Network Working Group M. Dodge Request for Comments: 4069 ECI Telecom Category: Standards Track B. Ray PESA Switching Systems May 2005
Definitions of Managed Object Extensions for Very High Speed Digital Subscriber Lines (VDSL) Using Single Carrier Modulation (SCM) Line Coding
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 document defines a portion of the Management Information Base (MIB) module for use with network management protocols in the Internet community. In particular, it describes objects used for managing the Line Code Specific parameters of Very High Speed Digital Subscriber Line (VDSL) interfaces using Single Carrier Modulation (SCM) Line Coding. It is an optional extension to the VDSL-LINE-MIB, RFC 3728, which handles line code independent objects.
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Table of Contents
1. The Internet-Standard Management Framework .............. .... 2 2. Overview ..................................................... 2 2.1. Relationship of this MIB Module to Other MIB Modules ... 3 2.2. Conventions Used in the MIB Module ..................... 3 2.3. Structure .......................... .................. 3 2.4. Persistence ............................................ 4 3. Conformance and Compliance ................................... 5 4. Definitions .................................................. 5 5. Acknowledgements ............................................. 14 6. Security Considerations ...................................... 14 7. IANA Considerations .......................................... 16 8. References ................................................... 16 8.1. Normative References ................................... 16 8.2. Informative References ................................. 17
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].
This document describes an SNMP MIB module for managing the Line Code Dependent, Physical Medium Dependent (PMD) Layer of SCM VDSL Lines. These definitions are based upon the specifications for VDSL as defined in T1E1, European Telecommunications Standards Institute (ETSI), and International Telecommunication Union (ITU) documentation [T1E1311, T1E1011, T1E1013, ETSI2701, ETSI2702, ITU9931, ITU9971]. Additionally the protocol-dependent (and line-code dependent) management framework for VDSL lines specified by the Digital Subscriber Line Forum (DSLF) has been taken into consideration [DSLFTR57] and [DSLFWT96].
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The MIB module is located in the MIB tree under MIB-2 transmission.
The key words "MUST", "MUST NOT", "RECOMMENDED", and "SHOULD" in this document are to be interpreted as described in [RFC2119].
2.1. Relationship of this MIB Module to Other MIB Modules
The relationship of the VDSL Line MIB module to other MIB modules, in particular to the IF-MIB presented in RFC 2863 [RFC2863], is discussed in the VDSL-LINE-MIB, RFC 3728 [RFC3728]. This section outlines the relationship of this VDSL Line Extension MIB to the VDSL-LINE-MIB, RFC 3728 [RFC3728].
A. Vtuc -- VDSL transceiver unit at near (Central) end of line B. Vtur -- VDSL transceiver unit at Remote end of line C. Vtu -- One of either Vtuc or Vtur D. Curr -- Current F. Atn -- Attenuation J. LCS -- Line Code Specific K. Max -- Maximum Q. Mgn -- Margin S. PSD -- Power Spectral Density T. Rx -- Receive T. Snr -- Signal to Noise Ratio U. Tx -- Transmit
The SCM VDSL Line Extension MIB contains the following MIB group:
o vdslSCMGroup :
This group supports MIB objects for defining configuration profiles and for monitoring individual bands of Single Carrier Modulation (SCM) VDSL modems. It contains the following tables:
When the object vdslLineCoding is set to SCM, vdslLineConfProfileName is used as the index to vdslLineSCMConfProfileBandTable. The existence of an entry in any of the tables of the vdslSCMGroup is optional.
Note also that the interface indices in this MIB are maintained persistently. View-based Access Control Model (VACM) data relating to these SHOULD be stored persistently as well [RFC3415].
An SCM based VDSL agent does not have to implement this MIB to be compliant with RFC 3728 [RFC3728]. If the SCM VDSL Line Extension MIB is implemented then the following group is mandatory:
MODULE-IDENTITY, OBJECT-TYPE, Integer32, transmission, Unsigned32 FROM SNMPv2-SMI -- [RFC2578] TEXTUAL-CONVENTION, TruthValue, RowStatus FROM SNMPv2-TC -- [RFC2579] MODULE-COMPLIANCE, OBJECT-GROUP FROM SNMPv2-CONF -- [RFC2580] ifIndex FROM IF-MIB -- [RFC2863] vdslLineConfProfileName FROM VDSL-LINE-MIB; -- [RFC3728]
vdslExtSCMMIB MODULE-IDENTITY LAST-UPDATED "200504280000Z" -- April 28, 2005 ORGANIZATION "ADSLMIB Working Group" CONTACT-INFO "WG-email: adslmib@ietf.org Info: https://www1.ietf.org/mailman/listinfo/adslmib
Chair: Mike Sneed Sand Channel Systems Postal: P.O. Box 37324 Raleigh NC 27627-732 Email: sneedmike@hotmail.com Phone: +1 206 600 7022
Co-Chair/Co-editor: Bob Ray PESA Switching Systems, Inc. Postal: 330-A Wynn Drive Huntsville, AL 35805 USA Email: rray@pesa.com Phone: +1 256 726 9200 ext. 142
DESCRIPTION "The VDSL-LINE-MIB found in RFC 3728 defines objects for the management of a pair of VDSL transceivers at each end of the VDSL line. The VDSL-LINE-MIB configures and monitors the line code independent parameters (TC layer) of the VDSL line. This MIB module is an optional extension of the VDSL-LINE-MIB and defines objects for configuration and monitoring of the line code specific (LCS) elements (PMD layer) for VDSL lines using SCM coding. The objects in this extension MIB MUST NOT be used for VDSL lines using Multiple Carrier Modulation (MCM) line coding. If an object in this extension MIB is referenced by a line which does not use SCM, it has no effect on the operation of that line.
Naming Conventions:
Vtuc -- VDSL transceiver at near (Central) end of line Vtur -- VDSL transceiver at Remote end of line Vtu -- One of either Vtuc or Vtur Curr -- Current Atn -- Attenuation LCS -- Line Code Specific Max -- Maximum Mgn -- Margin PSD -- Power Spectral Density Rx -- Receive Snr -- Signal to Noise Ratio Tx -- Transmit
Copyright (C) The Internet Society (2005). This version of this MIB module is part of RFC 4069: see the RFC itself for full legal notices." REVISION "200504280000Z" -- April 28, 2005 DESCRIPTION "Initial version, published as RFC 4069." ::= { transmission 228 }
VdslSCMBandId ::= TEXTUAL-CONVENTION STATUS current DESCRIPTION "This data type is used as the syntax for the VDSL SCM Band Identity. Attributes with this syntax identify the SCM Band referred to. Specified as an INTEGER, the possible values are:
optionalBand (1) -- the optional Band range [25kHz - 138kHz] firstDownstreamBand (2) -- first Downstream Band firstUpstreamBand (3) -- first Upstream Band secondDownstreamBand (4) -- second Downstream Band secondUpstreamBand (5) -- second Upstream Band thirdDownstreamBand (6) -- third Downstream Band thirdUpstreamBand (7) -- third Upstream Band"
-- -- Single carrier modulation (SCM) configuration profile tables --
vdslLineSCMConfProfileBandTable OBJECT-TYPE SYNTAX SEQUENCE OF VdslLineSCMConfProfileBandEntry MAX-ACCESS not-accessible STATUS current DESCRIPTION "This table contains transmit band descriptor configuration information for a VDSL line. Each entry in this table reflects the configuration for one of possibly many bands of a single carrier modulation (SCM) VDSL line. For each profile which is associated with a VDSL line using SCM line coding, five entries in this table will exist, one for each of the five bands. Bands which are not in use will be marked as unused. These entries are defined by a manager and can be used to configure the VDSL line. If an entry in
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this table is referenced by a line which does not use SCM, it has no effect on the operation of that line." ::= { vdslLineExtSCMMibObjects 1 }
vdslLineSCMConfProfileBandEntry OBJECT-TYPE SYNTAX VdslLineSCMConfProfileBandEntry MAX-ACCESS not-accessible STATUS current DESCRIPTION "Each entry consists of a list of parameters that represents the configuration of a single carrier modulation VDSL modem transmit band.
A default profile with an index of 'DEFVAL', will always exist and its parameters will be set to vendor specific values, unless otherwise specified in this document.
All read-create objects defined in this MIB module SHOULD be stored persistently."
INDEX { vdslLineConfProfileName, vdslLineSCMConfProfileBandId } ::= { vdslLineSCMConfProfileBandTable 1 }
vdslLineSCMConfProfileBandId OBJECT-TYPE SYNTAX VdslSCMBandId MAX-ACCESS not-accessible STATUS current DESCRIPTION "The BandId for this entry, which specifies which band is being referred to." ::= { vdslLineSCMConfProfileBandEntry 1 }
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vdslLineSCMConfProfileBandInUse OBJECT-TYPE SYNTAX TruthValue MAX-ACCESS read-create STATUS current DESCRIPTION "Indicates whether this band is in use. If set to True this band is in use." ::= { vdslLineSCMConfProfileBandEntry 2 }
vdslLineSCMConfProfileBandCenterFrequency OBJECT-TYPE SYNTAX Unsigned32 UNITS "Hz" MAX-ACCESS read-create STATUS current DESCRIPTION "Specifies the center frequency in Hz" REFERENCE "T1E1.4/2000-011R3" -- Part 2, SCM ::= { vdslLineSCMConfProfileBandEntry 3 }
vdslLineSCMConfProfileBandSymbolRate OBJECT-TYPE SYNTAX Unsigned32 UNITS "baud" MAX-ACCESS read-create STATUS current DESCRIPTION "The requested symbol rate in baud." REFERENCE "T1E1.4/2000-011R3" -- Part 2, SCM ::= { vdslLineSCMConfProfileBandEntry 4 }
vdslLineSCMConfProfileBandConstellationSize OBJECT-TYPE SYNTAX Unsigned32 (0..16) UNITS "log2" MAX-ACCESS read-create STATUS current DESCRIPTION "Specifies the constellation size." REFERENCE "T1E1.4/2000-011R3" -- Part 2, SCM ::= { vdslLineSCMConfProfileBandEntry 5 }
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vdslLineSCMConfProfileBandTransmitPSDLevel OBJECT-TYPE SYNTAX Unsigned32 UNITS "-0.25 dBm/Hz" MAX-ACCESS read-create STATUS current DESCRIPTION "The requested transmit power spectral density for the VDSL modem. The Actual value in -0.25 dBm/Hz." REFERENCE "T1E1.4/2000-011R3" -- Part 2, SCM ::= { vdslLineSCMConfProfileBandEntry 6 }
vdslLineSCMConfProfileBandRowStatus OBJECT-TYPE SYNTAX RowStatus MAX-ACCESS read-create STATUS current DESCRIPTION "This object is used to create a new row or modify or delete an existing row in this table.
A profile activated by setting this object to `active'. When `active' is set, the system will validate the profile.
None of the columns in this row may be modified while the row is in the `active' state.
Before a profile can be deleted or taken out of service, (by setting this object to `destroy' or `notInService') it must be first unreferenced from all associated lines."
::= { vdslLineSCMConfProfileBandEntry 7 }
-- -- SCM physical band --
vdslLineSCMPhysBandTable OBJECT-TYPE SYNTAX SEQUENCE OF VdslLineSCMPhysBandEntry MAX-ACCESS not-accessible STATUS current DESCRIPTION "This table provides one row for each SCM Vtu band. This table is read only as it reflects the current physical parameters of each band. For each ifIndex which is associated with a VDSL line using SCM line coding, five entries in this table will exist, one for each of the five bands. Bands which are not in use will be marked as unused."
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::= { vdslLineExtSCMMibObjects 2 }
vdslLineSCMPhysBandEntry OBJECT-TYPE SYNTAX VdslLineSCMPhysBandEntry MAX-ACCESS not-accessible STATUS current DESCRIPTION "An entry in the vdslLineSCMPhysBandTable." INDEX { ifIndex, vdslLineSCMPhysBandId } ::= { vdslLineSCMPhysBandTable 1 }
vdslLineSCMPhysBandId OBJECT-TYPE SYNTAX VdslSCMBandId MAX-ACCESS not-accessible STATUS current DESCRIPTION "The BandId for this entry, which specifies which band is being referred to." ::= { vdslLineSCMPhysBandEntry 1 }
vdslLineSCMPhysBandInUse OBJECT-TYPE SYNTAX TruthValue MAX-ACCESS read-only STATUS current DESCRIPTION "Indicates whether this band is in use. If set to True this band is in use." ::= { vdslLineSCMPhysBandEntry 2 }
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vdslLineSCMPhysBandCurrCenterFrequency OBJECT-TYPE SYNTAX Unsigned32 UNITS "Hz" MAX-ACCESS read-only STATUS current DESCRIPTION "The current center frequency in Hz for this band." REFERENCE "T1E1.4/2000-011R3" -- Part 2, SCM ::= { vdslLineSCMPhysBandEntry 3 }
vdslLineSCMPhysBandCurrSymbolRate OBJECT-TYPE SYNTAX Unsigned32 UNITS "baud" MAX-ACCESS read-only STATUS current DESCRIPTION "The current value of the symbol rate in baud for this band." REFERENCE "T1E1.4/2000-011R3" -- Part 2, SCM ::= { vdslLineSCMPhysBandEntry 4 }
vdslLineSCMPhysBandCurrConstellationSize OBJECT-TYPE SYNTAX Unsigned32 (0..16) UNITS "log2" MAX-ACCESS read-only STATUS current DESCRIPTION "The current constellation size on this band." REFERENCE "T1E1.4/2000-011R3" -- Part 2, SCM ::= { vdslLineSCMPhysBandEntry 5 }
vdslLineSCMPhysBandCurrPSDLevel OBJECT-TYPE SYNTAX Unsigned32 UNITS "- 0.25 dBm/Hz" MAX-ACCESS read-only STATUS current DESCRIPTION "The transmit power spectral density for the VDSL modem." REFERENCE "T1E1.4/2000-011R3" -- Part 2, SCM ::= { vdslLineSCMPhysBandEntry 6 }
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vdslLineSCMPhysBandCurrSnrMgn OBJECT-TYPE SYNTAX Integer32 UNITS "0.25 dB" MAX-ACCESS read-only STATUS current DESCRIPTION "Noise margin as seen by this Vtu and band with respect to its received signal in 0.25 dB." ::= { vdslLineSCMPhysBandEntry 7 }
vdslLineSCMPhysBandCurrAtn OBJECT-TYPE SYNTAX Unsigned32 (0..255) UNITS "0.25 dB" MAX-ACCESS read-only STATUS current DESCRIPTION "Measured difference in the total power transmitted by the peer Vtu on this band and the total power received by this Vtu on this band in 0.25 dB." ::= { vdslLineSCMPhysBandEntry 8 }
} STATUS current DESCRIPTION "A collection of objects providing configuration information for a VDSL line based upon single carrier modulation modem." ::= { vdslLineExtSCMGroups 1 }
This document contains many definitions taken from an early version of the VDSL MIB [RFC3728]. As such, any credit for the text found within should be fully attributed to the authors of that document.
There are a number of management objects defined in this MIB module with a MAX-ACCESS clause of 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:
VDSL layer connectivity from the Vtur will permit the subscriber to manipulate both the VDSL link directly and the VDSL embedded operations channel (EOC) for their own loop. For example, unchecked or unfiltered fluctuations initiated by the subscriber could generate sufficient notifications to potentially overwhelm either the management interface to the network or the element manager.
Additionally, allowing write access to configuration data may allow an end-user to increase their service levels or affect other end- users in either a positive or negative manner. For this reason, the tables and objects listed above should be considered to contain sensitive information.
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:
Read access of the physical band parameters may provide knowledge to an end-user that would allow malicious behavior, for example the application of an intentional interference on one or all of the physical bands in use.
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).
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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 a 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.
[DSLFTR57] DSL Forum TR-057, "VDSL Network Element Management", February 2003.
[DSLFWT96] DSL Forum WT-096, "SCM Specific Managed Objects In VDSL Network Elements".
[ETSI2701] ETSI TS 101 270-1 V1.2.1, "Transmission and Multiplexing (TM); Access transmission systems on metallic access cables; Very high speed Digital Subscriber Line (VDSL); Part 1: Functional requirements", October 1999.
[ETSI2702] ETSI TS 101 270-2 V1.1.1, "Transmission and Multiplexing (TM); Access transmission systems on metallic access cables; Very high speed Digital Subscriber Line (VDSL); Part 1: Transceiver specification", February 2001.
[ITU9931] ITU-T G.993.1, "Very-high-speed digital subscriber line foundation", November 2001.
[ITU9971] ITU-T G.997.1, "Physical layer management for Digital Subscriber Line (DSL) Transceivers", July 1999.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2578] McCloghrie, K., Perkins, D., and J. Schoenwaelder, "Structure of Management Information Version 2 (SMIv2)", STD 58, RFC 2578, April 1999.
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[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.
[RFC2863] McCloghrie, K. and F. Kastenholz, "The Interfaces Group MIB", RFC 2863, June 2000.
[RFC3728] Ray, B. and R. Abbi, "Definitions of Managed Objects for Very High Speed Digital Subscriber Lines (VDSL)", RFC 3728, February 2004.
[T1E1311] ANSI T1E1.4/2001-311, "Very-high-bit-rate Digital Subscriber Line (VDSL) Metallic Interface, Part 1: Functional Requirements and Common Specification", February 2001.
[T1E1011] ANSI T1E1.4/2001-011R3, "VDSL Metallic Interface, Part 2: Technical Specification for a Single-Carrier Modulation (SCM) Transceiver", November 2001.
[T1E1013] ANSI T1E1.4/2001-013R4, "VDSL Metallic Interface, Part 3: Technical Specification for a Multi-Carrier Modulation (MCM) Transceiver", November 2000.
[RFC3415] Wijnen, B., Presuhn, R., and K. McCloghrie, "View-based Access Control Model (VACM) for the Simple Network Management Protocol (SNMP)", STD 62, RFC 3415, December 2002.
[RFC3410] Case, J., Mundy, R., Partain, D., and B. Stewart, "Introduction and Applicability Statements for Internet- Standard Management Framework", RFC 3410, December 2002.
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Authors' Addresses
Menachem Dodge ECI Telecom Ltd. 30 Hasivim St. Petach Tikva 49517, Israel
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