddn-x25 IP-X.25 address mapping or when accepting connections from other hosts not in the mioxPeerTable.

                          The mioxPeerEncTable entry with the same
                          index as the mioxPeerTable entry specifies
                          the call encapsulation types this PLE will
                          accept for peers not in the mioxPeerTable.
                          If the mioxPeerEncTable doesn't contain any
                          entries, this PLE will not accept calls from
                          entries not in the mioxPeerTable."
                  ::= { mioxPleEntry 16 }
          
          -- ###########################################################
          --              Peer Table
          -- ###########################################################

-- Systems that implement RFC 1356 must also implement -- all objects in this group.

mioxPeerTable OBJECT-TYPE

                  SYNTAX  SEQUENCE OF MioxPeerEntry
                  ACCESS  not-accessible
                  STATUS  mandatory
                  DESCRIPTION
                          "This table contains information about the
                          possible peers this machine may exchange
                          packets with."
                  ::= { mioxPeer 1 }

mioxPeerEntry OBJECT-TYPE

                  SYNTAX  MioxPeerEntry
                  ACCESS  not-accessible
                  STATUS  mandatory
                  DESCRIPTION
                          "Per peer information."
                  INDEX { mioxPeerIndex   }
                  ::= { mioxPeerTable 1 }

MioxPeerEntry ::= SEQUENCE {

                  mioxPeerIndex
                          PositiveInteger,
                  mioxPeerStatus
                          INTEGER,
                  mioxPeerMaxCircuits
                          PositiveInteger,
                  mioxPeerIfIndex
                          PositiveInteger,
                  mioxPeerConnectSeconds
                          Counter,
                  mioxPeerX25CallParamId
                          InstancePointer,
                  mioxPeerEnAddr
                          OCTET STRING,
                  mioxPeerX121Address
                          X121Address,
                  mioxPeerX25CircuitId
                          InstancePointer,
                  mioxPeerDescr
                          DisplayString
                  }
          
          mioxPeerIndex   OBJECT-TYPE
                  SYNTAX  PositiveInteger
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                          "An index value that distinguished one entry
                          from another.  This index is independent of
                          any other index."
                  ::= { mioxPeerEntry 1 }

-- Systems can claim conformance with this MIB without -- implementing sets to mioxPeerStatus with a value of -- clearCall or makeCall.
-- All other defined values must be accepted. -- Implementors should realize that allowing these values -- provides richer management, and implementations
-- are encouraged to accept these values. mioxPeerStatus OBJECT-TYPE

                  SYNTAX  INTEGER {
                                  valid (1),
                                  createRequest (2),
                                  underCreation (3),
                                  invalid (4),
                                  clearCall (5),
                                  makeCall (6)
                                  }
                  ACCESS  read-write
                  STATUS  mandatory
                  DESCRIPTION
                          "This reports the status of a peer entry.
                          A value of valid indicates a normal entry
                          that is in use by the agent.  A value of
                          underCreation indicates a newly created
                          entry which isn't yet in use because the
                          creating management station is still setting
                          values.

The value of invalid indicates the entry is no longer in use and the agent is free to delete the entry at any time. A management station is also free to use an entry in the invalid state.

Entries are created by setting a value of createRequest. Only non-existent or invalid entries can be set to createRequest. Upon receiving a valid createRequest, the agent will create an entry in the underCreation state. This object can not be set to a value of underCreation directly, entries can only be created by setting a value of createRequest. Entries that exist in other than the invalid state can not be set to createRequest.

Entries with a value of underCreation are not used by the system and the management station can change the values of other objects in the table entry. Management stations should also remember to configure values in the mioxPeerEncTable with the same peer index value as this peer entry.

An entry in the underCreation state can be set to valid or invalid. Entries in the underCreation state will stay in that state until 1) the agent times them out, 2) they are set to valid, 3) they are set to invalid. If an agent notices an entry has been in the underCreation state for an abnormally long time, it may decide the management station has failed and invalidate the entry. A prudent agent will understand that the management station may need to wait for human input and will allow for that possibility in its determination of this abnormally long period.

Once a management station has completed all fields of an entry, it will set a value of valid. This causes the entry to be activated.

Entries in the valid state may also be set to makeCall or clearCall to make or clear X.25 calls to the peer. After such a set request the entry will still be in the valid state. Setting a value of makeCall causes the agent to initiate an X.25 call request to the peer specified by the entry. Setting a value of clearCall causes the agent to initiate clearing one X.25 call present to the peer. Each set request will initiate another call or clear request (up to the maximum allowed); this means that management stations that fail to get a response to a set request should query to see if a call was in fact placed or cleared before retrying the request. Entries not in the valid state can not be set to makeCall or clearCall.

The values of makeCall and clearCall provide for circuit control on devices which perform Ethernet Bridging using static circuit assignment without address recognition; other devices which dynamically place calls based on destination addresses may reject such requests.

                          An agent that (re)creates a new entry
                          because of a set with createRequest, should
                          also (re)create a mioxPeerEncTable entry
                          with a mioxPeerEncIndex of 1, and a
                          mioxPeerEncType of 204 (hex CC)."
                  ::= { mioxPeerEntry 2 }

mioxPeerMaxCircuits OBJECT-TYPE

                  SYNTAX  PositiveInteger
                  ACCESS  read-write
                  STATUS    mandatory
                  DESCRIPTION
                          "The maximum number of X.25 circuits allowed
                          to this peer."
                  DEFVAL { 1 }
                  ::= { mioxPeerEntry 3 }

mioxPeerIfIndex OBJECT-TYPE

                  SYNTAX  PositiveInteger
                  ACCESS  read-write
                  STATUS  mandatory
                  DESCRIPTION
                          "The value of the ifIndex object for the
                          interface to X.25 to use to call the peer."
                  DEFVAL { 1 }
                  ::= { mioxPeerEntry 4 }

mioxPeerConnectSeconds OBJECT-TYPE

                  SYNTAX  Counter
                  ACCESS  read-only
                  STATUS  mandatory
                  DESCRIPTION
                          "The number of seconds a call to this peer
                          was active.  This counter will be
                          incremented by one for every second a
                          connection to a peer was open.  If two calls
                  
                          are open at the same time, one second of
                          elapsed real time will results in two
                          seconds of connect time."
                  ::= { mioxPeerEntry 5 }

mioxPeerX25CallParamId OBJECT-TYPE

                  SYNTAX  InstancePointer
                  ACCESS  read-write
                  STATUS  mandatory
                  DESCRIPTION
                          "The instance of the index object in the
                          x25CallParmTable from RFC 1382 for the X.25
                          call parameters used to communicate with the
                          remote host.  The well known value {0 0}
                          indicates no call parameters specified."
                  DEFVAL { {0 0} }
                  ::= { mioxPeerEntry 6 }
          
          mioxPeerEnAddr  OBJECT-TYPE
                  SYNTAX    OCTET STRING (SIZE (0..128))
                  ACCESS  read-write
                  STATUS  mandatory
                  DESCRIPTION
                          "The Encapsulation address of the remote
                          host mapped by this table entry.  A length
                          of zero indicates the remote IP address is
                          unknown or unspecified for use as a PLE
                          default.
          
                          The first octet of this object contains the
                          encapsulation type, the remaining octets
                          contain an address of that type.  Thus for
                          an IP address, the length will be five
                          octets, the first octet will contain 204
                          (hex CC), and the last four octets will
                          contain the IP address.  For a snap
                          encapsulation, the first byte would be 128
                          (hex 80) and the rest of the octet string
                          would have the snap header."
                  DEFVAL { ''h }
                  ::= { mioxPeerEntry 7 }

mioxPeerX121Address OBJECT-TYPE

                  SYNTAX  X121Address
                  ACCESS  read-write
                  STATUS  mandatory
                  DESCRIPTION
                          "The X.25 address of the remote host mapped
                  
                          by this table entry.  A zero length string
                          indicates the X.25 address is unspecified
                          for use as the PLE default."
                  DEFVAL { ''h }
                  ::= { mioxPeerEntry 8 }

-- Systems can claim conformance to this MIB without -- implementing sets to mioxPeerX25CircuitId.
-- However systems that use PVCs with RFC1356
-- are encouraged to implement sets. mioxPeerX25CircuitId OBJECT-TYPE

                  SYNTAX  InstancePointer
                  ACCESS  read-write
                  STATUS  mandatory
                  DESCRIPTION
                          "This object identifies the instance of the
                          index for the X.25 circuit open to the peer
                          mapped by this table entry.  The well known
                          value {0 0} indicates no connection
                          currently active.  For multiple connections,
                          this identifies the index of a multiplexing
                          table entry for the connections.  This can
                          only be written to configure use of PVCs
                          which means the identified circuit table
                          entry for a write must be a PVC."
                  DEFVAL { {0 0} }
                  ::= { mioxPeerEntry 9 }
          
          mioxPeerDescr   OBJECT-TYPE
                  SYNTAX  DisplayString (SIZE (0..255))
                  ACCESS  read-write
                  STATUS  mandatory
                  DESCRIPTION
                          "This object returns any identification
                          information about the peer.  An agent may
                          supply the comment information found in the
                          configuration file entry for this peer.  A
                          zero length string indicates no information
                          available."
                  DEFVAL { ''h }
                  ::= { mioxPeerEntry 10 }
          
          -- ###########################################################
          --              Peer Encapsulation Table
          -- ###########################################################

mioxPeerEncTable OBJECT-TYPE

                  SYNTAX  SEQUENCE OF MioxPeerEncEntry
                  ACCESS  not-accessible
                  STATUS  mandatory
                  DESCRIPTION
                          "This table contains the list of
                          encapsulations used to communicate with a
                          peer.  This table has two indexes, the first
                          identifies the peer, the second
                          distinguishes encapsulation types.

The first index identifies the corresponding entry in the mioxPeerTable. The second index gives the priority of the different encapsulations.

The encapsulation types are ordered in priority order. For calling a peer, the first entry (mioxPeerEncIndex of 1) is tried first. If the call doesn't succeed because the remote host clears the call due to incompatible call user data, the next entry in the list is tried. Each entry is tried until the list is exhausted.

For answering a call, the encapsulation type requested by the peer must be found the list or the call will be refused. If there are no entries in this table for a peer, all call requests from the peer will be refused.

                          Objects in this table can only be set when
                          the mioxPeerStatus object with the same
                          index has a value of underCreation.  When
                          that status object is set to invalid and
                          deleted, the entry in this table with that
                          peer index must also be deleted."
                  ::= { mioxPeer 2 }

mioxPeerEncEntry OBJECT-TYPE

                  SYNTAX  MioxPeerEncEntry
                  ACCESS  not-accessible
                  STATUS  mandatory
                  DESCRIPTION
                          "Per connection information."
                  INDEX { mioxPeerIndex, mioxPeerEncIndex}
                  ::= { mioxPeerEncTable 1 }

MioxPeerEncEntry ::= SEQUENCE {

                  mioxPeerEncIndex
                          PositiveInteger,
                  mioxPeerEncType
                          INTEGER
                  }
          
          mioxPeerEncIndex        OBJECT-TYPE
                  SYNTAX  PositiveInteger
                  ACCESS  read-only
                  STATUS    mandatory
                  DESCRIPTION
                          "The second index in the table which
                          distinguishes different encapsulation
                          types."
                  ::= { mioxPeerEncEntry 1 }

mioxPeerEncType OBJECT-TYPE

                  SYNTAX  INTEGER (0..256)
                  ACCESS  read-write
                  STATUS  mandatory
                  DESCRIPTION
                          "The value of the encapsulation type.  For
                          IP encapsulation this will have a value of
                          204 (hex CC).  For SNAP encapsulated
                          packets, this will have a value of 128 (hex
                          80).  For CLNP, ISO 8473, this will have a
                          value of 129 (hex 81).  For ES-ES, ISO 9542,
                          this will have a value of 130 (hex 82).  A
                          value of 197 (hex C5) identifies the Blacker
                          X.25 encapsulation.  A value of 0,
                          identifies the Null encapsulation.
                  
                          This value can only be written when the
                          mioxPeerStatus object with the same
                          mioxPeerIndex has a value of underCreation.
                          Setting this object to a value of 256
                          deletes the entry.  When deleting an entry,
                          all other entries in the mioxPeerEncTable
                          with the same mioxPeerIndex and with an
                          mioxPeerEncIndex higher then the deleted
                          entry, will all have their mioxPeerEncIndex
                          values decremented by one."
                  ::= { mioxPeerEncEntry 2 }
          
          -- ###########################################################
          
          END

5. Acknowledgements

This document was produced by the x25mib working group:

Fred Baker, ACC
Art Berggreen, ACC
Frank Bieser
Gary Bjerke, Tandem
Bill Bowman, HP
Christopher Bucci, Datability
Charles Carvalho, ACC
Jeff Case, University of Tennessee at Knoxville Angela Chen, HP
Carson Cheung, BNR
Tom Daniel, Spider Systems
Chuck Davin, MIT
Billy Durham, Honeywell
Richard Fox, Synoptics
Doug Geller, Data General
Herve Goguely, LIR Corp
Andy Goldthorpe, British-Telecom
Walter D. Guilarte
David Gurevich
Steve Huston, Consultant
Jon Infante, ICL
Frank Kastenholz, FTP Software
Zbigniew Kielczewski, Eicon
Cheryl Krupezak, Georgia Tech
Mats Lindstrom, Diab Data AB
Andrew Malis, BBN
Evan McGinnis, 3Com
Gary (G.P.)Mussar, BNR
Chandy Nilakantan, 3Com
Randy Pafford, Data General
Ragnar Paulson, The Software Group Limited Dave Perkins, Synoptics
Walter Pinkarschewsky, DEC
Karen Quidley, Data General
Chris Ranch, Novell
Paul S. Rarey, DHL Systems Inc.
Jim Roche, Newbridge Research
Philippe Roger, LIR Corp.
Timon Sloane
Mike Shand, DEC
Brad Steina, Microcom
Bob Stewart, Xyplex
Tom Sullivan, Data General
Rodney Thayer, Sable Technology Corporation

Mark Therieau, Microcom
Jane Thorn, Data General
Dean Throop, Data General
Maurice Turcotte, Racal Datacom
Mike Zendels, Data General

6. References

   [1] Rose M., and K. McCloghrie, "Structure and Identification of
   
       Management Information for TCP/IP-based internets", STD 16, RFC
       1155, Performance Systems International, Hughes LAN Systems, May
       1990.
   
   [2] Case, J., Fedor, M., Schoffstall, M., and J. Davin, "Simple
       Network Management Protocol", STD 15, RFC 1157, SNMP Research,
       Performance Systems International, Performance Systems
       International, MIT Laboratory for Computer Science, May 1990.
   
   [3] Rose, M. and K. McCloghrie, Editors, "Towards Concise MIB
       Definitions", STD 16, RFC 1212, Performance Systems
       International, Hughes LAN Systems, March 1991.
   
   [4] Rose M., Editor, "Management Information Base for Network
       Management of TCP/IP-based internets", STD 17, RFC 1213.
       Performance Systems International, March 1991.

[5] "Information processing systems - Open Systems Interconnection -

Specification of Abstract Syntax Notation One (ASN.1)", International Organization for Standardization. International Standard 8824, December, 1987.

   [6] Stewart, B., Editor, "Definitions of Managed Objects for RS-232-
       like Hardware Devices", RFC 1317, Xyplex, Inc., April 1992.
   
   [7] Throop, D., and F. Baker, "SNMP MIB extension for X.25 LAPB", RFC
       1381, Data General Corporation, Advanced Computer Communications,
       November 1992.
   
   [8] Throop, D., Editor, "SNMP MIB extension for the X.25 Packet
       Layer", RFC 1382, Data General Corporation, November 1991.
   
   [9] Malis, A., Robinson, D., and R. Ullmann "Multiprotocol
       Interconnect on X.25 and ISDN in the Packet Mode", RFC 1356, BBN
       Communications, Computervision Systems Integration, Process
       Software Corporation, August 1992.

7. Security Considerations

Security issues are not discussed in this memo.

8. Author's Address

Dean D. Throop
Data General Corporation
62 Alexander Dr.
Research Triangle Park, NC 27709

   Phone: (919) 248-6081
   EMail: throop@dg-rtp.dg.com