📄 rfc3291.txt
字号:
Network Working Group M. Daniele
Request for Comments: 3291 Consultant
Obsoletes: 2851 B. Haberman
Category: Standards Track Consultant
S. Routhier
Wind River Systems, Inc.
J. Schoenwaelder
TU Braunschweig
May 2002
Textual Conventions for Internet Network Addresses
Status of this Memo
This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
Copyright Notice
Copyright (C) The Internet Society (2002). All Rights Reserved.
Abstract
This MIB module defines textual conventions to represent commonly
used Internet network layer addressing information. The intent is
that these textual conventions (TCs) will be imported and used in MIB
modules that would otherwise define their own representations.
This document obsoletes RFC 2851.
Daniele, et. al. Standards Track [Page 1]
RFC 3291 TCs for Internet Network Addresses May 2002
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 2
2. The SNMP Management Framework . . . . . . . . . . . . . . . . 4
3. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . 5
4. Usage Hints . . . . . . . . . . . . . . . . . . . . . . . . . 11
4.1 Table Indexing . . . . . . . . . . . . . . . . . . . . . . . . 12
4.2 Uniqueness of Addresses . . . . . . . . . . . . . . . . . . . 12
4.3 Multiple Addresses per Host . . . . . . . . . . . . . . . . . 13
4.4 Resolving DNS Names . . . . . . . . . . . . . . . . . . . . . 13
5. Table Indexing Example . . . . . . . . . . . . . . . . . . . . 13
6. Security Considerations . . . . . . . . . . . . . . . . . . . 16
7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 16
8. Intellectual Property Notice . . . . . . . . . . . . . . . . . 16
9. Changes from RFC 2851 . . . . . . . . . . . . . . . . . . . . 16
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 19
Full Copyright Statement . . . . . . . . . . . . . . . . . . . . . 20
1. Introduction
Several standards-track MIB modules use the IpAddress SMIv2 base
type. This limits the applicability of these MIB modules to IP
Version 4 (IPv4) since the IpAddress SMIv2 base type can only contain
4 byte IPv4 addresses. The IpAddress SMIv2 base type has become
problematic with the introduction of IP Version 6 (IPv6) addresses
[19].
This document defines multiple textual conventions as a mechanism to
express generic Internet network layer addresses within MIB module
specifications. The solution is compatible with SMIv2 (STD 58) and
SMIv1 (STD 16). New MIB definitions which need to express network
layer Internet addresses SHOULD use the textual conventions defined
in this memo. New MIB modules SHOULD NOT use the SMIv2 IpAddress
base type anymore.
A generic Internet address consists of two objects, one whose syntax
is InetAddressType, and another whose syntax is InetAddress. The
value of the first object determines how the value of the second
object is encoded. The InetAddress textual convention represents an
opaque Internet address value. The InetAddressType enumeration is
used to "cast" the InetAddress value into a concrete textual
convention for the address type. This usage of multiple textual
conventions allows expression of the display characteristics of each
address type and makes the set of defined Internet address types
extensible.
Daniele, et. al. Standards Track [Page 2]
RFC 3291 TCs for Internet Network Addresses May 2002
The textual conventions defined in this document can also be used to
represent generic Internet subnets and Internet address ranges. A
generic Internet subnet is represented by three objects, one whose
syntax is InetAddressType, a second one whose syntax is InetAddress
and a third one whose syntax is InetAddressPrefixLength. The
InetAddressType value again determines the concrete format of the
InetAddress value while the InetAddressPrefixLength identifies the
Internet network address prefix.
A generic range of consecutive Internet addresses is represented by
three objects. The first one has the syntax InetAddressType while
the remaining objects have the syntax InetAddress and specify the
start and end of the address range. The InetAddressType value again
determines the format of the InetAddress values.
The textual conventions defined in this document can be used to
define Internet addresses by using DNS domain names in addition to
IPv4 and IPv6 addresses. A MIB designer can write compliance
statements to express that only a subset of the possible address
types must be supported by a compliant implementation.
MIB developers who need to represent Internet addresses SHOULD use
these definitions whenever applicable, as opposed to defining their
own constructs. Even MIB modules that only need to represent IPv4 or
IPv6 addresses SHOULD use the InetAddressType/InetAddress textual
conventions defined in this memo.
There are many widely deployed MIB modules that use IPv4 addresses
and which need to be revised to support IPv6. These MIBs can be
categorized as follows:
1. MIB modules which define management information that is in
principle IP version neutral, but the MIB currently uses
addressing constructs specific to a certain IP version.
2. MIB modules which define management information that is specific
to particular IP version (either IPv4 or IPv6) and which is very
unlikely to ever be applicable to another IP version.
MIB modules of the first type SHOULD provide object definitions
(e.g., tables) that work with all versions of IP. In particular,
when revising a MIB module which contains IPv4 specific tables, it is
suggested to define new tables using the textual conventions defined
in this memo which support all versions of IP. The status of the new
tables SHOULD be "current" while the status of the old IP version
specific tables SHOULD be changed to "deprecated". The other
approach of having multiple similar tables for different IP versions
is strongly discouraged.
Daniele, et. al. Standards Track [Page 3]
RFC 3291 TCs for Internet Network Addresses May 2002
MIB modules of the second type, which are inherently IP version
specific, do not need to be redefined. Note that even in this case,
any additions to these MIB modules or new IP version specific MIB
modules SHOULD use the textual conventions defined in this memo.
MIB developers SHOULD NOT use the textual conventions defined in this
document to represent generic transport layer addresses. Instead the
SMIv2 TAddress textual convention and associated definitions should
be used for transport layer addresses.
The key words "MUST", "MUST NOT", "SHOULD", "SHOULD NOT" and "MAY" in
this document are to be interpreted as described in RFC 2119 [1].
2. The SNMP Management Framework
The SNMP Management Framework presently consists of five major
components:
o An overall architecture, described in RFC 2571 [2].
o Mechanisms for describing and naming objects and events for the
purpose of management. The first version of this Structure of
Management Information (SMI) is called SMIv1 and described in STD
16, RFC 1155 [3], STD 16, RFC 1212 [4] and RFC 1215 [5]. The
second version, called SMIv2, is described in STD 58, RFC 2578
[6], STD 58, RFC 2579 [7] and STD 58, RFC 2580 [8].
o Message protocols for transferring management information. The
first version of the SNMP message protocol is called SNMPv1 and
described in STD 15, RFC 1157 [9]. A second version of the SNMP
message protocol, which is not an Internet standards track
protocol, is called SNMPv2c and described in RFC 1901 [10] and RFC
1906 [11]. The third version of the message protocol is called
SNMPv3 and described in RFC 1906 [11], RFC 2572 [12] and RFC 2574
[13].
o Protocol operations for accessing management information. The
first set of protocol operations and associated PDU formats is
described in STD 15, RFC 1157 [9]. A second set of protocol
operations and associated PDU formats is described in RFC 1905
[14].
o A set of fundamental applications described in RFC 2573 [15] and
the view-based access control mechanism described in RFC 2575
[16].
A more detailed introduction to the current SNMP Management Framework
can be found in RFC 2570 [17].
Daniele, et. al. Standards Track [Page 4]
RFC 3291 TCs for Internet Network Addresses May 2002
Managed objects are accessed via a virtual information store, termed
the Management Information Base or MIB. Objects in the MIB are
defined using the mechanisms defined in the SMI.
This memo specifies a MIB module that is compliant to the SMIv2. A
MIB conforming to the SMIv1 can be produced through the appropriate
translations. The resulting translated MIB must be semantically
equivalent, except where objects or events are omitted because no
translation is possible (use of Counter64). Some machine readable
information in SMIv2 will be converted into textual descriptions in
SMIv1 during the translation process. However, this loss of machine
readable information is not considered to change the semantics of the
MIB.
3. Definitions
INET-ADDRESS-MIB DEFINITIONS ::= BEGIN
IMPORTS
MODULE-IDENTITY, mib-2, Unsigned32 FROM SNMPv2-SMI
TEXTUAL-CONVENTION FROM SNMPv2-TC;
inetAddressMIB MODULE-IDENTITY
LAST-UPDATED "200205090000Z"
ORGANIZATION
"IETF Operations and Management Area"
CONTACT-INFO
"Juergen Schoenwaelder (Editor)
TU Braunschweig
Bueltenweg 74/75
38106 Braunschweig, Germany
Phone: +49 531 391-3289
EMail: schoenw@ibr.cs.tu-bs.de
Send comments to <mibs@ops.ietf.org>."
DESCRIPTION
"This MIB module defines textual conventions for
representing Internet addresses. An Internet
address can be an IPv4 address, an IPv6 address
or a DNS domain name. This module also defines
textual conventions for Internet port numbers,
autonomous system numbers and the length of an
Internet address prefix."
REVISION "200205090000Z"
DESCRIPTION
"Second version, published as RFC 3291. This
revisions contains several clarifications and it
Daniele, et. al. Standards Track [Page 5]
RFC 3291 TCs for Internet Network Addresses May 2002
introduces several new textual conventions:
InetAddressPrefixLength, InetPortNumber,
InetAutonomousSystemNumber, InetAddressIPv4z,
and InetAddressIPv6z."
REVISION "200006080000Z"
DESCRIPTION
"Initial version, published as RFC 2851."
::= { mib-2 76 }
InetAddressType ::= TEXTUAL-CONVENTION
STATUS current
DESCRIPTION
"A value that represents a type of Internet address.
unknown(0) An unknown address type. This value MUST
be used if the value of the corresponding
InetAddress object is a zero-length string.
It may also be used to indicate an IP address
which is not in one of the formats defined
below.
ipv4(1) An IPv4 address as defined by the
InetAddressIPv4 textual convention.
ipv6(2) A global IPv6 address as defined by the
InetAddressIPv6 textual convention.
ipv4z(3) A non-global IPv4 address including a zone
index as defined by the InetAddressIPv4z
textual convention.
ipv6z(4) A non-global IPv6 address including a zone
index as defined by the InetAddressIPv6z
textual convention.
dns(16) A DNS domain name as defined by the
InetAddressDNS textual convention.
Each definition of a concrete InetAddressType value must be
accompanied by a definition of a textual convention for use
with that InetAddressType.
To support future extensions, the InetAddressType textual
convention SHOULD NOT be sub-typed in object type definitions.
It MAY be sub-typed in compliance statements in order to
require only a subset of these address types for a compliant
implementation.
Implementations must ensure that InetAddressType objects
Daniele, et. al. Standards Track [Page 6]
RFC 3291 TCs for Internet Network Addresses May 2002
and any dependent objects (e.g. InetAddress objects) are
consistent. An inconsistentValue error must be generated
if an attempt to change an InetAddressType object would,
for example, lead to an undefined InetAddress value. In
particular, InetAddressType/InetAddress pairs must be
changed together if the address type changes (e.g. from
ipv6(2) to ipv4(1))."
SYNTAX INTEGER {
unknown(0),
ipv4(1),
ipv6(2),
ipv4z(3),
ipv6z(4),
dns(16)
}
InetAddress ::= TEXTUAL-CONVENTION
STATUS current
DESCRIPTION
"Denotes a generic Internet address.
An InetAddress value is always interpreted within the context
of an InetAddressType value. Every usage of the InetAddress
textual convention is required to specify the InetAddressType
object which provides the context. It is suggested that the
InetAddressType object is logically registered before the
object(s) which use the InetAddress textual convention if
they appear in the same logical row.
The value of an InetAddress object must always be
consistent with the value of the associated InetAddressType
object. Attempts to set an InetAddress object to a value
which is inconsistent with the associated InetAddressType
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