RFC4268
Network Working Group S. Chisholm Request for Comments: 4268 Nortel Networks Category: Standards Track D. Perkins
SNMPinfo
November 2005
Entity State MIB
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 (2005).
Abstract
This memo defines a portion of the Management Information Base (MIB) for use with network management protocols in the Internet community. In particular, it describes extensions to the Entity MIB to provide information about the state of physical entities.
In addition, this memo defines a set of Textual Conventions to represent various states of an entity. The intent is that these Textual Conventions will be imported and used in MIB modules that would otherwise define their own representations.
Contents
The Internet-Standard Management Framework
For a detailed overview of the documents that describe the current Internet-Standard Management Framework, please refer to section 7 of RFC 3410 RFC3410.
Managed objects are accessed via a virtual information store, termed the Management Information Base or MIB. MIB objects are generally accessed through the Simple Network Management Protocol (SNMP). Objects in the MIB are defined using the mechanisms defined in the Structure of Management Information (SMI). This memo specifies a MIB module that is compliant to the SMIv2, which is described in STD 58, RFC 2578 RFC2578, STD 58, RFC 2579 RFC2579 and STD 58, RFC 2580 RFC2580.
Entity State
The goal in adding state objects to the Entity MIB RFC4133 is to define a useful subset of the possible state attributes that could be tracked for a given entity and that both fit into the state models such as those used in the Interfaces MIB RFC2863 as well as leverage existing well-deployed models. The entStateTable contains state objects that are a subset of the popular ISO/OSI states that are also defined in ITU's X.731 specification [X.731]. Objects are defined to capture administrative, operational, and usage states. In addition, there are further state objects defined to provide more information for these three basic states.
Administrative state indicates permission to use or prohibition against using the entity and is imposed through the management services.
Operational state indicates whether or not the entity is physically installed and working. Note that unlike the ifOperStatus RFC2863, this operational state is independent of the administrative state.
Usage state indicates whether or not the entity is in use at a specific instance, and if so, whether or not it currently has spare capacity to serve additional users. In the context of this MIB, the usage state refers to the ability of an entity to service other entities within its containment hierarchy.
Alarm state indicates whether or not there are any alarms active against the entity. In addition to those alarm states defined in X.731 [X.731], warning and indeterminate status are also defined to provide a more complete mapping to the Alarm MIB RFC3877.
Standby state indicates whether the entity is currently running as hot standby or cold standby or is currently providing service.
The terms "state" and "status" are used interchangeably in this memo.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 RFC2119.
Hierarchical State Management
Physical entities exist within a containment hierarchy. Physical containment is defined by the entPhysicalContainedIn objectRFC4133. This raises some interesting issues not addressed in existing work on state management.
There are two types of state for an entity:
1) The state of the entity independent of the states of its parents and children in its containment hierarchy. This is often referred to as raw state.
2) The state of the entity, as it may be influenced by the state of its parents and children. This is often referred to as computed state.
All state objects in this memo are raw state.
Entity Redundancy
While this memo is not attempting to address the entire problem space around redundancy, the entStateStandby object provides an important piece of state information for entities, which helps identify which pieces of redundant equipment are currently providing service, and which are waiting in either hot or cold standby mode.
Physical Entity Users
There are three ways to define the 'user' of a physical entity
1. Direct containment in physical hierarchy
2. Anywhere in physical hierarchy
3. As defined by a means outside the scope of this MIB. This could include logical interfaces that could run on a port, software that could run on a module, etc.
Administrative, operational, alarm, and standby state use all three definitions of 'user'. Usage state supports only the concept of direct containment to simplify implementations of this object.
Physical Class Behavior
This MIB makes no effort to standardize the behaviors and characteristics of the various physical classes RFC4133, but rather how this information is reported. In looking at real-world products, items within the same physical class vary substantially. The MIB has therefore provided guidance on how to support objects where a particular instance of a physical class cannot support part or all of a particular state.
Relation to Other MIBs
Relation to the Interfaces MIB
The Interfaces MIB RFC2863 defines the ifAdminStatus object, which has states of up, down, and testing, and the ifOperStatus object, which has states of up, down, testing, unknown, dormant, notPresent, and lowerLayerDown.
An ifAdminStatus of 'up' is equivalent to setting the entStateAdmin object to 'unlocked'. An ifAdminStatus of 'down' is equivalent to setting the entStateAdmin object to either 'locked' or 'shuttingDown', depending on a system's interpretation of 'down'.
An ifOperStatus of 'up' is equivalent to an entStateOper value of 'enabled'. An ifOperStatus of 'down' due to operational failure is equivalent to an entStateOper value of 'disabled'. An ifOperStatus of 'down' due to being administratively disabled is equivalent to an entStateAdmin value of 'locked' and an entStateOper value of either 'enabled' or 'disabled' depending on whether there are any known issues that would prevent the entity from becoming operational when its entStateAdmin is set to 'unlocked'. An ifOperStatus of 'unknown' is equivalent to an entStateOper value of 'unknown'. The ifOperStatus values of 'testing' and 'dormant' are not explicitly supported by this MIB, but the state objects will be able to reflect other aspects of the entities' administrative and operational state. The ifOperStatus values of 'notPresent' and 'lowerLayerDown' are in some ways computed states and so are therefore not supported in this
MIB. They can, though, be computed by examining the states of entities within this object's containment hierarchy and other available related states.
Relation to Alarm MIB
The entStateAlarm object indicates whether or not there are any active alarms against this entity. If there are active alarms, then the alarmActiveTable in the Alarm MIB RFC3877 should be searched for rows whose alarmActiveResourceId matches this entPhysicalIndex.
Alternatively, if the alarmActiveTable is queried first and an active alarm with a value of alarmActiveResourceId that matches this entPhysicalIndex is found, then entStateAlarm can be used to quickly determine if there are additional active alarms with a different severity against this physical entity.
Relation to Bridge MIB
For entities of physical type of 'port' that support the dot1dStpPortEnable object in the Bridge MIB RFC4188, a value of 'enabled' is equivalent to setting the entStateAdmin object to 'unlocked'. Setting dot1dStpPortEnable to 'disabled' is equivalent to setting the entStateAdmin object to 'locked'.
Relation to the Host Resources MIB
The hrDeviceStatus object in the Host Resources MIB RFC2790 provides an operational state for devices. For entities that logically correspond to the concept of a device, a value of 'unknown' for hrDeviceStatus corresponds to an entStateOper value of 'unknown'. A value of 'running' corresponds to an entStateOper value of 'enabled'. A value of 'warning' also corresponds to an entStateOper value of 'enabled', but with appropriate bits set in the entStateAlarm object to indicate the alarms corresponding to the unusual error condition detected. A value of 'testing' or 'down' is equivalent to an entStateOper value of 'disabled'.
Textual Conventions
ENTITY-STATE-TC-MIB DEFINITIONS ::= BEGIN
IMPORTS
MODULE-IDENTITY, mib-2 FROM SNMPv2-SMI TEXTUAL-CONVENTION FROM SNMPv2-TC;
entityStateTc MODULE-IDENTITY
LAST-UPDATED "200511220000Z"
ORGANIZATION "IETF Entity MIB Working Group"
CONTACT-INFO
"General Discussion: [email protected]
To Subscribe:
http://www.ietf.org/mailman/listinfo/entmib
http://www.ietf.org/html.charters/entmib-charter.html
Sharon Chisholm
Nortel Networks
PO Box 3511 Station C
Ottawa, Ont. K1Y 4H7
Canada
[email protected]
David T. Perkins
548 Qualbrook Ct
San Jose, CA 95110
USA
Phone: 408 394-8702
[email protected]"
DESCRIPTION
"This MIB defines state textual conventions.
Copyright (C) The Internet Society 2005. This version
of this MIB module is part of RFC 4268; see the RFC
itself for full legal notices."
REVISION "200511220000Z"
DESCRIPTION
"Initial version, published as RFC 4268."
::= { mib-2 130 }
EntityAdminState ::= TEXTUAL-CONVENTION
STATUS current
DESCRIPTION
" Represents the various possible administrative states.
A value of 'locked' means the resource is administratively
prohibited from use. A value of 'shuttingDown' means that
usage is administratively limited to current instances of
use. A value of 'unlocked' means the resource is not
administratively prohibited from use. A value of
'unknown' means that this resource is unable to
report administrative state."
SYNTAX INTEGER
{
unknown (1),
locked (2),
shuttingDown (3),
unlocked (4)
}
EntityOperState ::= TEXTUAL-CONVENTION
STATUS current
DESCRIPTION
" Represents the possible values of operational states.
A value of 'disabled' means the resource is totally
inoperable. A value of 'enabled' means the resource
is partially or fully operable. A value of 'testing'
means the resource is currently being tested
and cannot therefore report whether it is operational
or not. A value of 'unknown' means that this
resource is unable to report operational state."
SYNTAX INTEGER
{
unknown (1),
disabled (2),
enabled (3),
testing (4)
}
EntityUsageState ::= TEXTUAL-CONVENTION
STATUS current
DESCRIPTION
" Represents the possible values of usage states.
A value of 'idle' means the resource is servicing no
users. A value of 'active' means the resource is
currently in use and it has sufficient spare capacity
to provide for additional users. A value of 'busy'
means the resource is currently in use, but it
currently has no spare capacity to provide for
additional users. A value of 'unknown' means
that this resource is unable to report usage state."
SYNTAX INTEGER
{
unknown (1),
idle (2),
active (3),
busy (4)
}
EntityAlarmStatus ::= TEXTUAL-CONVENTION
STATUS current
DESCRIPTION
" Represents the possible values of alarm status.
An Alarm RFC3877 is a persistent indication
of an error or warning condition.
When no bits of this attribute are set, then no active
alarms are known against this entity and it is not under
repair.
When the 'value of underRepair' is set, the resource is
currently being repaired, which, depending on the
implementation, may make the other values in this bit
string not meaningful.
When the value of 'critical' is set, one or more critical
alarms are active against the resource. When the value
of 'major' is set, one or more major alarms are active
against the resource. When the value of 'minor' is set,
one or more minor alarms are active against the resource.
When the value of 'warning' is set, one or more warning
alarms are active against the resource. When the value
of 'indeterminate' is set, one or more alarms of whose
perceived severity cannot be determined are active
against this resource.
A value of 'unknown' means that this resource is
unable to report alarm state."
SYNTAX BITS
{
unknown (0),
underRepair (1),
critical(2),
major(3),
minor(4),
-- The following are not defined in X.733
warning (5),
indeterminate (6)
}
EntityStandbyStatus ::= TEXTUAL-CONVENTION
STATUS current
DESCRIPTION
" Represents the possible values of standby status.
A value of 'hotStandby' means the resource is not
providing service, but it will be immediately able to
take over the role of the resource to be backed up,
without the need for initialization activity, and will
contain the same information as the resource to be
backed up. A value of 'coldStandy' means that the
resource is to back up another resource, but will not
be immediately able to take over the role of a resource
to be backed up, and will require some initialization
activity. A value of 'providingService' means the
resource is providing service. A value of
'unknown' means that this resource is unable to
report standby state."
SYNTAX INTEGER
{
unknown (1),
hotStandby (2),
coldStandby (3),
providingService (4)
}
END
Definitions
ENTITY-STATE-MIB DEFINITIONS ::= BEGIN
IMPORTS
MODULE-IDENTITY, OBJECT-TYPE, NOTIFICATION-TYPE, mib-2
FROM SNMPv2-SMI
DateAndTime
FROM SNMPv2-TC
MODULE-COMPLIANCE, OBJECT-GROUP, NOTIFICATION-GROUP
FROM SNMPv2-CONF
entPhysicalIndex
FROM ENTITY-MIB
EntityAdminState, EntityOperState, EntityUsageState,
EntityAlarmStatus, EntityStandbyStatus
FROM ENTITY-STATE-TC-MIB;
entityStateMIB MODULE-IDENTITY
LAST-UPDATED "200511220000Z"
ORGANIZATION "IETF Entity MIB Working Group"
CONTACT-INFO
" General Discussion: [email protected]
To Subscribe:
http://www.ietf.org/mailman/listinfo/entmib
http://www.ietf.org/html.charters/entmib-charter.html
Sharon Chisholm
Nortel Networks
PO Box 3511 Station C
Ottawa, Ont. K1Y 4H7
Canada
[email protected]
David T. Perkins
548 Qualbrook Ct
San Jose, CA 95110
USA
Phone: 408 394-8702
[email protected]
"
DESCRIPTION
"This MIB defines a state extension to the Entity MIB.
Copyright (C) The Internet Society 2005. This version
of this MIB module is part of RFC 4268; see the RFC
itself for full legal notices."
REVISION "200511220000Z"
DESCRIPTION
"Initial version, published as RFC 4268."
::= { mib-2 131 }
-- Entity State Objects
entStateObjects OBJECT IDENTIFIER ::= { entityStateMIB 1 }
entStateTable OBJECT-TYPE
SYNTAX SEQUENCE OF EntStateEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"A table of information about state/status of entities.
This is a sparse augment of the entPhysicalTable. Entries
appear in this table for values of
entPhysicalClass RFC4133 that in this implementation
are able to report any of the state or status stored in
this table.
"
::= { entStateObjects 1 }
entStateEntry OBJECT-TYPE
SYNTAX EntStateEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"State information about this physical entity."
INDEX { entPhysicalIndex }
::= { entStateTable 1 }
EntStateEntry ::= SEQUENCE {
entStateLastChanged DateAndTime,
entStateAdmin EntityAdminState,
entStateOper EntityOperState,
entStateUsage EntityUsageState,
entStateAlarm EntityAlarmStatus,
entStateStandby EntityStandbyStatus
}
entStateLastChanged OBJECT-TYPE
SYNTAX DateAndTime
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The value of this object is the date and
time when the value of any of entStateAdmin,
entStateOper, entStateUsage, entStateAlarm,
or entStateStandby changed for this entity.
If there has been no change since
the last re-initialization of the local system,
this object contains the date and time of
local system initialization. If there has been
no change since the entity was added to the
local system, this object contains the date and
time of the insertion."
::= { entStateEntry 1 }
entStateAdmin OBJECT-TYPE
SYNTAX EntityAdminState
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"The administrative state for this entity.
This object refers to an entities administrative
permission to service both other entities within
its containment hierarchy as well other users of
its services defined by means outside the scope
of this MIB.
Setting this object to 'notSupported' will result
in an 'inconsistentValue' error. For entities that
do not support administrative state, all set
operations will result in an 'inconsistentValue'
error.
Some physical entities exhibit only a subset of the
remaining administrative state values. Some entities
cannot be locked, and hence this object exhibits only
the 'unlocked' state. Other entities cannot be shutdown
gracefully, and hence this object does not exhibit the
'shuttingDown' state. A value of 'inconsistentValue'
will be returned if attempts are made to set this
object to values not supported by its administrative
model."
::= { entStateEntry 2 }
entStateOper OBJECT-TYPE
SYNTAX EntityOperState
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The operational state for this entity.
Note that unlike the state model used within the
Interfaces MIB RFC2863, this object does not follow
the administrative state. An administrative state of
down does not predict an operational state
of disabled.
A value of 'testing' means that entity currently being
tested and cannot therefore report whether it is
operational or not.
A value of 'disabled' means that an entity is totally
inoperable and unable to provide service both to entities
within its containment hierarchy, or to other receivers
of its service as defined in ways outside the scope of
this MIB.
A value of 'enabled' means that an entity is fully or
partially operable and able to provide service both to
entities within its containment hierarchy, or to other
receivers of its service as defined in ways outside the
scope of this MIB.
Note that some implementations may not be able to
accurately report entStateOper while the
entStateAdmin object has a value other than 'unlocked'.
In these cases, this object MUST have a value
of 'unknown'."
::= { entStateEntry 3 }
entStateUsage OBJECT-TYPE
SYNTAX EntityUsageState
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The usage state for this entity.
This object refers to an entity's ability to service more
physical entities in a containment hierarchy. A value
of 'idle' means this entity is able to contain other
entities but that no other entity is currently
contained within this entity.
A value of 'active' means that at least one entity is
contained within this entity, but that it could handle
more. A value of 'busy' means that the entity is unable
to handle any additional entities being contained in it.
Some entities will exhibit only a subset of the
usage state values. Entities that are unable to ever
service any entities within a containment hierarchy will
always have a usage state of 'busy'. Some entities will
only ever be able to support one entity within its
containment hierarchy and will therefore only exhibit
values of 'idle' and 'busy'."
::= { entStateEntry 4 }
entStateAlarm OBJECT-TYPE
SYNTAX EntityAlarmStatus
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The alarm status for this entity. It does not include
the alarms raised on child components within its
containment hierarchy.
A value of 'unknown' means that this entity is
unable to report alarm state. Note that this differs
from 'indeterminate', which means that alarm state
is supported and there are alarms against this entity,
but the severity of some of the alarms is not known.
If no bits are set, then this entity supports reporting
of alarms, but there are currently no active alarms
against this entity."
::= { entStateEntry 5 }
entStateStandby OBJECT-TYPE
SYNTAX EntityStandbyStatus
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The standby status for this entity.
Some entities will exhibit only a subset of the
remaining standby state values. If this entity
cannot operate in a standby role, the value of this
object will always be 'providingService'."
::= { entStateEntry 6 }
-- Notifications
entStateNotifications OBJECT IDENTIFIER ::= { entityStateMIB 0 }
entStateOperEnabled NOTIFICATION-TYPE
OBJECTS { entStateAdmin,
entStateAlarm
}
STATUS current
DESCRIPTION
"An entStateOperEnabled notification signifies that the
SNMP entity, acting in an agent role, has detected that
the entStateOper object for one of its entities has
transitioned into the 'enabled' state.
The entity this notification refers can be identified by
extracting the entPhysicalIndex from one of the
variable bindings. The entStateAdmin and entStateAlarm
varbinds may be examined to find out additional
information on the administrative state at the time of
the operation state change as well as to find out whether
there were any known alarms against the entity at that
time that may explain why the physical entity has become
operationally disabled."
::= { entStateNotifications 1 }
entStateOperDisabled NOTIFICATION-TYPE
OBJECTS { entStateAdmin,
entStateAlarm }
STATUS current
DESCRIPTION
"An entStateOperDisabled notification signifies that the
SNMP entity, acting in an agent role, has detected that
the entStateOper object for one of its entities has
transitioned into the 'disabled' state.
The entity this notification refers can be identified by
extracting the entPhysicalIndex from one of the
variable bindings. The entStateAdmin and entStateAlarm
varbinds may be examined to find out additional
information on the administrative state at the time of
the operation state change as well as to find out whether
there were any known alarms against the entity at that
time that may affect the physical entity's
ability to stay operationally enabled."
::= { entStateNotifications 2 }
-- Conformance and Compliance
entStateConformance OBJECT IDENTIFIER ::= { entityStateMIB 2 }
entStateCompliances OBJECT IDENTIFIER
::= { entStateConformance 1 }
entStateCompliance MODULE-COMPLIANCE
STATUS current
DESCRIPTION
"The compliance statement for systems supporting
the Entity State MIB."
MODULE -- this module
MANDATORY-GROUPS {
entStateGroup
}
GROUP entStateNotificationsGroup
DESCRIPTION
"This group is optional."
OBJECT entStateAdmin
MIN-ACCESS read-only
DESCRIPTION
"Write access is not required."
::= { entStateCompliances 1 }
entStateGroups OBJECT IDENTIFIER ::= { entStateConformance 2 }
entStateGroup OBJECT-GROUP
OBJECTS {
entStateLastChanged,
entStateAdmin,
entStateOper,
entStateUsage,
entStateAlarm,
entStateStandby
}
STATUS current
DESCRIPTION
"Standard Entity State group."
::= { entStateGroups 1}
entStateNotificationsGroup NOTIFICATION-GROUP
NOTIFICATIONS {
entStateOperEnabled,
entStateOperDisabled
}
STATUS current
DESCRIPTION
"Standard Entity State Notification group."
::= { entStateGroups 2}
END
Security Considerations
The ENTITY-STATE-TC-MIB defined in section 4 does not define any management objects. Instead, it defines a set of textual conventions that may be used by other MIB modules to define management objects. Meaningful security considerations can only be written in the MIB modules that define management objects. The ENTITY-STATE-TC-MIB has therefore no impact on the security of the Internet.
The ENTITY-STATE-MIB defined in section 5 defines one management object -- entStateAdmin -- that has a MAX-ACCESS clause of read- write. The object may be considered sensitive or vulnerable in some network environments. The support for SET operations in a non-secure environment without proper protection can have a negative effect on network operations.
Note that setting the entStateAdmin to 'locked' or 'shuttingDown' can cause disruption of services ranging from those running on a port to those on an entire device, depending on the type of entity. Access to this object should be properly protected.
Access to the objects defined in this MIB allows one to figure out what the active and standby resources in a network are. This information can be used to optimize attacks on networks so even read-only access to this MIB should be properly protected.
SNMP versions prior to SNMPv3 did not include adequate security. Even if the network itself is secure (for example by using IPsec), even then, there is no control as to who on the secure network is allowed to access and GET/SET (read/change/create/delete) the objects in this MIB module.
It is RECOMMENDED that implementers consider the security features as provided by the SNMPv3 framework (see RFC3410, section 8), including full support for the SNMPv3 cryptographic mechanisms (for authentication and privacy).
Further, deployment of SNMP versions prior to SNMPv3 is NOT RECOMMENDED. Instead, it is RECOMMENDED to deploy SNMPv3 and to enable cryptographic security. It is then a customer/operator responsibility to ensure that the SNMP entity giving access to an instance of this MIB module is properly configured to give access to the objects only to those principals (entities) that have legitimate rights to indeed GET or SET (change/create/delete) them.
Acknowledgements
This document is a product of the Entity MIB Working Group.
References
Normative References
RFC2119 Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
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.
RFC4133 Bierman, A. and K. McCloghrie, "Entity MIB (Version 3)",
RFC 4133, August 2005.
Informative References
RFC2790 Waldbusser, S. and P. Grillo, "Host Resources MIB", RFC
2790, March 2000.
RFC2863 McCloghrie, K. and F. Kastenholz, "The Interfaces Group
MIB using SMIv2", RFC 2863, June 2000.
RFC3410 Case, J., Mundy, R., Partain, D., and B. Stewart,
"Introduction and Applicability Statements for Internet-
Standard Management Framework", RFC 3410, December 2002.
RFC3877 Chisholm, S. and D. Romascanu, "Alarm Management
Information Base (MIB)", RFC 3877, September 2004.
RFC4188 Norseth, K. and E. Bell, "Definitions of Managed Objects
for Bridges", RFC 4188, September 2005.
[X.731] ITU Recommendation X.731, "Information Technology - Open
Systems Interconnection - System Management: State
Management Function", 1992.
Authors' Addresses
Sharon Chisholm Nortel Networks PO Box 3511, Station C Ottawa, Ontario, K1Y 4H7 Canada
EMail: [email protected]
David T. Perkins 548 Qualbrook Ct San Jose, CA 95110 USA
Phone: 408 394-8702 EMail: [email protected]
Full Copyright Statement
Copyright (C) The Internet Society (2005).
This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights.
This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM 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.
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