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Draft Textual Conventions for SNMPv2 Dec 92
Textual Conventions
for version 2 of the
Simple Network Management Protocol (SNMPv2)
Tue Dec 22 13:43:46 1992 |
Jeffrey D. Case
SNMP Research, Inc.
University of Tennessee, Knoxville
case@cs.utk.edu
Keith McCloghrie
Hughes LAN Systems
kzm@hls.com
Marshall T. Rose
Dover Beach Consulting, Inc.
mrose@dbc.mtview.ca.us
Steven L. Waldbusser
Carnegie Mellon University
waldbusser@andrew.cmu.edu
Status of this Memo
This document is an Internet Draft. Internet Drafts are
working documents of the Internet Engineering Task Force
(IETF), its Areas, and its Working Groups. Note that other
groups may also distribute working documents as Internet
Drafts.
Internet Drafts are valid for a maximum of six months and may
be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet Drafts as reference
material or to cite them other than as a "work in progress".
Expires June 22, 1993 [Page 1]
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1. Introduction
A network management system contains: several (potentially
many) nodes, each with a processing entity, termed an agent,
which has access to management instrumentation; at least one
management station; and, a management protocol, used to convey
management information between the agents and management
stations. Operations of the protocol are carried out under an
administrative framework which defines both authentication and
authorization policies.
Network management stations execute management applications
which monitor and control network elements. Network elements
are devices such as hosts, routers, terminal servers, etc.,
which are monitored and controlled through access to their
management information.
Management information is viewed as a collection of managed
objects, residing in a virtual information store, termed the
Management Information Base (MIB). Collections of related
objects are defined in MIB modules. These modules are written
using a subset of OSI's Abstract Syntax Notation One (ASN.1)
[1], termed the Structure of Management Information (SMI) [2].
When designing a MIB module, it is often useful to new define
types similar to those defined in the SMI. In comparison to a
type defined in the SMI, each of these new types has a
different name, a similar syntax, but a more precise
semantics. These newly defined types are termed textual
conventions, and are used for the convenience of humans
reading the MIB module. It is the purpose of this document to
define the initial set of textual conventions available to all
MIB modules.
Objects defined using a textual convention are always encoded
by means of the rules that define their primitive type.
However, textual conventions often have special semantics
associated with them. As such, an ASN.1 macro, TEXTUAL-
CONVENTION, is used to concisely convey the syntax and
semantics of a textual convention.
For all textual conventions defined in an information module,
the name shall be unique and mnemonic, and shall not exceed 64
characters in length. All names used for the textual
conventions defined in all "standard" information modules
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shall be unique.
1.1. A Note on Terminology
For the purpose of exposition, the original Internet-standard
Network Management Framework, as described in RFCs 1155, 1157,
and 1212, is termed the SNMP version 1 framework (SNMPv1).
The current framework is termed the SNMP version 2 framework
(SNMPv2).
Expires June 22, 1993 [Page 3]
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2. Definitions
SNMPv2-TC DEFINITIONS ::= BEGIN
IMPORTS
ObjectSyntax, Integer32, TimeTicks
FROM SNMPv2-SMI;
-- definition of textual conventions
TEXTUAL-CONVENTION MACRO ::=
BEGIN
TYPE NOTATION ::=
DisplayPart
"STATUS" Status
"DESCRIPTION" Text
ReferPart
"SYNTAX" type(Syntax)
VALUE NOTATION ::=
value(VALUE Syntax)
DisplayPart ::=
"DISPLAY-HINT" Text
| empty
Status ::=
"current"
| "deprecated"
| "obsolete"
ReferPart ::=
"REFERENCE" Text
| empty
-- uses the NVT ASCII character set
Text ::= """" string """"
END
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DisplayString ::= TEXTUAL-CONVENTION
DISPLAY-HINT "255a"
STATUS current
DESCRIPTION
"Represents textual information taken from the NVT
ASCII character set, as defined in pages 4, 10-11
of RFC 854. Any object defined using this syntax
may not exceed 255 characters in length."
SYNTAX OCTET STRING
PhysAddress ::= TEXTUAL-CONVENTION
DISPLAY-HINT "1x:"
STATUS current
DESCRIPTION
"Represents media- or physical-level addresses."
SYNTAX OCTET STRING
MacAddress ::= TEXTUAL-CONVENTION
DISPLAY-HINT "1x:"
STATUS current
DESCRIPTION
"Represents an 802 MAC address represented in the
`canonical' order defined by IEEE 802.1a, i.e., as
if it were transmitted least significant bit
first, even though 802.5 (in contrast to other
802.x protocols) requires MAC addresses to be
transmitted most significant bit first."
SYNTAX OCTET STRING (SIZE (6))
TruthValue ::= TEXTUAL-CONVENTION
STATUS current
DESCRIPTION
"Represents a boolean value."
SYNTAX INTEGER { true(1), false(2) }
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TestAndIncr ::= TEXTUAL-CONVENTION
STATUS current
DESCRIPTION
"Represents integer-valued information used for
atomic operations. When the management protocol
is used to specify that an object instance having
this syntax is to be modified, the new value
supplied via the management protocol must
precisely match the value presently held by the
instance. If not, the management protocol set
operation fails with an error of
`inconsistentValue'. Otherwise, if the current
value is the maximum value of 2^31-1 (2147483647
decimal), then the value held by the instance is
wrapped to zero; otherwise, the value held by the
instance is incremented by one. (Note that
regardless of whether the management protocol set
operation succeeds, the variable-binding in the
request and response PDUs are identical.)
The value of the ACCESS clause for objects having
this syntax is either `read-write' or `read-
create'. When an instance of a columnar object
having this syntax is created, any value may be
supplied via the management protocol."
SYNTAX INTEGER (0..2147483647)
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AutonomousType ::= TEXTUAL-CONVENTION
STATUS current
DESCRIPTION
"Represents an independently extensible type
identification value. It may, for example,
indicate a particular sub-tree with further MIB
definitions, or define a particular type of
protocol or hardware."
SYNTAX OBJECT IDENTIFIER
InstancePointer ::= TEXTUAL-CONVENTION
STATUS current
DESCRIPTION
"A pointer to a specific instance of a conceptual
row of a MIB table in the managed device. By
convention, it is the name of the particular
instance of the first columnar object in the
conceptual row."
SYNTAX OBJECT IDENTIFIER
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RowStatus ::= TEXTUAL-CONVENTION
STATUS current
DESCRIPTION
"The RowStatus textual convention is used to |
manage the creation and deletion of conceptual |
rows, and is used as the value of the SYNTAX |
clause for the status column of a conceptual row |
(as described in Section 7.7.1 of [2].) |
The status column has six defined values: |
- `active', which indicates that the |
conceptual row is available for use by the |
managed device; |
- `notInService', which indicates that the |
conceptual row exists in the agent, but is |
unavailable for use by the managed device |
(see NOTE below); |
- `notReady', which indicates that the |
conceptual row exists in the agent, but is |
missing information necessary in order to be |
available for use by the managed device; |
- `createAndGo', which is supplied by a |
management station wishing to create a new |
instance of a conceptual row and to have it |
available for use by the managed device; |
- `createAndWait', which is supplied by a |
management station wishing to create a new |
instance of a conceptual row but not to have |
it available for use by the managed device; |
and, |
- `destroy', which is supplied by a |
management station wishing to delete all of |
the instances associated with an existing |
conceptual row. |
Whereas five of the six values (all except |
`notReady') may be specified in a management |
protocol set operation, only three values will be |
returned in response to a management protocol |
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retrieval operation: `notReady', `notInService' or |
`active'. That is, when queried, an existing |
conceptual row has only three states: it is either |
available for use by the managed device (the |
status column has value `active'); it is not |
available for use by the managed device, though |
the agent has sufficient information to make it so |
(the status column has value `notInService'); or, |
it is not available for use by the managed device, |
because the agent lacks sufficient information |
(the status column has value `notReady'). |
NOTE WELL |
This textual convention may be used for a MIB +
table, irrespective of whether the values of +
that table's conceptual rows are able to be +
modified while it is active, or whether its +
conceptual rows must be taken out of service +
in order to be modified. That is, it is the +
responsibility of the DESCRIPTION clause of +
the status column to specify whether the +
status column must be `notInService' in order +
for the value of some other column of the +
same conceptual row to be modified. +
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To summarize the effect of having a conceptual row +
with a status column having a SYNTAX clause value +
of RowStatus, consider the following state +
diagram: +
STATE +
+--------------+-----------+-------------+-------------+
| A | B | C | D +
| |status col.|status column| +
|status column | is | is |status column+
ACTION |does not exist| notReady | notInService| is active+
--------------+--------------+-----------+-------------+-------------+
set status |noError ->D|inconsist- |inconsistent-|inconsistent-+
column to | or | entValue| Value| Value+
createAndGo |inconsistent- | | | +
| Value| | | +
--------------+--------------+-----------+-------------+-------------+
set status |noError see 1|inconsist- |inconsistent-|inconsistent-+
column to | or | entValue| Value| Value+
createAndWait |wrongValue | | | +
--------------+--------------+-----------+-------------+-------------+
set status |inconsistent- |inconsist- |noError |noError +
column to | Value| entValue| | +
active | | | | +
| | or | | +
| | | | +
| |see 2 ->C| ->D| ->D+
--------------+--------------+-----------+-------------+-------------+
set status |inconsistent- |inconsist- |noError |noError ->C+
column to | Value| entValue| | or+
notInService | | | ->C|wrongValue+
--------------+--------------+-----------+-------------+-------------+
set status |noError |noError |noError |noError +
column to | | | | +
destroy | ->A| ->A| ->A| ->A+
--------------+--------------+-----------+-------------+-------------+
set any other |see 3 |noError |noError |noError +
column to some| | | | +
value | ->A| see 1| ->C| ->D+
--------------+--------------+-----------+-------------+-------------+
(1) goto B or C, depending on information |
available to the agent. |
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(2) if other variable bindings in the same PDU |
provide values for any missing but required |
columns, then noError is returned and state C is |
entered. |
(3) at the discretion of the agent, either noError |
or inconsistentValue may be returned. |
NOTE: other processing of the set request may |
prevent a noError response from being returned, |
e.g., wrongValue, noCreation, etc. |
Conceptual Row Creation |
There are four potential interactions when |
creating a conceptual row: selecting an instance- |
identifier which is not in use; creating the |
conceptual row; initializing any objects for which |
the agent does not supply a default; and, making |
the conceptual row available for use by the |
managed device. |
Interaction 1: Selecting an Instance-Identifier |
The algorithm used to select an instance- |
identifier varies for each conceptual row. In |
some cases, the instance-identifier is |
semantically significant, e.g., the destination |
address of a route, and a management station |
selects the instance-identifier according to the |
semantics. |
In other cases, the instance-identifier is used |
solely to distinguish conceptual rows, and a |
management station without specific knowledge of |
the conceptual row might examine the instances |
present in order to determine an unused instance- |
identifier. (This approach may be used, but it is |
often highly sub-optimal; however, it is also a |
questionable practice for a naive management |
station to attempt conceptual row creation.) |
Alternately, the MIB module which defines the |
conceptual row might provide one or more objects |
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which provide assistance in determining an unused |
instance-identifier. For example, if the |
conceptual row is indexed by an integer-value, |
then an object having an integer-valued SYNTAX |
clause might be defined for such a purpose, |
allowing a management station to issue a |
management protocol retrieval operation. In order |
to avoid unnecessary collisions between competing |
management stations, `adjacent' retrievals of this |
object should be different. |
Finally, the management station could select a |
pseudo-random number to use as the index. In the |
event that this index was already in use and an |
inconsistentValue was returned in response to the |
management protocol set operation, the management |
station should simply select a new pseudo-random |
number and retry the operation. |
A MIB designer should choose between the two |
latter algorithms based on the size of the table |
(and therefore the efficiency of each algorithm). |
For tables in which a large number of entries are |
expected, it is recommended that a MIB object be |
defined that returns an acceptable index for |
creation. For tables with small numbers of |
entries, it is recommended that the latter |
pseudo-random index mechanism be used. |
Interaction 2: Creating the Conceptual Row |
Once an unused instance-identifier has been |
selected, the management station determines if it |
wishes to create and activate the conceptual row |
in one transaction or in a negotiated set of |
interactions. |
Interaction 2a: Creating and Activating the |
Conceptual Row |
The management station must first determine the |
column requirements, i.e., it must determine those |
columns for which it must or must not provide |
values. Depending on the complexity of the table |
and the management station's knowledge of the |
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agent's capabilities, this determination can be |
made locally by the management station. |
Alternately, |
the management station issues a management
protocol get operation to examine all columns in |
the conceptual row that it wishes to create. In |
response, for each column, there are three |
possible outcomes: |
- a value is returned, indicating that some |
other management station has already created |
this conceptual row. We return to |
interaction 1. |
- the exception `noSuchInstance' is returned, |
indicating that the agent implements the |
object-type associated with this column, and |
that this column in at least one conceptual |
row would be accessible in the MIB view used |
by the retrieval were it to exist. For those |
columns to which the agent provides read- |
create access, the `noSuchInstance' exception |
tells the management station that it should |
supply a value for this column when the |
conceptual row is to be created. |
- the exception `noSuchObject' is returned, |
indicating that the agent does not implement |
the object-type associated with this column |
or that there is no conceptual row for which |
this column would be accessible in the MIB |
view used by the retrieval. As such, the |
management station can not issue any |
management protocol set operations to create |
an instance of this column. |
Once the column requirements have been determined, |
a management protocol set operation is accordingly |
issued. This operation also sets the new instance |
of the status column to `createAndGo'. |
When the agent processes the set operation, it |
verifies that it has sufficient information to |
make the conceptual row available for use by the |
managed device. The information available to the |
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agent is provided by two sources: the management |
protocol set operation which creates the |
conceptual row, |
and, implementation-specific defaults supplied by |
the agent (note that an agent must provide |
implementation-specific defaults for at least |
those objects which it implements as read-only). |
If there is sufficient information available, then |
the conceptual row is created, a `noError' |
response is returned, the status column is set to |
`active', and no further interactions are |
necessary (i.e., interactions 3 and 4 are |
skipped). If there is insufficient information, |
then the conceptual row is not created, and the |
set operation fails with an error of |
`inconsistentValue'. On this error, the |
management station can issue a management protocol |
retrieval operation to determine if this was |
because it failed to specify a value for a |
required column, or, because the selected instance |
of the status column already existed. In the |
latter case, we return to interaction 1. In the |
former case, the management station can re-issue |
the set operation with the additional information, |
or begin interaction 2 again using `createAndWait' |
in order to negotiate creation of the conceptual |
row. |
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NOTE WELL |
Regardless of the method used to determine |
the column requirements, it is possible that |
the management station might deem a column |
necessary when, in fact, the agent will not |
allow that particular columnar instance to be |
created or written. In this case, the |
management protocol set operation will fail |
with an error such as `noCreation' or |
`notWritable'. In this case, the management |
station decides whether it needs to be able |
to set a value for that particular columnar |
instance. If not, the management station |
re-issues the management protocol set |
operation, but without setting a value for |
that particular columnar instance; otherwise, |
the management station aborts the row |
creation algorithm. |
Interaction 2b: Negotiating the Creation of the |
Conceptual Row |
The management station issues a management |
protocol set operation which sets the desired |
instance of the status column to `createAndWait'. |
If the agent is unwilling to process a request of |
this sort, the set operation fails with an error |
of `wrongValue'. (As a consequence, such an agent |
must be prepared to accept a single management |
protocol set operation, i.e., interaction 2a |
above, containing all of the columns indicated by |
its column requirements.) Otherwise, the |
conceptual row is created, a `noError' response is |
returned, and the status column is immediately set |
to either `notInService' or `notReady', depending |
on whether it has sufficient information to make |
the conceptual row available for use by the |
managed device. If there is sufficient |
information available, then the status column is |
set to `notInService'; otherwise, if there is |
insufficient information, then the status column |
is set to `notReady'. Regardless, we proceed to |
interaction 3. |
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Interaction 3: Initializing non-defaulted Objects |
The management station must now determine the |
column requirements. It issues a management |
protocol get operation to examine all columns in |
the created conceptual row. In the response, for |
each column, there are three possible outcomes: |
- a value is returned, indicating that the |
agent implements the object-type associated |
with this column and had sufficient |
information to provide a value. For those |
columns to which the agent provides read- |
create access, a value return tells the |
management station that it may issue |
additional management protocol set |
operations, if it desires, in order to change |
the value associated with this column. |
- the exception `noSuchInstance' is returned, |
indicating that the agent implements the |
object-type associated with this column, and |
that this column in at least one conceptual |
row would be accessible in the MIB view used |
by the retrieval were it to exist. |
However, the agent does not have sufficient |
information to provide a value, and until a |
value is provided, the conceptual row may not |
be made available for use by the managed |
device. For those columns to which the agent |
provides read-create access, the |
`noSuchInstance' exception tells the |
management station that it must issue |
additional management protocol set |
operations, in order to provide a value |
associated with this column. |
- the exception `noSuchObject' is returned, |
indicating that the agent does not implement |
the object-type associated with this column |
or that there is no conceptual row for which |
this column would be accessible in the MIB |
view used by the retrieval. |
As such, the management station can not issue |
any management protocol set operations to |
Expires June 22, 1993 [Page 16]
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create an instance of this column. |
If the value associated with the status column is |
`notReady', then the management station must first |
deal with all `noSuchInstance' columns, if any. |
Having done so, the value of the status column |
becomes `notInService', and we proceed to |
interaction 4. |
Interaction 4: Making the Conceptual Row Available |
Once the management station is satisfied with the |
values associated with the columns of the |
conceptual row, it issues a management protocol |
set operation to set the status column to |
`active'. If the agent has sufficient information |
to make the conceptual row available for use by |
the managed device, the management protocol set |
operation succeeds (a `noError' response is |
returned). Otherwise, the management protocol set |
operation fails with an error of |
`inconsistentValue'. |
NOTE WELL |
A conceptual row having a status column with |
value `notInService' or `notReady' is |
unavailable to the managed device. As such, |
it is possible for the managed device to |
create its own instances during the time |
between the management protocol set operation |
which sets the status column to |
`createAndWait' and the management protocol |
set operation which sets the status column to |
`active'. In this case, when the management |
protocol set operation is issued to set the |
status column to `active', the values held in |
the agent supersede those used by the managed |
device. |
If the management station is prevented from |
setting the status column to `active' (e.g., due |
to management station or network failure) the |
conceptual row will be left in the `notInService' |
or `notReady' state, consuming resources |
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indefinitely. The agent must detect conceptual |
rows that have been in either state for an |
abnormally long period of time and remove them. |
This period of time should be long enough to allow |
for human response time |
(including `think time') between the creation of |
the conceptual row and the setting of the status |
to `active'. It is suggested that this period be |
approximately 5 minutes in length. |
Conceptual Row Suspension |
When a conceptual row is `active', the management +
station may issue a management protocol set +
operation which sets the instance of the status +
column to `notInService'. If the agent is +
unwilling to do so, the set operation fails with +
an error of `wrongValue'. Otherwise, the +
conceptual row is taken out of service, and a +
`noError' response is returned. It is the +
responsibility of the the DESCRIPTION clause of +
the status column to indicate under what +
circumstances the status column should be taken +
out of service (e.g., in order for the value of +
some other column of the same conceptual row to be +
modified). +
Conceptual Row Deletion +
For deletion of conceptual rows, a management |
protocol set operation is issued which sets the |
instance of the status column to `destroy'. This |
request may be made regardless of the current |
value of the status column (e.g., it is possible |
to delete conceptual rows which are either |
`notReady', `notInService' or `active'.) |
If the operation succeeds, then all instances |
associated with the conceptual row are immediately |
removed." |
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SYNTAX INTEGER {
-- the following two values are states: |
-- these values may be read or written |
active(1), |
notInService(2), |
-- the following value is a state: +
-- this value may be read, but not written +
notReady(3), +
-- the following three values are +
-- actions: these values may be written, +
-- but are never read +
createAndGo(4), +
createAndWait(5), +
destroy(6) +
} +
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TimeStamp ::= TEXTUAL-CONVENTION
STATUS current
DESCRIPTION
"The value of MIB-II's sysUpTime object at which a
specific occurrence happened. The specific
occurrence must be defined in the description of
any object defined using this type."
SYNTAX TimeTicks
TimeInterval ::= TEXTUAL-CONVENTION
STATUS current
DESCRIPTION
"A period of time, measured in units of 0.01
seconds."
SYNTAX INTEGER (0..2147483647)
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DateAndTime ::= TEXTUAL-CONVENTION
DISPLAY-HINT "2d-1d-1d,1d:1d:1d.1d,1a1d:1d"
STATUS current
DESCRIPTION
"A date-time specification.
field octets contents range
----- ------ -------- -----
1 1-2 year 0..65536
2 3 month 1..12
3 4 day 1..31
4 5 hour 0..23
5 6 minutes 0..59
6 7 seconds 0..60
(use 60 for leap-second)
7 8 deci-seconds 0..9
8 9 direction from UTC '+' / '-'
9 10 hours from UTC 0..11
10 11 minutes from UTC 0..59
For example, Tuesday May 26, 1992 at 1:30:15 PM
EDT would be displayed as:
1992-5-26,13:30:15.0,-4:0
Note that if only local time is known, then |
timezone information (fields 8-10) is not |
present." |
SYNTAX OCTET STRING (SIZE (8 | 11))
END
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3. Mapping of the TEXTUAL-CONVENTION macro
The TEXTUAL-CONVENTION macro is used to convey the syntax and
semantics associated with a textual convention. It should be
noted that the expansion of the TEXTUAL-CONVENTION macro is
something which conceptually happens during implementation and
not during run-time.
For all descriptors appearing in an information module, the
descriptor shall be unique and mnemonic, and shall not exceed
64 characters in length. Further, the hyphen is not allowed
as a character in the name of any textual convention.
3.1. Mapping of the DISPLAY-HINT clause
The DISPLAY-HINT clause, which need not be present, gives a
hint as to how the value of an instance of an object with the
syntax defined using this textual convention might be
displayed. The DISPLAY-HINT clause may only be present when
the syntax has an underlying primitive type of INTEGER or
OCTET STRING.
When the syntax has an underlying primitive type of INTEGER,
the hint consists of a single character suggesting a display
format, either: `x' for hexadecimal, `d' for decimal, or `o'
for octal, or `b' for binary.
When the syntax has an underlying primitive type of OCTET
STRING, the hint consists of one or more octet-format
specifications. Each specification consists of five parts,
with each part using and removing zero or more of the next
octets from the value and producing the next zero or more
characters to be displayed. The octets within the value are
processed in order of significance, most significant first.
The five parts of a octet-format specification are:
(1) the (optional) repeat indicator; if present, this part is
a `*', and indicates that the current octet of the value
is to be used as the repeat count. The repeat count is
an unsigned integer (which may be zero) which specifies
how many times the remainder of this octet-format
specification should be successively applied. If the
repeat indicator is not present, the repeat count is one.
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(2) the octet length: one or more decimal digits specifying
the number of octets of the value to be used and
formatted by this octet-specification. Note that the
octet length can be zero. If less than this number of
octets remain in the value, then the lesser number of
octets are used.
(3) the display format, either: `x' for hexadecimal, `d' for
decimal, `o' for octal, or `a' for ascii. If the octet
length part is greater than one, and the display format
part refers to a numeric format, then network-byte
ordering (big-endian encoding) is used interpreting the
octets in the value.
(4) the (optional) display separator character; if present,
this part is a single character which is produced for
display after each application of this octet-
specification; however, this character is not produced
for display if it would be immediately followed by the
display of the repeat terminator character for this
octet-specification. This character can be any character
other than a decimal digit and a `*'.
(5) the (optional) repeat terminator character, which can be
present only if the display separator character is
present and this octet-specification begins with a repeat
indicator; if present, this part is a single character
which is produced after all the zero or more repeated
applications (as given by the repeat count) of this
octet-specification. This character can be any character
other than a decimal digit and a `*'.
Output of a display separator character or a repeat terminator
character is suppressed if it would occur as the last
character of the display.
If the octets of the value are exhausted before all the
octet-format specification have been used, then the excess
specifications are ignored. If additional octets remain in
the value after interpreting all the octet-format
specifications, then the last octet-format specification is
re-interpreted to process the additional octets, until no
octets remain in the value.
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3.2. Mapping of the STATUS clause
The STATUS clause, which must be present, indicates whether
this definition is current or historic.
The values "current", and "obsolete" are self-explanatory.
The "deprecated" value indicates that the textual convention
is obsolete, but that an implementor may wish to support that
object to foster interoperability with older implementations.
3.3. Mapping of the DESCRIPTION clause
The DESCRIPTION clause, which must be present, contains a
textual definition of the textual convention, which provides
all semantic definitions necessary for implementation, and
should embody any information which would otherwise be
communicated in any ASN.1 commentary annotations associated
with the object.
Note that, in order to conform to the ASN.1 syntax, the entire
value of this clause must be enclosed in double quotation
marks, and therefore cannot itself contain double quotation
marks, although the value may be multi-line.
3.4. Mapping of the REFERENCE clause
The REFERENCE clause, which need not be present, contains a
textual cross-reference to a related item defined in some
other published work.
3.5. Mapping of the SYNTAX clause
The SYNTAX clause, which must be present, defines abstract
data structure corresponding to the textual convention. The
data structure must be one of the alternatives defined in the
ObjectSyntax CHOICE [2].
Full ASN.1 sub-typing is allowed, as appropriate to the
underingly ASN.1 type, primarily as an aid to implementors in
understanding the meaning of the textual convention. Of
course, sub-typing is not allowed for textual conventions
derived from either the Counter32 or Counter64 types, but is
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allowed for textual conventions derived from the Gauge32 type.
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4. Acknowledgements
PhysAddress (and textual conventions) originated in RFC 1213.
MacAddress originated in RFCs 1230 and 1231.
TruthValue originated in RFC 1253.
AutonomousType and InstancePointer originated in RFC 1316.
RowStatus originated in RFC 1271.
A special thanks to Bancroft Scott of Open Systems Solutions,
Inc., for helping in the definition of the TEXTUAL-CONVENTIONS
macro.
Finally, the comments of the SNMP version 2 working group are
gratefully acknowledged:
Beth Adams, Network Management Forum
Steve Alexander, INTERACTIVE Systems Corporation
David Arneson, Cabletron Systems
Toshiya Asaba,
Fred Baker, ACC
Jim Barnes, Xylogics, Inc.
Brian Bataille
Andy Bierman, SynOptics Communications, Inc.
Uri Blumenthal, IBM Corporation
Fred Bohle, Interlink
Jack Brown
Theodore Brunner, Bellcore
Stephen F. Bush, GE Information Services
Deirdre C. Kostik, Bellcore
Jeff Case, University of Tennessee, Knoxville
John Chang, IBM Corporation
Szusin Chen, Sun Microsystems
Robert Ching
Chris Chiotasso, Ungermann-Bass
Bobby A. Clay, NASA/Boeing
John Cooke, Chipcom
Tracy Cox, Bellcore
Juan Cruz, Datability, Inc.
David Cullerot, Cabletron Systems
Cathy Cunningham, Microcom
James R. (Chuck) Davin, Bellcore
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Michael Davis, Clearpoint
Mike Davison, FiberCom
Cynthia DellaTorre, MITRE
Taso N. Devetzis, Bellcore
Manual Diaz, DAVID Systems, Inc.
Jon Dreyer, Sun Microsystems
Susan E. Hicks, Martin Marietta Energy Systems
David Engel, Optical Data Systems
Mike Erlinger, Lexcel
Roger Fajman, NIH
Daniel Fauvarque, Sun Microsystems
Karen Frisa, CMU
Shari Galitzer, MITRE
Shawn Gallagher, Digital Equipment Corporation
Richard Graveman, Bellcore
Maria Greene, Xyplex, Inc.
Michel Guittet, Apple
Robert Gutierrez, NASA
Bill Hagerty, Cabletron Systems
Gary W. Haney, Martin Marietta Energy Systems
Patrick Hanil, Nokia Telecommunications
Matt Hecht, SNMP Research, Inc.
Edward A. Heiner, Jr., Synernetics Inc.
Geral Holzhauer, Apple
John Hopprich, DAVID Systems, Inc.
Jeff Hughes, Hewlett-Packard
Robin Iddon, Axon Networks, Inc.
David Itusak
Kevin M. Jackson, Concord Communications, Inc.
Ole J. Jacobsen, Interop Company
Ronald Jacoby, Silicon Graphics, Inc.
Satish Joshi, SynOptics Communications, Inc.
Frank Kastenholz, FTP Software
Mark Kepke, Hewlett-Packard
Ken Key, SNMP Research, Inc.
Zbiginew Kielczewski, Eicon
Jongyeoi Kim
Andrew Knutsen, The Santa Cruz Operation
Michael L Kornegay, VisiSoft
Cheryl Krupczak, Georgia Tech
Steven L. Waldbusser, Carnegie Mellon Universitty
Mark S. Lewis, Telebit
David Lin
David Lindemulder, AT&T/NCR
Ben Lisowski, Sprint
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David Liu, Bell-Northern Research
John Lunny, The Wollongong Group
Robert C. Lushbaugh Martin, Marietta Energy Systems
Michael Luufer, BBN
Carl Madison, Star-Tek, Inc.
Keith McCloghrie, Hughes LAN Systems
Evan McGinnis, 3Com Corporation
Bill McKenzie, IBM Corporation
Donna McMaster, SynOptics Communications, Inc.
John Medicke, IBM Corporation
Doug Miller, Telebit
Dave Minnich, FiberCom
Mohammad Mirhakkak, MITRE
Rohit Mital, Protools
George Mouradian, AT&T Bell Labs
Patrick Mullaney, Cabletron Systems
Dan Myers, 3Com Corporation
Rina Nathaniel, Rad Network Devices Ltd.
Hien V. Nguyen, Sprint
Mo Nikain
Tom Nisbet
William B. Norton, MERIT
Steve Onishi, Wellfleet Communications, Inc.
David T. Perkins, SynOptics Communications, Inc.
Carl Powell, BBN
Ilan Raab, SynOptics Communications, Inc.
RIchard Ramons, AT&T
Venkat D. Rangan, Metric Network Systems, Inc.
Louise Reingold, Sprint
Sam Roberts, Farallon Computing, Inc.
Kary Robertson, Concord Communications, Inc.
Dan Romascanu, Lannet Data Communications Ltd.
Marshall T. Rose, Dover Beach Consulting, Inc.
Shawn A. Routhier, Epilogue Technology Corporation
Chris Rozman
Asaf Rubissa, Fibronics
Jon Saperia, Digital Equipment Corporation
Michael Sapich
Mike Scanlon, Interlan
Sam Schaen, MITRE
John Seligson, Ultra Network Technologies
Paul A. Serice, Corporation for Open Systems
Chris Shaw, Banyan Systems
Timon Sloane
Robert Snyder, Cisco Systems
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Joo Young Song
Roy Spitier, Sprint
Einar Stefferud, Network Management Associates
John Stephens, Cayman Systems, Inc.
Bob Stewart, Xyplex, Inc. (chair)
Kaj Tesink, Bellcore
Dean Throop, Data General
Ahmet Tuncay, France Telecom-CNET
Maurice Turcotte, Racal Datacom
Warren Vik, INTERACTIVE Systems Corporation
Yannis Viniotis
Steve Waldbusser, CMU
Timothy M. Walden, ACC
Alice Wang, Sun Microsystems
James Watt, Newbridge
Luanne Waul, Timeplex
Donald E. Westlake III, Digital Equipment Corporation
Gerry White
Bert Wijnen, IBM Corporation
Peter Wilson, 3Com Corporation
Steven Wong, Digital Equipment Corporation
Randy Worzella, IBM Corporation
Daniel Woycke, MITRE
Honda Wu
Jeff Yarnell, Protools
Chris Young, Cabletron
Kiho Yum, 3Com Corporation
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5. References
[1] Information processing systems - Open Systems
Interconnection - Specification of Abstract Syntax
Notation One (ASN.1), International Organization for
Standardization. International Standard 8824, (December,
1987).
[2] J.D. Case, K. McCloghrie, M.T. Rose, S.L. Waldbusser,
Structure of Management Information for version 2 of the
Simple Network Management Protocol (SNMPv2). Internet-
Draft, (December 22, 1992). |
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Table of Contents
1 Introduction .......................................... 2
1.1 A Note on Terminology ............................... 3
2 Definitions ........................................... 4
3 Mapping of the TEXTUAL-CONVENTION macro ............... 22
3.1 Mapping of the DISPLAY-HINT clause .................. 22
3.2 Mapping of the STATUS clause ........................ 24
3.3 Mapping of the DESCRIPTION clause ................... 24
3.4 Mapping of the REFERENCE clause ..................... 24
3.5 Mapping of the SYNTAX clause ........................ 24
4 Acknowledgements ...................................... 26
5 References ............................................ 30
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