RFC4318
Network Working Group D. Levi Request for Comments: 4318 Nortel Networks Category: Standards Track D. Harrington
Effective Software
December 2005
Definitions of Managed Objects for Bridges
with Rapid Spanning Tree Protocol
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 an SMIv2 MIB module for managing the Rapid Spanning Tree capability defined by the IEEE P802.1t and P802.1w amendments to IEEE Std 802.1D-1998 for bridging between Local Area Network (LAN) segments. The objects in this MIB are defined to apply both to transparent bridging and to bridges connected by subnetworks other than LAN segments.
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.
Overview
This memo defines an SMIv2 MIB module for managing the Rapid Spanning Tree (RSTP) capability defined by the IEEE P802.1t [802.1t] and P802.1w [802.1w] amendments to IEEE Std 802.1D-1998 [802.1D-1998] for bridging between Local Area Network (LAN) segments. The objects in this MIB are defined to apply both to transparent bridging and to bridges connected by subnetworks other than LAN segments.
Relationship to IEEE 802.1t and 802.1w Amendments
This document defines managed objects for the Rapid Spanning Tree Protocol defined by the IEEE P802.1t and IEEE P802.1w amendments to 802.1D-1998.
RSTP-MIB Name IEEE 802.1 Reference
dot1dStp
dot1dStpVersion (w) 17.16.1 ForceVersion dot1dStpTxHoldCount (w) 17.16.6 TxHoldCount dot1dStpExtPortTable dot1dStpPortProtocolMigration (w) 17.18.10 mcheck dot1dStpPortAdminEdgePort (t) 18.3.3 adminEdgePort dot1dStpPortOperEdgePort (t) 18.3.4 operEdgePort dot1dStpPortAdminPointToPoint (w) 6.4.3 adminPointToPointMAC dot1dStpPortOperPointToPoint (w) 6.4.3 operPointToPointMAC dot1dStpPortAdminPathCost (D) 8.5.5.3 Path Cost
There are concerns that there may be changes made in the 802.1D-2004 edition that would lead to non-backward-compatible SMI changes for 802.1t and 802.1w managed objects in the MIB modules. The Bridge MIB working group decided to 'freeze' the technical content of the MIB modules at a level that is compatible with the 802.1t and 802.1w
versions, and leave to the IEEE 802.1 working group any updates beyond this.
For informational purposes only, these are the references for the above objects in 802.1D-2004 [802.1D-2004].
RSTP-MIB Name IEEE 802.1D-2004 Reference
dot1dStp
dot1dStpVersion 17.13.4 ForceVersion dot1dStpTxHoldCount 17.13.12 TxHoldCount dot1dStpExtPortTable dot1dStpPortProtocolMigration 17.19.13 mcheck dot1dStpPortAdminEdgePort 17.13.1 adminEdgePort dot1dStpPortOperEdgePort 17.19.17 operEdgePort dot1dStpPortAdminPointToPoint 6.4.3 adminPointToPointMAC dot1dStpPortOperPointToPoint 6.4.3 operPointToPointMAC dot1dStpPortAdminPathCost 17.13.11 Path Cost
Relation to the BRIDGE-MIB
The objects in the RSTP-MIB supplement those defined in the Bridge MIB RFC4188.
The Original BRIDGE-MIB RFC1493 has been updated in an SMIv2- compliant version RFC4188. Conformance statements have been added and some description and reference clauses have been updated. The interpretations of some objects were changed to accommodate IEEE 802.1t and 802.1w amendments.
The object dot1dStpPortPathCost32 was added to support IEEE 802.1t, and the permissible values of dot1dStpPriority and dot1dStpPortPriority have been clarified for bridges supporting IEEE 802.1t or IEEE 802.1w. The interpretation of dot1dStpTimeSinceTopologyChange has been clarified for bridges supporting the RSTP.
See the updated BRIDGE-MIB RFC4188 for details.
Definitions for RSTP-MIB
RSTP-MIB DEFINITIONS ::= BEGIN
-- ------------------------------------------------------------- -- MIB for IEEE 802.1w Rapid Spanning Tree Protocol -- -------------------------------------------------------------
IMPORTS
MODULE-IDENTITY, OBJECT-TYPE, Integer32, mib-2
FROM SNMPv2-SMI
TruthValue
FROM SNMPv2-TC
MODULE-COMPLIANCE, OBJECT-GROUP
FROM SNMPv2-CONF
dot1dStp, dot1dStpPortEntry
FROM BRIDGE-MIB;
rstpMIB MODULE-IDENTITY
LAST-UPDATED "200512070000Z"
ORGANIZATION "IETF Bridge MIB Working Group"
CONTACT-INFO
"Email: [email protected]"
DESCRIPTION
"The Bridge MIB Extension module for managing devices
that support the Rapid Spanning Tree Protocol defined
by IEEE 802.1w.
Copyright (C) The Internet Society (2005). This version of
this MIB module is part of RFC 4318; See the RFC itself for
full legal notices."
REVISION "200512070000Z"
DESCRIPTION
"The initial version of this MIB module as published in
RFC 4318."
::= { mib-2 134 }
-- ---------------------------------------------------------- -- -- subtrees in the RSTP-MIB -- ---------------------------------------------------------- --
rstpNotifications OBJECT IDENTIFIER ::= { rstpMIB 0 } rstpObjects OBJECT IDENTIFIER ::= { rstpMIB 1 } rstpConformance OBJECT IDENTIFIER ::= { rstpMIB 2 }
-- ------------------------------------------------------------- -- Addition to the dot1dStp group -- -------------------------------------------------------------
dot1dStpVersion OBJECT-TYPE
SYNTAX INTEGER {
stpCompatible(0),
rstp(2)
}
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"The version of Spanning Tree Protocol the bridge is
currently running. The value 'stpCompatible(0)'
indicates the Spanning Tree Protocol specified in
IEEE 802.1D-1998 and 'rstp(2)' indicates the Rapid
Spanning Tree Protocol specified in IEEE 802.1w and
clause 17 of 802.1D-2004. The values are directly from
the IEEE standard. New values may be defined as future
versions of the protocol become available.
The value of this object MUST be retained across
reinitializations of the management system."
REFERENCE
"IEEE 802.1w clause 14.8.1, 17.12, 17.16.1"
DEFVAL { rstp }
::= { dot1dStp 16 }
dot1dStpTxHoldCount OBJECT-TYPE
SYNTAX Integer32 (1..10)
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"The value used by the Port Transmit state machine to limit
the maximum transmission rate.
The value of this object MUST be retained across
reinitializations of the management system."
REFERENCE
"IEEE 802.1w clause 17.16.6"
DEFVAL { 3 }
::= { dot1dStp 17 }
-- -- { dot1dStp 18 } was used to represent dot1dStpPathCostDefault -- in an earlier version of this MIB. It has since been -- obsoleted, and should not be used. --
dot1dStpExtPortTable OBJECT-TYPE
SYNTAX SEQUENCE OF Dot1dStpExtPortEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"A table that contains port-specific Rapid Spanning Tree
information."
::= { dot1dStp 19 }
dot1dStpExtPortEntry OBJECT-TYPE
SYNTAX Dot1dStpExtPortEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"A list of Rapid Spanning Tree information maintained by
each port."
AUGMENTS { dot1dStpPortEntry }
::= { dot1dStpExtPortTable 1 }
Dot1dStpExtPortEntry ::=
SEQUENCE {
dot1dStpPortProtocolMigration
TruthValue,
dot1dStpPortAdminEdgePort
TruthValue,
dot1dStpPortOperEdgePort
TruthValue,
dot1dStpPortAdminPointToPoint
INTEGER,
dot1dStpPortOperPointToPoint
TruthValue,
dot1dStpPortAdminPathCost
Integer32
}
dot1dStpPortProtocolMigration OBJECT-TYPE
SYNTAX TruthValue
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"When operating in RSTP (version 2) mode, writing true(1)
to this object forces this port to transmit RSTP BPDUs.
Any other operation on this object has no effect and
it always returns false(2) when read."
REFERENCE
"IEEE 802.1w clause 14.8.2.4, 17.18.10, 17.26"
::= { dot1dStpExtPortEntry 1 }
dot1dStpPortAdminEdgePort OBJECT-TYPE
SYNTAX TruthValue
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"The administrative value of the Edge Port parameter. A
value of true(1) indicates that this port should be
assumed as an edge-port, and a value of false(2) indicates
that this port should be assumed as a non-edge-port.
Setting this object will also cause the corresponding
instance of dot1dStpPortOperEdgePort to change to the
same value. Note that even when this object's value
is true, the value of the corresponding instance of
dot1dStpPortOperEdgePort can be false if a BPDU has
been received.
The value of this object MUST be retained across
reinitializations of the management system."
REFERENCE
"IEEE 802.1t clause 14.8.2, 18.3.3"
::= { dot1dStpExtPortEntry 2 }
dot1dStpPortOperEdgePort OBJECT-TYPE
SYNTAX TruthValue
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The operational value of the Edge Port parameter. The
object is initialized to the value of the corresponding
instance of dot1dStpPortAdminEdgePort. When the
corresponding instance of dot1dStpPortAdminEdgePort is
set, this object will be changed as well. This object
will also be changed to false on reception of a BPDU."
REFERENCE
"IEEE 802.1t clause 14.8.2, 18.3.4"
::= { dot1dStpExtPortEntry 3 }
dot1dStpPortAdminPointToPoint OBJECT-TYPE
SYNTAX INTEGER {
forceTrue(0),
forceFalse(1),
auto(2)
}
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"The administrative point-to-point status of the LAN segment
attached to this port, using the enumeration values of the
IEEE 802.1w clause. A value of forceTrue(0) indicates
that this port should always be treated as if it is
connected to a point-to-point link. A value of
forceFalse(1) indicates that this port should be treated as
having a shared media connection. A value of auto(2)
indicates that this port is considered to have a
point-to-point link if it is an Aggregator and all of its
members are aggregatable, or if the MAC entity
is configured for full duplex operation, either through
auto-negotiation or by management means. Manipulating this
object changes the underlying adminPortToPortMAC.
The value of this object MUST be retained across
reinitializations of the management system."
REFERENCE
"IEEE 802.1w clause 6.4.3, 6.5, 14.8.2"
::= { dot1dStpExtPortEntry 4 }
dot1dStpPortOperPointToPoint OBJECT-TYPE
SYNTAX TruthValue
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The operational point-to-point status of the LAN segment
attached to this port. It indicates whether a port is
considered to have a point-to-point connection.
If adminPointToPointMAC is set to auto(2), then the value
of operPointToPointMAC is determined in accordance with the
specific procedures defined for the MAC entity concerned,
as defined in IEEE 802.1w, clause 6.5. The value is
determined dynamically; that is, it is re-evaluated whenever
the value of adminPointToPointMAC changes, and whenever
the specific procedures defined for the MAC entity evaluate
a change in its point-to-point status."
REFERENCE
"IEEE 802.1w clause 6.4.3, 6.5, 14.8.2"
::= { dot1dStpExtPortEntry 5 }
dot1dStpPortAdminPathCost OBJECT-TYPE
SYNTAX Integer32 (0..200000000)
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"The administratively assigned value for the contribution
of this port to the path cost of paths toward the spanning
tree root.
Writing a value of '0' assigns the automatically calculated
default Path Cost value to the port. If the default Path
Cost is being used, this object returns '0' when read.
This complements the object dot1dStpPortPathCost or
dot1dStpPortPathCost32, which returns the operational value
of the path cost.
The value of this object MUST be retained across
reinitializations of the management system."
REFERENCE
"IEEE 802.1D-1998: Section 8.5.5.3"
::= { dot1dStpExtPortEntry 6 }
-- ------------------------------------------------------------- -- rstpMIB - Conformance Information -- -------------------------------------------------------------
rstpGroups OBJECT IDENTIFIER ::= { rstpConformance 1 }
rstpCompliances OBJECT IDENTIFIER ::= { rstpConformance 2 }
-- ------------------------------------------------------------- -- Units of conformance -- -------------------------------------------------------------
rstpBridgeGroup OBJECT-GROUP
OBJECTS {
dot1dStpVersion,
dot1dStpTxHoldCount
}
STATUS current
DESCRIPTION
"Rapid Spanning Tree information for the bridge."
::= { rstpGroups 1 }
rstpPortGroup OBJECT-GROUP
OBJECTS {
dot1dStpPortProtocolMigration,
dot1dStpPortAdminEdgePort,
dot1dStpPortOperEdgePort,
dot1dStpPortAdminPointToPoint,
dot1dStpPortOperPointToPoint,
dot1dStpPortAdminPathCost
}
STATUS current
DESCRIPTION
"Rapid Spanning Tree information for individual ports."
::= { rstpGroups 2 }
-- ------------------------------------------------------------- -- Compliance statements -- -------------------------------------------------------------
rstpCompliance MODULE-COMPLIANCE
STATUS current
DESCRIPTION
"The compliance statement for device support of Rapid
Spanning Tree Protocol (RSTP) bridging services."
MODULE
MANDATORY-GROUPS {
rstpBridgeGroup,
rstpPortGroup
}
::= { rstpCompliances 1 }
END
Acknowledgements
This document was produced on behalf of the Bridge MIB Working Group in the Operations and Management area of the Internet Engineering Task Force.
The authors wish to thank the members of the Bridge MIB Working Group, especially Alex Ruzin, for their comments and suggestions that improved this effort.
Vivian Ngai and Les Bell were the initial authors of this document, and did the bulk of the development work for this document.
IANA Considerations
The IANA has assigned the following OID:
Descriptor OBJECT IDENTIFIER value
---------- -----------------------
rstpMIB { mib-2 134 }
Security Considerations
There are a number of management objects defined in this MIB module with a MAX-ACCESS clause of read-write and/or read-create. Such objects 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. These are the tables and objects and their sensitivity/vulnerability:
Writable objects that could be misused to cause network delays and spanning tree instabilities include dot1dStpVersion, dot1dStpTxHoldCount, dot1dStpPortProtocolMigration, dot1dStpPortAdminEdgePort, and dot1dStpPortAdminPathCost.
Some of the readable objects in this MIB module (i.e., objects with a MAX-ACCESS other than not-accessible) may be considered sensitive or vulnerable in some network environments. It is thus important to control even GET and/or NOTIFY access to these objects and possibly to even encrypt the values of these objects when sending them over the network via SNMP. These are the tables and objects and their sensitivity/vulnerability:
dot1dStpVersion could be read by an attacker to identify environments containing applications or protocols that are potentially sensitive to RSTP mode.
dot1dStpPortAdminPointToPoint could be used to mislead an access control protocol, such as 802.1x, to believe that only one other system is attached to a LAN segment and to enable network access based on that assumption. This situation could permit potential man-in-the-middle attacks.
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 (users) that have legitimate rights to indeed GET or SET (change/create/delete) them.
Normative References
RFC2578 McCloghrie, K., Perkins, D., and J. Schoenwaelder,
"Structure of Management Information Version 2
(SMIv2)", STD 58, RFC 2578, April 1999.
RFC2579 McCloghrie, K., Perkins, D., and J. Schoenwaelder,
"Textual Conventions for SMIv2", STD 58, RFC 2579, April 1999.
RFC2580 McCloghrie, K., Perkins, D., and J. Schoenwaelder,
"Conformance Statements for SMIv2", STD 58, RFC 2580, April 1999.
[802.1D-1998] "Information technology - Telecommunications and
information exchange between systems - Local and
metropolitan area networks - Common specifications -
Part 3: Media Access Control (MAC) Bridges: Revision.
This is a revision of ISO/IEC 10038: 1993, 802.1j-1992
and 802.6k-1992. It incorporates P802.11c, P802.1p and
P802.12e." ISO/IEC 15802-3: 1998.
RFC4188 Norseth, K. and E. Bell, "Definitions of Managed
Objects for Bridges", RFC 4188, September 2005.
[802.1t] IEEE 802.1t-2001, "(Amendment to IEEE Standard 802.1D)
IEEE Standard for Information technology -
Telecommunications and information exchange between
systems - Local and metropolitan area networks - Common
specifications - Part 3: Media Access Control (MAC)
Bridges: Technical and Editorial Corrections".
[802.1w] IEEE 802.1w-2001, "(Amendment to IEEE Standard 802.1D)
IEEE Standard for Information technology--
Telecommunications and information exchange between
systems--Local and metropolitan area networks--Common
Specifications--Part 3: Media Access Control (MAC)
Bridges: Rapid Reconfiguation".
10. Informative References
RFC3410 Case, J., Mundy, R., Partain, D., and B. Stewart,
"Introduction and Applicability Statements for
Internet-Standard Management Framework", RFC 3410,
December 2002.
[802.1D-2004] IEEE Project 802 Local and Metropolitan Area Networks,
"IEEE Standard 802.1D-2004 MAC Bridges", 2004.
RFC1493 Decker, E., Langille, P., Rijsinghani, A., and K.
McCloghrie, "Definitions of Managed Objects for
Bridges", RFC 1493, July 1993.
Authors' Addresses
David Levi Nortel Networks 4655 Great America Parkway Santa Clara, CA 95054 USA
Phone: +1 408 495 5138 EMail: [email protected]
David Harrington Effective Software 50 Harding Rd. Portsmouth, NH 03801 USA
Phone: +1 603 436 8634 EMail: [email protected]
Les Bell Hemel Hempstead Herts. HP2 7YU UK
EMail: [email protected]
Vivian Ngai Salt lake City, UT USA
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.
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