Internet-Draft Endpoint MIB October 1999
Expires April, 2000
Internet Endpoint MIB
<draft-ops-endpoint-mib-01.txt>
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Copyright Notice
Copyright (C) The Internet Society (1999). All Rights Reserved.
Abstract
This MIB module defines constructs to represent commonly used
addressing information. The intent is that these definitions
will be imported and used in the various MIBs that would otherwise
define their own representations. This work is output from the
Operations and Management Area "IPv6MIB" design team.
1. The SNMP Management Framework
The SNMP Management Framework presently consists of five major
components:
o An overall architecture, described in RFC 2571 [RFC2571].
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 [RFC1155], STD 16, RFC 1212 [RFC1212] and RFC
1215 [RFC1215]. The second version, called SMIv2, is described
in STD 58, RFC 2578 [RFC2578], RFC 2579 [RFC2579] and RFC 2580
[RFC2580].
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 [RFC1157]. A second version of the
SNMP message protocol, which is not an Internet standards track
protocol, is called SNMPv2c and described in RFC 1901 [RFC1901]
and RFC 1906 [RFC1906]. The third version of the message
protocol is called SNMPv3 and described in RFC 1906 [RFC1906],
RFC 2572 [RFC2572] and RFC 2574 [RFC2574].
o Protocol operations for accessing management information. The
first set of protocol operations and associated PDU formats is
described in STD 15, RFC 1157 [RFC1157]. A second set of
protocol operations and associated PDU formats is described in
RFC 1905 [RFC1905].
o A set of fundamental applications described in RFC 2573
[RFC2573] and the view-based access control mechanism described
in RFC 2575 [RFC2575].
A more detailed introduction to the current SNMP Management Framework
can be found in RFC 2570 [RFC2570].
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.
2. Definitions
INET-ENDPOINT-MIB DEFINITIONS ::= BEGIN
IMPORTS
MODULE-IDENTITY FROM SNMPv2-SMI
TEXTUAL-CONVENTION FROM SNMPv2-TC;
inetEndpointMIB MODULE-IDENTITY
LAST-UPDATED "9910210000Z"
ORGANIZATION "IETF OPS Area"
CONTACT-INFO "Send comments to mibs@ops.ietf.org"
DESCRIPTION
"A MIB module for Internet address definitions."
::= { ??? }
--
--
-- New TCs for representing generic Internet endpoints.
-- These are roughly equivalent to TDomain and TAddress...
--
--
--
-- Internet endpoints types
--
InetEndpointType ::= TEXTUAL-CONVENTION
STATUS current
DESCRIPTION
"A value that represents a type of Internet endpoint.
Note that it is possible to sub-type objects defined with
this syntax by removing one or more enumerated values.
The DESCRIPTION clause of such objects (or their corresponding
InetEndpoint object) must document specific usage."
SYNTAX INTEGER {
other(0),
ipv4(1),
ipv6(2),
dns(3)
}
InetEndpoint ::= TEXTUAL-CONVENTION
STATUS current
DESCRIPTION
"Denotes an generic Internet endpoint.
A InetEndpoint value is always interpreted within the context of a
InetEndpointType value. Thus, each definition of a InetEndpointType
value must be accompanied by a definition of a textual convention
for use with that InetEndpointType.
When this Textual Convention is used as the syntax of an index object,
there may be issues with the limit of 128 sub-identifiers specified
in [SMIv2]. In this case, it is recommended that the OBJECT-TYPE
declaration include a 'SIZE' clause to limit the number of potential
instance sub-identifiers."
REFERENCE "See the TAddress TC in std58."
SYNTAX OCTET STRING (SIZE (0..255))
--
--
-- TCs for specific Internet endpoint values.
--
--
--
-- IPv4 Address
--
InetEndpointIPv4 ::= TEXTUAL-CONVENTION
DISPLAY-HINT "1d.1d.1d.1d"
STATUS current
DESCRIPTION
"Represents an IPv4 network address:
octets contents encoding
1-4 IP address network-byte order
The corresponding InetEndpointType is ipv4(1)."
SYNTAX OCTET STRING (SIZE (4))
--
-- IPv6 Address
--
InetEndpointIPv6 ::= TEXTUAL-CONVENTION
DISPLAY-HINT "2x:2x:2x:2x:2x:2x:2x:2x"
STATUS current
DESCRIPTION
"Represents an IPv6 network address:
octets contents encoding
1-16 IPv6 address network-byte order
The corresponding InetEndpointType is ipv6(2)."
REFERENCE "See the Ipv6Address TC in RFC 2465."
SYNTAX OCTET STRING (SIZE (16))
--
-- DNS Name
--
InetEndpointDNS ::= TEXTUAL-CONVENTION
DISPLAY-HINT "255a"
STATUS current
DESCRIPTION
"Represents a fully qualified DNS host name.
The corresponding InetEndpointType is dns(3).
The DESCRIPTION clause of InetEndpoint objects that
may have InetEndpointDNS values must fully describe
how (and when) such names are to be resolved to IP
addresses."
REFERENCE "RFCs 952 and 1123."
SYNTAX OCTET STRING (SIZE (1..255))
END
3. Usage
These definitions provide a mechanism to define generic
Internet-accessible endpoints within MIB specifications.
It is recommended that MIB developers use these definitions
when applicable, as opposed to defining their own constructs.
A generic Internet endpoint consists of two objects,
one whose syntax is InetEndpointType, and another whose
syntax is InetEndpoint. The value of the first object
determines how the value of the second object is encoded.
One particular usage of InetEndpointType/InetEndpoint pairs
is to avoid over-constraining an object definition by the
use of the IpAddress syntax. IpAddress limits an implementation
to using IPv4 addresses only, and as such SHOULD only be used
when the object truly is IPv4-specific.
4. Indexing
When a generic Internet endpoint is used as an index, both
the InetEndpointType and InetEndpoint objects MUST be used, and
the InetEndpointType object MUST come first in the INDEX clause.
The InetEndpointType object may be subtyped such that the resulting
index is of fixed length. But the more common usage will result
in variable-length indexes.
For variable length indexes, the IMPLIED keyword MUST NOT be used
in the INDEX clause. Instance subidentifiers are then of the form
T.N.O1.O2...On, where T is the value of the InetEndpointType object,
O1...On are the octets in the InetEndpoint object, and N is the
number of those octets.
There is a meaningful lexicographical ordering to tables indexed
in this fashion. Command generator applications may
o lookup specific endpoints of known type and value
o issue GetNext requests for endpoints of a single type
o issue GetNext requests for specific type and address prefix
It should be pointed out that another valid approach is to
define separate tables for different address types. For example,
one table might be indexed by an IpAddress object, and the other
table indexed by an Ipv6Address object. This is a decision for the
MIB designer. (For example, the tcpConnTable was left intact and a new
table added for TCP connections over IPv6, see RFC 2452.)
5. Uniqueness of Addresses
IPv4 addresses were intended to be globally unique, current
usage notwithstanding. IPv6 addresses were architected to
have different scopes and hence uniqueness. In particular,
IPv6 "link-local" and "site-local" addresses are not guaranteed
to be unique on any particular node. In such cases, the duplicate
addresses must be configured on different interfaces, so the combination
of IPv6 address/interface is unique.
For tables indexed by InetEndpointType/InetEndpoint pairs, where
there may be non-unique instances of InetEndpointIPv6, the recommended
approach is to add a third index object to ensure uniqueness.
It is recommended that the syntax of this third index object be
InterfaceIndexOrZero, imported from IF-MIB [RFC2233]. The value
of this object SHOULD be 0 when the value of the InetEndpointType
object is not ipv6(2).
6. Multiple InetEndpoints per Host
Note that a single host system may be configured with multiple
addresses (IPv4 or IPv6), and possibly with multiple DNS names.
Thus it is possible for a single host system to be represented
by multiple (unique) InetEndpointType/InetEndpoint pairs.
If this could be an implementation or usage issue the DESCRIPTION
clause of the relevant objects MUST fully describe required
behavior.
7. Resolving DNS Names
DNS names are translated to IP addresses when communication with
a host is required. This raises a temporal aspect to defining MIB
objects whose value is a DNS name; when is the name translated to
an address?
For example, consider an object defined to indicate a forwarding
destination, and whose value is a DNS name. When does the
forwarding entity resolve the DNS name? Each time forwarding occurs?
Once, when the object was instantiated?
The DESCRIPTION clause of such objects SHOULD precisely define
how (when) any required name to address resolution is done.
8. Usage Examples
Example 1:
fooTable OBJECT-TYPE
SYNTAX SEQUENCE OF FooEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"The foo table."
::= { bar 1 }
fooEntry OBJECT-TYPE
SYNTAX FooEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"A foo entry."
INDEX { fooPartnerType, fooPartner }
::= { fooTable 1 }
FooEntry ::= SEQUENCE {
fooPartnerType InetEndpointType,
fooPartner InetEndpoint,
fooStatus INTEGER,
fooDescr OCTET STRING
}
fooPartnerType ::= OBJECT-TYPE
SYNTAX InetEndpointType
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"The type of Internet endpoint by which the partner is reachable."
::= { fooEntry 1 }
fooPartner ::= OBJECT-TYPE
SYNTAX InetEndpoint (SIZE (0..64))
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"The Internet endpoint for the partner. Note that implementations
must limit themselves to a single entry in this table per reachable
partner. Also, if an Ipv6 endpoint is used, it must contain a globally
unique IPv6 address."
::= { fooEntry 2 }
Example 2:
sysAddrTable OBJECT-TYPE
SYNTAX SEQUENCE OF SysAddrEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"The sysAddr table."
::= { sysAddr 1 }
sysAddrEntry OBJECT-TYPE
SYNTAX SysAddrEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"A sysAddr entry."
INDEX { sysAddrType, sysAddr, sysAddrIfIndex }
::= { sysAddrTable 1 }
SysAddrEntry ::= SEQUENCE {
sysAddrPartnerType InetEndpointType,
sysAddrPartner InetEndpoint,
sysAddrIfIndex InterfaceIndexOrZero,
sysAddrStatus INTEGER,
sysAddrDescr OCTET STRING
}
sysAddrType ::= OBJECT-TYPE
SYNTAX InetEndpointType {
ipv4(1),
ipv6(2)
}
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"The type of system address."
::= { sysAddrEntry 1 }
sysAddr ::= OBJECT-TYPE
SYNTAX InetEndpoint (SIZE (4 | 16))
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"The system address."
::= { sysAddrEntry 2 }
sysAddrIfIndex ::= OBJECT-TYPE
SYNTAX InterfaceIndexOrZero
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"The system address interface. This object is used to disambiguate
duplicate system IPv6 addresses, and should be 0 for non-duplicate
addresses."
::= { sysAddrEntry 3 }
9. References
[RFC2233] K. McCloghrie, and F. Kastenholz, "The Interfaces Group MIB
using SMIv2", RFC 2233, November 1997
[RFC2571] Harrington, D., Presuhn, R., and B. Wijnen, "An Architecture
for Describing SNMP Management Frameworks", RFC 2571, April
1999
[RFC1155] Rose, M., and K. McCloghrie, "Structure and Identification
of Management Information for TCP/IP-based Internets", STD
16, RFC 1155, May 1990
[RFC1212] Rose, M., and K. McCloghrie, "Concise MIB Definitions", STD
16, RFC 1212, March 1991
[RFC1215] M. Rose, "A Convention for Defining Traps for use with the
SNMP", RFC 1215, March 1991
[RFC2578] McCloghrie, K., Perkins, D., Schoenwaelder, J., Case, J.,
Rose, M., and S. Waldbusser, "Structure of Management
Information Version 2 (SMIv2)", STD 58, RFC 2578, April 1999
[RFC2579] McCloghrie, K., Perkins, D., Schoenwaelder, J., Case, J.,
Rose, M., and S. Waldbusser, "Textual Conventions for
SMIv2", STD 58, RFC 2579, April 1999
[RFC2580] McCloghrie, K., Perkins, D., Schoenwaelder, J., Case, J.,
Rose, M., and S. Waldbusser, "Conformance Statements for
SMIv2", STD 58, RFC 2580, April 1999
[RFC1157] Case, J., Fedor, M., Schoffstall, M., and J. Davin, "Simple
Network Management Protocol", STD 15, RFC 1157, May 1990.
[RFC1901] Case, J., McCloghrie, K., Rose, M., and S. Waldbusser,
"Introduction to Community-based SNMPv2", RFC 1901, January
1996.
[RFC1906] Case, J., McCloghrie, K., Rose, M., and S. Waldbusser,
"Transport Mappings for Version 2 of the Simple Network
Management Protocol (SNMPv2)", RFC 1906, January 1996.
[RFC2572] Case, J., Harrington D., Presuhn R., and B. Wijnen, "Message
Processing and Dispatching for the Simple Network Management
Protocol (SNMP)", RFC 2572, April 1999
[RFC2574] Blumenthal, U., and B. Wijnen, "User-based Security Model
(USM) for version 3 of the Simple Network Management
Protocol (SNMPv3)", RFC 2574, April 1999
[RFC1905] Case, J., McCloghrie, K., Rose, M., and S. Waldbusser,
"Protocol Operations for Version 2 of the Simple Network
Management Protocol (SNMPv2)", RFC 1905, January 1996.
[RFC2573] Levi, D., Meyer, P., and B. Stewart, "SNMPv3 Applications",
RFC 2573, April 1999
[RFC2575] Wijnen, B., Presuhn, R., and K. McCloghrie, "View-based
Access Control Model (VACM) for the Simple Network
Management Protocol (SNMP)", RFC 2575, April 1999
[RFC2570] Case, J., Mundy, R., Partain, D., and B. Stewart,
"Introduction to Version 3 of the Internet-standard Network
Management Framework", RFC 2570, April 1999
10. Authors
This work was done by the IETF Ops Area "IPv6MIB" Design Team.
Comments should be posted to mibs@ops.ietf.org.
11. Notices
The IETF takes no position regarding the validity or scope of any
intellectual property or other rights that might be claimed to
pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights
might or might not be available; neither does it represent that it
has made any effort to identify any such rights. Information on the
IETF's procedures with respect to rights in standards-track and
standards-related documentation can be found in BCP-11. Copies of
claims of rights made available for publication and any assurances of
licenses to be made available, or the result of an attempt made to
obtain a general license or permission for the use of such propritary
rights by implementors or users of this specification can be obtained
from the IETF Secretariat.
The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary
rights which may cover technology that may be required to practice
this standard. Please address the information to the IETF Executive
Director.
12. Full Copyright Statement
Copyright (C) The Internet Society (1999). All Rights Reserved.
This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it
or assist in its implementation may be prepared, copied, published
and distributed, in whole or in part, without restriction of any
kind, provided that the above copyright notice and this paragraph are
included on all such copies and derivative works. However, this
document itself may not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of
developing Internet standards in which case the procedures for
copyrights defined in the Internet Standards process must be
followed, or as required to translate it into languages other than
English.
The limited permissions granted above are perpetual and will not be
revoked by the Internet Society or its successors or assigns.
This document and the information contained herein is provided on an
"AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
13. Appendix A
This appendix lists the issues raised over common addressing
MIB constructs, and the reasoning for the decisions made in
this module.
1. Efficient table lookups
Some existing MIBs have tables of generic addresses, indexed
by a random integer. This makes it impossible to lookup
specific addresses, or issue meaningful GetNext operations.
2. Common addressing should be defined such that no SMI changes
are required.
For example, the use of the ASN.1 CHOICE would really be an SMI
change.
3. TCs and DISPLAY-HINTS
A single object that contains both address type and value
does not provide a way to express the display characteristics
of each type.
(Also, such a single object requires code changes to handle updates,
whereas the solution chosen requires only MIB updates.)
4. Document the possible non-uniqueness of IPv6 addresses, and the
impact on indexing tables.
5. TDomain/TAddress limited to transport services
It was unclear if network layer addresses were appropriate
for use in TAddress values, since std58 refers specifically to
"transport addresses".
This point is less important than std58's definition that
TAddress values always be defined in the context of TDomain
values. Since did not want to index by OIDs, we did not
use TDomain and hence cannot use TAddress.
6. Harness the use of IpAddress
Several standard-track MIBs have used IpAddress syntax
inadvertently, needlessly limiting implementations to IPv4.
The specification under development should address this.
7. DNS names in addition to addresses
It is useful to be able to specify a system via a DNS name,
so the common addressing mechanism should support them.
Expires April, 2000