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Definitions of Managed Objects for Bridges with Rapid Spanning Tree Protocol.
D. Levi, D. Harrington. December 2005.

 
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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. Table of Contents 1. The Internet-Standard Management Framework ......................2 2. Overview ........................................................2 3. Relationship to IEEE 802.1t and 802.1w Amendments ...............2 4. Relation to the BRIDGE-MIB ......................................3 5. Definitions for RSTP-MIB ........................................3 6. Acknowledgements ...............................................10 7. IANA Considerations ............................................10 8. Security Considerations ........................................10 9. Normative References ...........................................11 10. Informative References ........................................12 Levi & Harrington Standards Track [Page 1]
RFC 4318 RSTP MIB December 2005 1. 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]. 2. 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. 3. 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 Levi & Harrington Standards Track [Page 2]
RFC 4318 RSTP MIB December 2005 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 4. 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. 5. Definitions for RSTP-MIB RSTP-MIB DEFINITIONS ::= BEGIN -- ------------------------------------------------------------- -- MIB for IEEE 802.1w Rapid Spanning Tree Protocol -- ------------------------------------------------------------- IMPORTS Levi & Harrington Standards Track [Page 3]
RFC 4318 RSTP MIB December 2005 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: Bridge-mib@ietf.org" 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 Levi & Harrington Standards Track [Page 4]
RFC 4318 RSTP MIB December 2005 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 } Levi & Harrington Standards Track [Page 5]
RFC 4318 RSTP MIB December 2005 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. Levi & Harrington Standards Track [Page 6]
RFC 4318 RSTP MIB December 2005 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 Levi & Harrington Standards Track [Page 7]
RFC 4318 RSTP MIB December 2005 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. Levi & Harrington Standards Track [Page 8]
RFC 4318 RSTP MIB December 2005 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 Levi & Harrington Standards Track [Page 9]
RFC 4318 RSTP MIB December 2005 DESCRIPTION "The compliance statement for device support of Rapid Spanning Tree Protocol (RSTP) bridging services." MODULE MANDATORY-GROUPS { rstpBridgeGroup, rstpPortGroup } ::= { rstpCompliances 1 } END 6. 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. 7. IANA Considerations The IANA has assigned the following OID: Descriptor OBJECT IDENTIFIER value ---------- ----------------------- rstpMIB { mib-2 134 } 8. 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. Levi & Harrington Standards Track [Page 10]
RFC 4318 RSTP MIB December 2005 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. 9. 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. Levi & Harrington Standards Track [Page 11]
RFC 4318 RSTP MIB December 2005 [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. Levi & Harrington Standards Track [Page 12]
RFC 4318 RSTP MIB December 2005 Authors' Addresses David Levi Nortel Networks 4655 Great America Parkway Santa Clara, CA 95054 USA Phone: +1 408 495 5138 EMail: dlevi@nortel.com David Harrington Effective Software 50 Harding Rd. Portsmouth, NH 03801 USA Phone: +1 603 436 8634 EMail: ietfdbh@comcast.net Les Bell Hemel Hempstead Herts. HP2 7YU UK EMail: elbell@ntlworld.com Vivian Ngai Salt lake City, UT USA EMail: vivian_ngai@acm.org Levi & Harrington Standards Track [Page 13]
RFC 4318 RSTP MIB December 2005 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. Intellectual Property The IETF takes no position regarding the validity or scope of any Intellectual Property Rights 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; nor does it represent that it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. Copies of IPR disclosures made to the IETF Secretariat 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 proprietary rights by implementers or users of this specification can be obtained from the IETF on-line IPR repository at http://www.ietf.org/ipr. The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf- ipr@ietf.org. Acknowledgement Funding for the RFC Editor function is currently provided by the Internet Society. Levi & Harrington Standards Track [Page 14]

   

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