Network Working Group D. Throop
Request for Comments: 1381 Data General Corporation
F. Baker
Advanced Computer Communications
November 1992
SNMP MIB Extension for X.25 LAPB
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 the Link Layer of
X.25, LAPB. The objects defined here, along with the objects in the
"SNMP MIB Extension for the Packet Layer of X.25" [9] and the
"Definitions of Managed Objects for RS-232-like Hardware Devices"
[8], combine to allow management of an X.25 protocol stack.
Table of Contents
1. The Network Management Framework ....................... 2
2. Objects ................................................ 2
2.1 Format of Definitions ................................. 3
3. Overview ............................................... 3
3.1 Informal overview ..................................... 3
3.2 Textual Conventions ................................... 4
3.3 Formal overview ....................................... 4
3.4 Tables ................................................ 5
3.5 Traps ................................................. 6
4. Object Definitions ..................................... 6
5. Appendix: Revision History ............................. 27
July 30, 1992 .......................................... 27
June 12, 1992 .......................................... 27
May 18, 1992 ........................................... 28
April 8, 1992 .......................................... 28
February 1992 .......................................... 28
October 1991 ........................................... 29
June 1991 .............................................. 30
April 1991 ............................................. 30
Throop & Baker [Page 1]RFC 1381 X.25 LAPB MIB November 1992
6. Acknowledgements ....................................... 30
7. References ............................................. 31
8. Security Considerations ................................ 33
9. Authors' Addresses ..................................... 33
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" [4],
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 RFC 1156 [2] "Management Information Base for Network
Management of TCP/IP-based internets". STD 17/RFC 1213 [5] defines
MIB-II, an evolution of MIB-I with changes to incorporate
implementation experience and new operational requirements.
STD 15/RFC 1157 [3] 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 the
Abstract Syntax Notation One (ASN.1) [6] 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 OBJECT DESCRIPTOR, to also refer to objects.
Objects also have a syntax that defines the abstract data structure
corresponding to that object type. The ASN.1 language [6] provides
Throop & Baker [Page 2]
RFC 1381 X.25 LAPB MIB November 1992
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. The encoding of an object type simply
describes how to represent an object using ASN.1 encoding rules [7],
for purposes of dealing with the SNMP protocol.
2.1. Format of Definitions
Section 4 contains the specification of all object types defined in
this MIB module. The object definitions use the conventions given in
the SMI [1] as amended by the concise MIB definitions [4].
3. Overview
3.1. Informal overview
This section describes how the objects defined below relate with
other MIBs. This section is only informational to help understand
how the pieces fit together.
The objects defined below are to be used in conjunction with MIB-II
and other MIBs such as the X.25 packet level MIB [9]. A system with
a complete X.25 stack running over a synchronous line will have at
least two interfaces in the ifTable defined in MIB-II. There will be
an interface for LAPB and another interface for the packet layer of
X.25. There will also be objects defined in the RS-232-like MIB for
the physical sync line.
Each software interface identifies the layer below it used to send
and receive packets. The X.25 MIB object, x25InfoDataLinkId,
specifies an instance of lapbAdmnIndex for the LAPB interface under
that X.25. The LAPB object, lapbOperPortId, defined below, identifies
an instance of the rs232PortIndex for the the Sync line used by LAPB.
For X.25 running over LAPB over Ethernet, the lapbAdmnPortId would
identify the instance of ifIndex for the Ethernet interface.
Each X.25 subnetwork will have separate entries in the ifTable. Thus
a system with two X.25 lines would have two ifTable entries for the
two X.25 packet layers and two other entries for the two LAPB
interfaces. Each X.25 Packet Layer MIB would identify the instance of
the LAPB MIB below it. Each LAPB MIB would identify the Sync line
below it. The system would also have two entries for rs232PortTable
and rs232SyncPortTable for the two physical lines.
Since the ifTable as defined in MIB-II is device independent, it
doesn't have anything specific for any type of interface. The
objects below define the LAPB specific information for an interface
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RFC 1381 X.25 LAPB MIB November 1992
of type LAPB. Different LAPB interfaces can also be differentiated by
matching the values of ifIndex with lapbAdmnIndex.
3.2. Textual Conventions
Two new data types are introduced as a textual conventions in this
MIB document. These textual conventions enhance the readability of
the specification and can ease comparison with other specifications
if appropriate. It should be noted that the introduction of these
textual conventions has no effect on either the syntax nor the
semantics of any managed objects. The use of these is merely an
artifact of the explanatory method used. Objects defined in terms of
one of these methods are always encoded by means of the rules that
define the primitive type. Hence, no changes to the SMI or the SNMP
are necessary to accommodate these textual conventions which are
adopted merely for the convenience of readers and writers in pursuit
of the elusive goal of clear, concise, and unambiguous MIB documents.
This MIB introduces the data types of:
PositiveInteger
ifIndexType
3.3. Formal overview
Instances of the objects defined below represent attributes of a LAPB
interface. LAPB interfaces are identified by an ifType object in the
Internet-standard MIB [5] of
lapb(16).
For these interfaces, the value of the ifSpecific variable in the
MIB-II [5] has the OBJECT IDENTIFIER value:
lapb OBJECT IDENTIFIER ::= { transmission 16 }
The relationship between a LAPB interface and an interface in the
context of the Internet-standard MIB [5] is one-to-one. As such, the
value of an ifIndex object instance can be directly used to identify
corresponding instances of the objects defined below.
The objects defined below are defined in the context of ISO 7776 [10]
and ISO 8885 [11]. Access to those documents maybe useful (but isn't
essential) to understand the names and semantics of some objects.
Where possible the object descriptions use the terminology of ISO
7776; for example, one commonly used term refers to the peer LAPB as
the DCE/remote DTE. This terminology does not restrict the
instrumented LAPB to function only as a DTE. This MIB maybe applied
Throop & Baker [Page 4]RFC 1381 X.25 LAPB MIB November 1992
to a LAPB configured as either a DCE or a DTE.
To the extent that some attributes defined in the Internet standard
MIB [5] are applicable to LAPB, those objects have not been
duplicated here. In some instances some clarification of how to
apply those objects to LAPB has been given.
Some objects defined below include a DEFVAL clause. This clause
provides reasonable (but not mandatory) default values to use when
creating these objects. This does not imply this MIB defines any
mechanism for creating or deleting LAPB interfaces. The creation and
deletion of the objects of this MIB depend on the implementation
method for creating and deleting LAPB interfaces. The DEFVAL clause
provides reasonable defaults to allow further extension of the MIB to
define methods for creating and deleting LAPB interfaces without
having to deprecate these objects for the lack of a DEFVAL clause.
3.4. Tables
This extension adds four tables to the MIB. These tables are:
lapbAdmnTable,
lapbOperTable,
lapbFlowTable, and
lapbXidTable.
The lapbAdmnTable provides objects for common parameters used by LAPB
such as the T1 retransmission timer or the N2 retransmission counter.
Changes to objects in this table need not affect a running interface
but provides access to the values used to initialize an interface.
These values are read-write.
The lapbOperTable provides objects to determine the parameters
actually in use by an interface. These objects are read only. The
values currently in use maybe different from the lapbAdmnTable values
if the lapbAdmnTable was changed after interface initialization or if
XID negotiation selected different values.
The lapbFlowTable provides objects that report how the LAPB interface
performs. These are read-only objects used to monitor operation.
The lapbXidTable is not required for systems that do not transmit XID
frames. For systems that do transmit XID frames, this table provides
the values for the fields of the XID frame that are not already
present in the lapbAdmnTable. The objects in this table are read-
write.
Throop & Baker [Page 5]RFC 1381 X.25 LAPB MIB November 1992
3.5. Traps
Since all LAPB interfaces have entries in the ifTable, significant
changes in the state of the interface should send a linkUp or
linkDown trap. Thus an interface that receives or sends a Frame
Reject frame should send a linkDown trap. If the interface later
comes back up, it should then send a linkUP trap.
4. Object Definitions
RFC1381-MIB DEFINITIONS ::= BEGIN
IMPORTS
Counter
FROM RFC1155-SMI
transmission
FROM RFC1213-MIB
OBJECT-TYPE
FROM RFC-1212;
-- LAPB MIB
lapb OBJECT IDENTIFIER ::= { transmission 16 }
PositiveInteger ::= INTEGER (0..2147483647)
IfIndexType ::= INTEGER (1..2147483647)
-- IfIndexType specifies an index object for a table
-- with entries that match entries in the MIB-II ifTable.
-- The value of the index for the table will match the
-- ifIndex entry for same interface in the ifTable.
-- The values of this object range from 1 to ifNumber
-- inclusive.
-- ###########################################################
-- LAPB Admn Table
-- ###########################################################
-- Support of the lapbAdmnTable is mandatory for all
-- agents of systems that implement LAPB.
lapbAdmnTable OBJECT-TYPE
SYNTAX SEQUENCE OF LapbAdmnEntry
ACCESS not-accessible
STATUS mandatory
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DESCRIPTION
"This table contains objects that can be
changed to manage a LAPB interface.
Changing one of these parameters may take
effect in the operating LAPB immediately or
may wait until the interface is restarted
depending on the details of the
implementation.
Most of the objects in this read-write table
have corresponding read-only objects in the
lapbOperTable that return the current
operating value.
The operating values may be different from
these configured values if changed by XID
negotiation or if a configured parameter was
changed after the interface was started."
::= { lapb 1 }
lapbAdmnEntry OBJECT-TYPE
SYNTAX LapbAdmnEntry
ACCESS not-accessible
STATUS mandatory
DESCRIPTION
"Configured parameter values for a specific
LAPB."
INDEX { lapbAdmnIndex }
::= { lapbAdmnTable 1 }
LapbAdmnEntry ::= SEQUENCE {
lapbAdmnIndex
IfIndexType,
lapbAdmnStationType
INTEGER,
lapbAdmnControlField
INTEGER,
lapbAdmnTransmitN1FrameSize
PositiveInteger,
lapbAdmnReceiveN1FrameSize
PositiveInteger,
lapbAdmnTransmitKWindowSize
INTEGER,
lapbAdmnReceiveKWindowSize
INTEGER,
lapbAdmnN2RxmitCount
INTEGER,
lapbAdmnT1AckTimer
Throop & Baker [Page 7]RFC 1381 X.25 LAPB MIB November 1992
PositiveInteger,
lapbAdmnT2AckDelayTimer
PositiveInteger,
lapbAdmnT3DisconnectTimer
PositiveInteger,
lapbAdmnT4IdleTimer
PositiveInteger,
lapbAdmnActionInitiate
INTEGER,
lapbAdmnActionRecvDM
INTEGER
}
lapbAdmnIndex OBJECT-TYPE
SYNTAX IfIndexType
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The ifIndex value for the LAPB interface."
::= { lapbAdmnEntry 1 }
lapbAdmnStationType OBJECT-TYPE
SYNTAX INTEGER {
dte (1),
dce (2),
dxe (3)
}
ACCESS read-write
STATUS mandatory
DESCRIPTION
"Identifies the desired station type of this
interface."
REFERENCE "ISO 7776 section 3.1"
DEFVAL { dte }
::= { lapbAdmnEntry 2 }
lapbAdmnControlField OBJECT-TYPE
SYNTAX INTEGER {
modulo8 (1),
modulo128 (2)
}
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The desired size of the sequence numbers
used to number frames."
REFERENCE "ISO 8885 Table 3, Name: HDLC Option - 10"
DEFVAL { modulo8 }
Throop & Baker [Page 8]RFC 1381 X.25 LAPB MIB November 1992
::= { lapbAdmnEntry 3 }
lapbAdmnTransmitN1FrameSize OBJECT-TYPE
SYNTAX PositiveInteger
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The default maximum N1 frame size desired
in number of bits for a frame transmitted by
this DTE. This excludes flags and 0 bits
inserted for transparency."
REFERENCE "ISO 8885 Table 3,
Name: Information Field length"
DEFVAL { 36000 } -- 4500 * 8; 802.5 Frame size
::= { lapbAdmnEntry 4 }
lapbAdmnReceiveN1FrameSize OBJECT-TYPE
SYNTAX PositiveInteger
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The default maximum N1 frame size desired
in number of bits for a frame the DCE/remote
DTE transmits to this DTE. This excludes
flags and 0 bits inserted for transparency."
DEFVAL { 36000 } -- 4500 * 8; 802.5 Frame size
::= { lapbAdmnEntry 5 }
lapbAdmnTransmitKWindowSize OBJECT-TYPE
SYNTAX INTEGER (1..127)
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The default transmit window size for this
Interface. This is the maximum number of
unacknowledged sequenced PDUs that may be
outstanding from this DTE at any one time."
REFERENCE "ISO 8885 Table 3, Name: Window size"
DEFVAL { 7 }
::= { lapbAdmnEntry 6 }
lapbAdmnReceiveKWindowSize OBJECT-TYPE
SYNTAX INTEGER (1..127)
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The default receive window size for this
Interface. This is the maximum number of
Throop & Baker [Page 9]RFC 1381 X.25 LAPB MIB November 1992
unacknowledged sequenced PDUs that may be
outstanding from the DCE/remote DTE at any
one time."
REFERENCE "ISO 8885 Table 3, Name: Window size"
DEFVAL { 7 }
::= { lapbAdmnEntry 7 }
lapbAdmnN2RxmitCount OBJECT-TYPE
SYNTAX INTEGER (0..65535)
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The default N2 retry counter for this
interface. This specifies the number of
times a PDU will be resent after the T1
timer expires without an acknowledgement for
the PDU."
REFERENCE "ISO 8885 Table 3,
Name: Retransmission Attempts"
DEFVAL { 20 }
::= { lapbAdmnEntry 8 }
lapbAdmnT1AckTimer OBJECT-TYPE
SYNTAX PositiveInteger
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The default T1 timer for this interface.
This specifies the maximum time in
Milliseconds to wait for acknowledgment of a
PDU."
REFERENCE "ISO 8885 Table 3, Name:
Acknowledgement timer"
DEFVAL { 3000 }
::= { lapbAdmnEntry 9 }
lapbAdmnT2AckDelayTimer OBJECT-TYPE
SYNTAX PositiveInteger
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The default T2 timer for this interface.
This specifies the maximum time in
Milliseconds to wait before sending an
acknowledgment for a sequenced PDU. A value
of zero means there will be no delay in
acknowledgement generation."
REFERENCE "ISO 8885 Table 3,
Throop & Baker [Page 10]RFC 1381 X.25 LAPB MIB November 1992
Name: Reply delay timer"
DEFVAL { 0 }
::= { lapbAdmnEntry 10 }
lapbAdmnT3DisconnectTimer OBJECT-TYPE
SYNTAX PositiveInteger
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The T3 timer for this interface. This
specifies the time in Milliseconds to wait
before considering the link disconnected. A
value of zero indicates the link will be
considered disconnected upon completion of
the frame exchange to disconnect the link."
REFERENCE "ISO 7776 section 5.7.1.3"
DEFVAL { 60000 }
::= { lapbAdmnEntry 11 }
lapbAdmnT4IdleTimer OBJECT-TYPE
SYNTAX PositiveInteger
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The T4 timer for this interface. This
specifies the maximum time in Milliseconds
to allow without frames being exchanged on
the data link. A value of 2147483647
indicates no idle timer is being kept."
REFERENCE "ISO 7776 section 5.7.1.4"
DEFVAL { 2147483647 }
::= { lapbAdmnEntry 12 }
lapbAdmnActionInitiate OBJECT-TYPE
SYNTAX INTEGER {
sendSABM (1),
sendDISC (2),
sendDM (3),
none (4),
other (5)
}
ACCESS read-write
STATUS mandatory
DESCRIPTION
"This identifies the action LAPB will take
to initiate link set-up."
DEFVAL { sendSABM }
::= { lapbAdmnEntry 13 }
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lapbAdmnActionRecvDM OBJECT-TYPE
SYNTAX INTEGER {
sendSABM (1),
sendDISC (2),
other (3)
}
ACCESS read-write
STATUS mandatory
DESCRIPTION
"This identifies the action LAPB will take
when it receives a DM response."
DEFVAL { sendSABM }
::= { lapbAdmnEntry 14 }
-- ###########################################################
-- LAPB operating parameters.
-- ###########################################################
-- Support of the lapbOperTable is mandatory for all
-- agents of systems that implement LAPB.
lapbOperTable OBJECT-TYPE
SYNTAX SEQUENCE OF LapbOperEntry
ACCESS not-accessible
STATUS mandatory
DESCRIPTION
"This table contains configuration
information about interface parameters
currently set in the interface. Many of
these objects have corresponding objects in
the lapbAdmnTable."
::= { lapb 2 }
lapbOperEntry OBJECT-TYPE
SYNTAX LapbOperEntry
ACCESS not-accessible
STATUS mandatory
DESCRIPTION
"Currently set parameter values for a
specific LAPB."
INDEX { lapbOperIndex }
::= { lapbOperTable 1 }
LapbOperEntry ::= SEQUENCE {
lapbOperIndex
IfIndexType,
lapbOperStationType
Throop & Baker [Page 12]RFC 1381 X.25 LAPB MIB November 1992
INTEGER,
lapbOperControlField
INTEGER,
lapbOperTransmitN1FrameSize
PositiveInteger,
lapbOperReceiveN1FrameSize
PositiveInteger,
lapbOperTransmitKWindowSize
INTEGER,
lapbOperReceiveKWindowSize
INTEGER,
lapbOperN2RxmitCount
INTEGER,
lapbOperT1AckTimer
PositiveInteger,
lapbOperT2AckDelayTimer
PositiveInteger,
lapbOperT3DisconnectTimer
PositiveInteger,
lapbOperT4IdleTimer
PositiveInteger,
lapbOperPortId
OBJECT IDENTIFIER,
lapbOperProtocolVersionId
OBJECT IDENTIFIER
}
lapbOperIndex OBJECT-TYPE
SYNTAX IfIndexType
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The ifIndex value for the LAPB interface."
::= { lapbOperEntry 1 }
lapbOperStationType OBJECT-TYPE
SYNTAX INTEGER {
dte (1),
dce (2),
dxe (3)
}
ACCESS read-only
STATUS mandatory
DESCRIPTION
"Identifies the current operating station
type of this interface. A value of dxe (3)
indicates XID negotiation has not yet taken
place."
Throop & Baker [Page 13]RFC 1381 X.25 LAPB MIB November 1992
REFERENCE "ISO 7776 section 3.1"
::= { lapbOperEntry 2 }
lapbOperControlField OBJECT-TYPE
SYNTAX INTEGER {
modulo8 (1),
modulo128 (2)
}
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The current operating size of the sequence
numbers used to number frames."
REFERENCE "ISO 7776 section 3.3"
::= { lapbOperEntry 3 }
lapbOperTransmitN1FrameSize OBJECT-TYPE
SYNTAX PositiveInteger
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The current operating N1 frame size used
for the maximum number of bits in a frame
this DTE can transmit. This excludes flags
and 0 bits inserted for transparency."
REFERENCE "ISO 7776 section 5.7.3"
::= { lapbOperEntry 4 }
lapbOperReceiveN1FrameSize OBJECT-TYPE
SYNTAX PositiveInteger
ACCESS read-only
STATUS mandatory
-- See lapbOperTransmitN1FrameSize above
DESCRIPTION
"The current operating N1 frame size used
for the maximum number of bits in a frame
the DCE/remote DTE can transmit. This
excludes flags and 0 bits inserted for
transparency."
::= { lapbOperEntry 5 }
lapbOperTransmitKWindowSize OBJECT-TYPE
SYNTAX INTEGER (1..127)
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The current PDU window size this Interface
uses to transmit. This is the maximum
Throop & Baker [Page 14]RFC 1381 X.25 LAPB MIB November 1992
number of unacknowledged sequenced PDUs that
may be outstanding from this DTE at any one
time."
REFERENCE "ISO 7776 section 5.7.4"
::= { lapbOperEntry 6 }
lapbOperReceiveKWindowSize OBJECT-TYPE
SYNTAX INTEGER (1..127)
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The current receive PDU window size for
this Interface. This is the maximum number
of unacknowledged sequenced PDUs that may be
outstanding from the DCE/remote DTE at any
one time."
REFERENCE "ISO 7776 section 5.7.4"
::= { lapbOperEntry 7 }
lapbOperN2RxmitCount OBJECT-TYPE
SYNTAX INTEGER (0..65535)
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The current N2 retry counter used for this
interface. This specifies the number of
times a PDU will be resent after the T1
timer expires without an acknowledgement for
the PDU."
REFERENCE "ISO 7776 section 5.7.2"
::= { lapbOperEntry 8 }
lapbOperT1AckTimer OBJECT-TYPE
SYNTAX PositiveInteger
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The current T1 timer for this interface.
This specifies the maximum time in
Milliseconds to wait for acknowledgment of a
PDU."
REFERENCE "ISO 7776 section 5.7.1.1"
::= { lapbOperEntry 9 }
lapbOperT2AckDelayTimer OBJECT-TYPE
SYNTAX PositiveInteger
ACCESS read-only
STATUS mandatory
Throop & Baker [Page 15]RFC 1381 X.25 LAPB MIB November 1992
DESCRIPTION
"The current T2 timer for this interface.
This specifies the maximum time in
Milliseconds to wait before sending an
acknowledgment for a sequenced PDU. A value
of zero means there will be no delay in
acknowledgement generation."
REFERENCE "ISO 7776 section 5.7.1.2"
::= { lapbOperEntry 10 }
lapbOperT3DisconnectTimer OBJECT-TYPE
SYNTAX PositiveInteger
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The current T3 timer for this interface.
This specifies the time in Milliseconds to
wait before considering the link
disconnected. A value of zero indicates the
link will be considered disconnected upon
completion of the frame exchange to
disconnect the link."
REFERENCE "ISO 7776 section 5.7.1.3"
::= { lapbOperEntry 11 }
lapbOperT4IdleTimer OBJECT-TYPE
SYNTAX PositiveInteger
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The current T4 timer for this interface.
This specifies the maximum time in
Milliseconds to allow without frames being
exchanged on the data link. A value of
2147483647 indicates no idle timer is being
kept."
REFERENCE "ISO 7776 section 5.7.1.4"
::= { lapbOperEntry 12 }
lapbOperPortId OBJECT-TYPE
SYNTAX OBJECT IDENTIFIER
ACCESS read-only
STATUS mandatory
DESCRIPTION
"This object identifies an instance of the
index object in the first group of objects
in the MIB specific to the physical device
or interface used to send and receive
Throop & Baker [Page 16]RFC 1381 X.25 LAPB MIB November 1992
frames. If an agent does not support any
such objects, it should return nullSpec
OBJECT IDENTIFIER {0 0}."
::= { lapbOperEntry 13 }
lapbOperProtocolVersionId OBJECT-TYPE
SYNTAX OBJECT IDENTIFIER
ACCESS read-only
STATUS mandatory
DESCRIPTION
"This object identifies the version of the
lapb protocol implemented by this
interface."
::= { lapbOperEntry 14 }
-- ###########################################################
-- LAPB Flow Table
-- ###########################################################
-- Support of the lapbFlowTable is mandatory for all
-- agents of systems that implement LAPB.
lapbFlowTable OBJECT-TYPE
SYNTAX SEQUENCE OF LapbFlowEntry
ACCESS not-accessible
STATUS mandatory
DESCRIPTION
"This table defines the objects recorded by
LAPB to provide information about the
traffic flow through the interface."
::= { lapb 3 }
lapbFlowEntry OBJECT-TYPE
SYNTAX LapbFlowEntry
ACCESS not-accessible
STATUS mandatory
DESCRIPTION
"The information regarding the effects of
flow controls in LAPB."
INDEX { lapbFlowIfIndex }
::= { lapbFlowTable 1 }
LapbFlowEntry ::= SEQUENCE {
lapbFlowIfIndex
IfIndexType,
lapbFlowStateChanges
Counter,
Throop & Baker [Page 17]RFC 1381 X.25 LAPB MIB November 1992
lapbFlowChangeReason
INTEGER,
lapbFlowCurrentMode
INTEGER,
lapbFlowBusyDefers
Counter,
lapbFlowRejOutPkts
Counter,
lapbFlowRejInPkts
Counter,
lapbFlowT1Timeouts
Counter,
lapbFlowFrmrSent
OCTET STRING,
lapbFlowFrmrReceived
OCTET STRING,
lapbFlowXidReceived
OCTET STRING
}
lapbFlowIfIndex OBJECT-TYPE
SYNTAX IfIndexType
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The ifIndex value for the LAPB Interface."
::= { lapbFlowEntry 1 }
lapbFlowStateChanges OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The number of LAPB State Changes, including
resets."
::= { lapbFlowEntry 2 }
lapbFlowChangeReason OBJECT-TYPE
SYNTAX INTEGER {
notStarted (1), -- Initial state
abmEntered (2), -- SABM or UA
abmeEntered (3), -- SABME or UA
abmReset (4), -- SABM in ABM
abmeReset (5), -- SABME in ABME
dmReceived (6), -- DM Response
dmSent (7), -- DM sent
discReceived (8), -- DISC Response
discSent (9), -- DISC Sent
Throop & Baker [Page 18]RFC 1381 X.25 LAPB MIB November 1992
frmrReceived (10), -- FRMR Received
frmrSent (11), -- FRMR Sent
n2Timeout (12), -- N2 Timer Expired
other (13)
}
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The reason for the most recent incrementing
of lapbFlowStateChanges. A DM or DISC frame
generated to initiate link set-up does not
alter this object. When the MIB-II object
ifOperStatus does not have a value of
testing, there exists a correlation between
this object and ifOperStatus. IfOperStatus
will have a value of up when this object
contains: abmEntered, abmeEntered,
abmReset, or abmeReset. IfOperStatus will
have a value of down when this object has a
value of notStarted, or dmReceived through
n2Timeout. There is no correlation when
this object has the value other."
::= { lapbFlowEntry 3 }
lapbFlowCurrentMode OBJECT-TYPE
SYNTAX INTEGER {
disconnected (1),
-- initial state or DISC received
linkSetup (2),
-- SABM sent
frameReject (3),
-- Invalid frame received and
-- FRMR sent
disconnectRequest (4),
-- DISC sent
informationTransfer (5),
-- normal information transfer state
-- SABM(E) sent and UA received, or
-- SABM(E) received and UA sent
rejFrameSent (6),
-- invalid NS received and REJ sent
waitingAcknowledgement (7),
Throop & Baker [Page 19]RFC 1381 X.25 LAPB MIB November 1992
-- T1 expired and RR sent
stationBusy (8),
-- RNR sent
remoteStationBusy (9),
-- RNR received
bothStationsBusy (10),
-- RNR received and RNR sent
waitingAckStationBusy (11),
-- T1 expired, RNR sent
waitingAckRemoteBusy (12),
-- T1 expired, RNR received
waitingAckBothBusy (13),
-- T1 expired, RNR sent,
-- and RNR received
rejFrameSentRemoteBusy (14),
-- REJ sent and RNR received
xidFrameSent (15),
-- XID frame sent
error (16),
-- An error state other than
-- a one defined above
other (17)
-- A state not listed above
}
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The current condition of the conversation."
::= { lapbFlowEntry 4 }
lapbFlowBusyDefers OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The number of times this device was unable
to transmit a frame due to a perceived
remote busy condition. Busy conditions can
Throop & Baker [Page 20]RFC 1381 X.25 LAPB MIB November 1992
result from the receipt of an RNR from the
remote device, the lack of valid sequence
number space (window saturation), or other
conditions."
::= { lapbFlowEntry 5 }
lapbFlowRejOutPkts OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The number of REJ or SREJ frames sent by
this station."
::= { lapbFlowEntry 6 }
lapbFlowRejInPkts OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The number of REJ or SREJ frames received
by this station."
::= { lapbFlowEntry 7 }
lapbFlowT1Timeouts OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The number of times a re-transmission was
effected by the T1 Timer expiring."
::= { lapbFlowEntry 8 }
lapbFlowFrmrSent OBJECT-TYPE
SYNTAX OCTET STRING (SIZE (0..7))
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The Information Field of the FRMR most
recently sent. If no FRMR has been sent
(the normal case) or the information isn't
available, this will be an OCTET STRING of
zero length."
REFERENCE "ISO 7776 Section 4.3.9, tables 7 and 8"
::= { lapbFlowEntry 9 }
lapbFlowFrmrReceived OBJECT-TYPE
SYNTAX OCTET STRING (SIZE (0..7))
Throop & Baker [Page 21]RFC 1381 X.25 LAPB MIB November 1992
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The Information Field of the FRMR most
recently received. If no FRMR has been
received (the normal case) or the
information isn't available, this will be an
OCTET STRING of zero length."
REFERENCE "ISO 7776 Section 4.3.9, tables 7 and 8"
::= { lapbFlowEntry 10 }
lapbFlowXidReceived OBJECT-TYPE
SYNTAX OCTET STRING (SIZE (0..8206))
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The Information Field of the XID frame most
recently received. If no XID frame has been
received, this will be an OCTET STRING of
zero length."
REFERENCE "ISO 8885"
::= { lapbFlowEntry 11 }
-- ###########################################################
-- LAPB XID Table
-- ###########################################################
-- Support for the lapbXidTable is mandatory for all agents
-- of systems that have a LAPB implementation using XID
-- negotiation. Agents of systems without XID negotiation
-- support should not implement this table.
lapbXidTable OBJECT-TYPE
SYNTAX SEQUENCE OF LapbXidEntry
ACCESS not-accessible
STATUS mandatory
DESCRIPTION
"This table defines values to use for XID
negotiation that are not found in the
lapbAdmnTable. This table is optional for
implementations that don't support XID and
mandatory for implementations that do
initiate XID negotiation."
::= { lapb 4 }
lapbXidEntry OBJECT-TYPE
SYNTAX LapbXidEntry
Throop & Baker [Page 22]RFC 1381 X.25 LAPB MIB November 1992
ACCESS not-accessible
STATUS mandatory
DESCRIPTION
"XId negotiation parameter values for a
specific LAPB."
INDEX { lapbXidIndex }
::= { lapbXidTable 1 }
LapbXidEntry ::= SEQUENCE {
lapbXidIndex
IfIndexType,
lapbXidAdRIdentifier
OCTET STRING,
lapbXidAdRAddress
OCTET STRING,
lapbXidParameterUniqueIdentifier
OCTET STRING,
lapbXidGroupAddress
OCTET STRING,
lapbXidPortNumber
OCTET STRING,
lapbXidUserDataSubfield
OCTET STRING
}
lapbXidIndex OBJECT-TYPE
SYNTAX IfIndexType
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The ifIndex value for the LAPB interface."
::= { lapbXidEntry 1 }
lapbXidAdRIdentifier OBJECT-TYPE
SYNTAX OCTET STRING (SIZE (0..255))
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The value of the Address Resolution
Identifier. A zero length string indicates
no Identifier value has been assigned."
REFERENCE "ISO 8885 Table 2, Name: Identifier"
DEFVAL { ''h }
::= { lapbXidEntry 2 }
lapbXidAdRAddress OBJECT-TYPE
SYNTAX OCTET STRING (SIZE (0..255))
Throop & Baker [Page 23]RFC 1381 X.25 LAPB MIB November 1992
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The value of the Address Resolution
Address. A zero length string indicates no
Address value has been assigned."
REFERENCE "ISO 8885 Table 2, Name: Address"
DEFVAL { ''h }
::= { lapbXidEntry 3 }
lapbXidParameterUniqueIdentifier OBJECT-TYPE
SYNTAX OCTET STRING (SIZE (0..255))
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The value of the parameter unique
Identifier. A zero length string indicates
no Unique identifier value has been
assigned."
REFERENCE "ISO 8885 Table 3, Name: Identifier"
DEFVAL { ''h }
::= { lapbXidEntry 4 }
lapbXidGroupAddress OBJECT-TYPE
SYNTAX OCTET STRING (SIZE (0..255))
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The value of the parameter Group address.
A zero length string indicates no Group
address value has been assigned."
REFERENCE "ISO 8885 Table 3, Name: Group address"
DEFVAL { ''h }
::= { lapbXidEntry 5 }
lapbXidPortNumber OBJECT-TYPE
SYNTAX OCTET STRING (SIZE (0..255))
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The port number assigned for this link. A
zero length string indicates no local port
number identifier has been assigned."
REFERENCE "ISO 8885 Table 3, Name: Port number"
DEFVAL { ''h }
::= { lapbXidEntry 6 }
lapbXidUserDataSubfield OBJECT-TYPE
Throop & Baker [Page 24]RFC 1381 X.25 LAPB MIB November 1992
SYNTAX OCTET STRING (SIZE (0..8206))
ACCESS read-write
STATUS mandatory
DESCRIPTION
"A user data subfield, if any, to be
transmitted in an XID frame. A zero length
frame indicates no user data subfield has
been assigned. The octet string should
include both the User data identifier and
User data field as shown in Figures 1 and
4."
REFERENCE "ISO 8885 section 4.3"
DEFVAL { ''h }
::= { lapbXidEntry 7 }
-- ###########################################################
-- LAPB protocol versions
-- ###########################################################
lapbProtocolVersion OBJECT IDENTIFIER
::= { lapb 5 }
lapbProtocolIso7776v1986 OBJECT IDENTIFIER
::= { lapbProtocolVersion 1 }
lapbProtocolCcittV1980 OBJECT IDENTIFIER
::= { lapbProtocolVersion 2 }
lapbProtocolCcittV1984 OBJECT IDENTIFIER
::= { lapbProtocolVersion 3 }
-- The following describes some of the MIB-II interface
-- objects and their relationship with the objects in this
-- MIB extension.
-- ifDescr: describes the interface. It should include
-- identification information for the physical line and a
-- description of the network. For connections to PDNs,
-- it should name the PDN.
-- ifMtu: the maximum number of octets an upper layer can
-- pass to this interface as a single frame.
-- ifSpeed:
Throop & Baker [Page 25]RFC 1381 X.25 LAPB MIB November 1992
-- ifAdminStatus:
-- ifOperStatus:
-- ifLastChange: the last time the state of the interface
-- changed. A reset is considered an instantaneous change to
-- the ndm state and back to abm or abme. This will be the
-- last time that lapbFlowChangeReason and lapbFlowChanges
-- changed.
-- ifInOctets: contains the number of octets
-- received from the peer LAPB including FCS.
-- ifInUcastPkts: contains the number of I-frames delivered
-- by this interface to a higher layer interface.
-- ifInDiscards: contains the number of received
-- frames discarded because of internal conditions
-- (such as lack of buffering).
-- ifInErrors: contains the number of Invalid frames received.
-- This does not have any relationship with the number REJ,
-- or RNR frames sent or received.
-- ifInUnknownProtos: contains the number of frames
-- that were correct but were dropped because they
-- were inappropriate for the current state. This
-- includes an invalid Poll bit, an unknown address,
-- or other condition such as an RNR when connection
-- not established. This also includes the number of
-- DISC or other frames that were ignored because the
-- link was not established and this interface was not
-- configured to perform link setup on that type frame.
-- ifOutOctets: number of octets sent to peer including
-- FCS octets.
-- ifOutUcastPkts: number of I-frames received from
-- a higher layer for transmission to peer.
-- ifOutDiscards: number of frames to be sent that were
-- dropped due to internal conditions such as buffering etc.
-- ifOutErrors: number of transmissions that failed
-- due to errors or were considered invalid by the receiver.
-- This does not have any relationship with the number REJ,
-- or RNR frames sent or received.
Throop & Baker [Page 26]RFC 1381 X.25 LAPB MIB November 1992
-- ifOutQLen: number of frames waiting to be transmitted.
-- This MIB does not provide any support for:
-- Multilink procedure (MLP) in ISO 7776 section 6
-- LLC Pbit timer
-- LLC REJ timer
-- LLC Busy State Timer 7.8.1.4
-- ###########################################################
END
5. Appendix: Revision History
July 30, 1992
The July revision of this document (Editor's Internal Reference 2.10)
incorporated the comments of the SNMP directorate.
The ifIndexType textual convention was added and used as the type
for all index objects.
The enumeration xidDetection of the lapbAdmnStationType was
changed to dxe to be consistent with other similar enumerations.
Conformance statements were added at before every table as ASN.1
comments.
June 12, 1992
The June 12, 1992 revision of this document (Editor's Internal
Reference 2.9) incorporated some clarifications and updated the
status.
The range on PositiveInteger was changed to start at 0 rather than
1.
The syntax of lapbXidIndex was changed to PositiveInteger.
A value of dxe was added to lapbOperStationType.
The range of lapbAdmnN2RxmitCount was change to (0..65535).
The definition of ifInOctets, ifInUcastPkts, ifInErrors,
ifInUnknownProtos, ifOutOctets, and ifoutUcastPkts was clarified.
Throop & Baker [Page 27]RFC 1381 X.25 LAPB MIB November 1992
May 18, 1992
The May 18, 1992 revision of this document (Editor's Internal
Reference 2.8) incorporated the following changes:
The states of lapbFlowCurrentMode were redefined.
The default value for lapbAdmnControlField was changed from
module8 to modulo8.
April 8, 1992
The April 8, 1992 revision of this document (Editor's Internal
Reference 2.4) incorporated the following changes:
All reference comments in the MIB were moved to the REFERENCE
field of the OBJECT-TYPE macro.
A type of PositiveInteger was introduced and used for common
integer values including all timers. This effectively made the
maximum value for timers 2147483646 milliseconds. The type of the
frame size was changed to positiveInteger.
The reference to ISO 7776 has been broadened to say the MIB
descriptions use the terminology of ISO 7776.
A comment was added to the overview section discussing creation
and deletion of tables.
The objects in the lapbParmTable and lapbDefTable were
redistributed to create a lapbOperTable, a lapbAdmnTable, and a
lapbXidTable. The lapbParmTable and lapbDefTable were deleted.
Objects were included in the Admn table for t3 and t4.
An object identifier was added to identify the protocol version.
A DEFVAL clause was added for all writable objects.
Some more overview text was included.
February 1992
The February 1992 revision of this document (Editor's Internal
Reference 1.17) incorporated the following changes:
The name was changed from HDLC to LAPB. This change was made
because other flavors of HDLC such as LAPD, SDLC, and raw HDLC
framing, are different enough that this MIB will not adequately
Throop & Baker [Page 28]RFC 1381 X.25 LAPB MIB November 1992
manage them.
The Historical Perspective section at the beginning of the
document has been replaced with a more concise Network Management
Framework section.
The name lapbParmKWindowSize was changed to
lapbParmTransmitKWindowSize and the object
lapbParmReceiveKWindowSize was added. This change was made because
section 5.7.4 of ISO 7776 and Table 3 of ISO 8885 have provisions
for different values for the transmit and receive window size.
The name lapbParmN1FrameSize was changed to
lapbParmTransmitN1FrameSize and the object
lapbParmReceiveN1FrameSize was added. This change was made because
section 5.7.3 of ISO 7776 and Table 3 of ISO 8886 have provisions
for different values for the transmit and receive maximum frame
size.
The object lapbParmPortIndex was deleted and the description of
lapbParmPortId was changed. The object lapbParmPortId now
identifies an instance of the index object for the MIB of the
physical device or interface below LAPB.
The units for the timers were changed to Milliseconds to be
consistent with ISO 8885; see table 3.
The objects lapbParamT2AckDelayTimer and
lapbParamT3DisconnectTimer both allow values of 0 to indicate the
timer is not being used.
The object lapbParamT4IdleTimer has a value to indicate timer not
in use.
The object lapbFlowXidReceived was added to the flow table.
The lapbDefTable was added.
Ranges and sizes were added for all INTEGERs and OCTET STRINGs
that didn't have them.
October 1991
The October 1991 revision of this document basically changed the name
from LAPB to HDLC to make the objects more appropriate for a broader
range of uses. A number of minor changes were made to bring the
objects in line with established conventions. These changes are as
follows.
Throop & Baker [Page 29]RFC 1381 X.25 LAPB MIB November 1992
The enumerated values of hdlcParmStationType were renumbered from
0 and 1 to 1 and 2.
The object hdlcFlowBusyDefer was renamed hdlcFlowBusyDefers.
The object hdlcFlowRejSent was rename hdlcFlowRejOutPkts.
The object hdlcFlowRejReceived was renamed hdlcFlowRejInPkts.
June 1991
The June revision of this document incorporated much of the E-mail
discussion of the first draft. In particular it replaced the
lapbStatTable (and all contents) with the lapbFlowTable.
April 1991
The April 24 version of this document was the first release. At that
time this document was basically a bunch of objects synthesized from
various vendor MIBs and a quick reading of ISO 7776 [10]. On first
reading it appeared to instrument too many LAPB normal functions and
too few exceptional conditions. The lapbStatTable was too long and
needed to be redone.
6. 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, Snmp Research
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, Process Software Corporation
Throop & Baker [Page 30]RFC 1381 X.25 LAPB MIB November 1992
Jon Infante, ICL
Frank Kastenholz, Clearpoint
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
In addition, the comments of the following individuals are also
acknowledged:
Keith McCloghrie
7. 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] McCloghrie K., and M. Rose, "Management Information Base for
Network Management of TCP/IP-based internets", RFC 1156, Hughes
LAN Systems, Performance Systems International, May 1990.
[3] Case, J., Fedor, M., Schoffstall, M., and J. Davin, "Simple
Throop & Baker [Page 31]RFC 1381 X.25 LAPB MIB November 1992
Network Management Protocol", STD 15, RFC 1157, SNMP Research,
Performance Systems International, Performance Systems
International, MIT Laboratory for Computer Science, May 1990.
[4] Rose, M., and K. McCloghrie, Editors, "Concise MIB Definitions",
STD 16, RFC 1212, Performance Systems International, Hughes LAN
Systems, March 1991.
[5] Rose M., Editor, "Management Information Base for Network
Management of TCP/IP-based internets: MIB-II", STD 17, RFC 1213,
Performance Systems International, March 1991.
[6] Information processing systems - Open Systems Interconnection -
Specification of Abstract Syntax Notation One (ASN.1),
International Organization for Standardization, International
Standard 8824, December 1987.
[7] Information processing systems - Open Systems Interconnection -
Specification of Basic Encoding Rules for Abstract Notation One
(ASN.1), International Organization for Standardization,
International Standard 8825, December 1987.
[8] Stewart, B., Editor, "Definitions of Managed Objects for RS-232-
like Hardware Devices", RFC 1317, Xyplex, Inc., April 1992.
[9] Throop, D., Editor, "SNMP MIB extension for the Packet Layer of
X.25", RFC 1382, Data General Corporation, November 1992.
[10] "Information processing systems - Data communication - High-level
data link control procedure - Description of the X.25 LAPB-
compatible DTE data link procedures", International Organization
for Standardization, International Standard 7776, December 1986.
[11] "Information technology - Telecommunications and information
exchange between systems - High-level data link control (HDLC)
procedures - General purpose XID frame information field contents
and format", International Organization for Standardization,
International Standard 8885.
Throop & Baker [Page 32]RFC 1381 X.25 LAPB MIB November 1992
8. Security Considerations
Security issues are not discussed in this memo.
9. Authors' Addresses
Dean D. Throop
Data General Corporation
62 Alexander Dr.
Research Triangle Park, NC 27709
Phone: (919)248-8421
EMail: throop@dg-rtp.dg.com
Fred Baker
Advanced Computer Communications
315 Bollay Drive
Santa Barbara, CA 93101
Phone: (805) 685-4455
EMail: fbaker@acc.com
While the working group has completed discussion of this document,
comments are still welcome. Please send comments to the x25mib
working group at: x25mib@dg-rtp.dg.com
Throop & Baker [Page 33]
