DLMSUA TPAK1_Intro

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IEC 62056 DLMS/COSEMworkshopPart 4 Main
concepts
Metering, Billing/CRM Asia 13-14th May 2009,
Bangkok Gyozo Kmethy, DLMS UA, President
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Contents

• Aplication modelling Messaging Data transport
• Model properties
• Messaging properties
• Data transport protocol properties
• Data security
• Opennes
• Manageability
• International standardization
• Interoperability
• Companion specifications
• Conformance certification
• Summary

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Vocabulary

• DLMS, Device Language Message Specification
• application layer protocol
• generalized concept for abstract modelling of
  communication entities specifies abstract
  object-related services and protocols
• COSEM, Companion Specification for Energy
  Metering
• data model comprises metering domain specific
  interface objects to model the functionality of
  the meter, with
• OBIS, the Object identification system used for
  object naming
• xDLMS (extended DLMS)
• application layer protocol extension to DLMS
• specifies how to build messages to access
  attributes and methods of COSEM objects

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The 3 (and a ½) step approach

• Data model, to view the meter functionality at
  its interface(s)
• COSEM objects
• OBIS Identification system
• Messaging method to communicate with the model
  and to represent data as a series of bytes
  (APDUs)
• Transportation method to carry the messages
  between the metering equipment and the data
  collection system

Separation of application model and protocol
orthogonality
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IEC 62056 DLMS/COSEM
Application data modelling
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Wide range of applications
Energy / demand tariffs
Billing (historical data)
Load profiles, data series
Instantaneous values
Power quality
Linetransfo losses
and many more
Gas energy measurement
I/O Control
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Application - Model - Protocol
Energy /demand
Billing
Load profiles
Gas conversion
Instantaneous / PQ
Access control
I/O control
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Object modelling
The NAME attributeidentifies the data
NAME
Any real-world things can be described by some
attributes
Attribute 1
Attribute 2
Each attribute has a meaning, a data type and a
value range
...
Using the object means
Attribute n
...to read or write the attributes
Method 1
Methods allow performing operations on attributes
...
Method n
...to invoke the methods
Attributes and methods constitute an object
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Modelling, from reality to abstraction
Template

• All data in the meter are mapped to objects
• The model provides the meters functional view
• Similar objects make up an interface class (IC)
• Each IC has a specific set of attributes and
  methods
• All ICs are accessed with the same xDLMS services

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Object model common for all energy types
IC template
Interface class
Instances
Three phase import active energy 1.0.1.8.0.255 401
53 kWh
S Li A total
Value
scaler_unit
Register 1
Forward undisturbed meter volume 7.0.1.0.0.255,
7086 m3

• Abstract objects e.g. service parameters,
  clock, schedules, scripts, communication channel
  setup
• Energy type specific objects

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OBIS data identification system
EDIS 'Wertegruppe'
M -
KK
GG .
AA
. T
VV
OBIS 'value group'
A
B
C
D
E
F

• Six value groups in a hierarchical structure
• Meaningful combinations standardised
• See Object def. tables
• Reduced codes display and standard readout

0...255Quantity
0..126Historical values
0...64Channel
0...255Classification e.g. tarification
0...15Medium
0...255Processing e.g. integration
Example
1 Electricity
1 Channel
1 S Li A
8Time int. 1
2 Rate 2
255 Current
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Flexibility Tailor made meters from standard
blocks

• Standard building blocks to build simple or
  complex meters
• Mandatory objects 2
• Logical Device Name, Association
• Residential meters few 10 objects
• Industrial meters few 100 objects

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Self-description at object level
Hold configuration identification data
Holds list oflogical devices
Hold communication channel setup info
Identifies the source of the data

• Hold the list of objects available with version
  info and access rights
• Provide context information

Hold measurement results
Each attribute delivers type and value
Objective minimize dependence on manufacturer
specific information
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Innovation and competition

• To support innovation and competition, specific
  elements are allowed
• manufacturer specific
• country specific
• consortia specific (e.g. SELMA)
• Specific elements may be
• specific instances of standard ICs (specific OBIS
  code)
• specific attributes or methods
• specific interface classes
• Information on specific elements has to be made
  available
• For standard features, manufacturer specific
  hacks are not allowed requires discipline

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Future proofness

• Extensions to meet new requirements, while
  maintaining compatibility
• new OBIS codes
• new versions of existing ICs object list
  provides version
• new ICs common messaging services for all
  existing and future classes
• extension of object model does not affect
  messaging and protocols
• extension of protocols does not affect the model

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Object model of a simple meter
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COSEM model properties summary

• Data modelling COSEM interface objects
• Multi-energy Common model for all energy types
• Self-descriptive list of objects, access to
  attributes/methods, data types no dependence on
  manufacturer information
• Efficient
• data can be organized to profiles spreadsheets
• data can be selectively accessed
• Data identification OBIS codes (logical name)
• All energy types
• Wide range of applications
• Unambiguous data identification

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IEC 62056 DLMS/COSEM
Messaging
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Messaging

• Transform object information to messages that can
  be transported
• Read / Write attributes
• Invoke methods
• To access them, they must be referenced
• Logical name referencing
• Short name referencing
• COSEM services are carried by xDLMS APDUs
• specified using ASN.1 abstract syntax
• encoded in A-XDR, IEC 61334-4-41

ltGetResponsegt ltGetResponsenormalgt
ltInvokeIdAndPriority Value"81" /gt ltResultgt
ltDatagt ltOctetString
Value"0101480700FF" /gt lt/Datagt
lt/Resultgt lt/GetResponsenormalgt lt/GetResponsegt
C4 0181 00 0906 0101480700FF
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Referencing Logical name or Short name
Read / Write / Unconfirmed Write named variable

• Interoperability negotiation of contexts and
  conformance block (list of services)

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Common services for all objects
GET
SET
ACTION

• Client-server environment
• Request identifies the (list of) data selective
  access possible
• Response supplies the data with data type
• Requests and responses must be paired in the DCS
• Event notification
• Common service set for all objects
• new interface classes can be easily added

Object
Read
Name
Attribute 1
Write
...
Attribute n
UnconfWrite
Method(s)

• Interoperable and future proof

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Messaging properties - summary

• Messaging xDLMS
• Application layer protocol
• Media independent services, common for all COSEM
  objects
• Efficiency selective access
• Negotiable contexts and capabilities
• Interoperability data type always conveyed
• Compact encoding using A-XDR (IEC 61334-6)
• Alternative messaging methods may be specified in
  the future (e.g. XML files)

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IEC 62056 DLMS/COSEM
Data transport
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Client-server environment
Profile 1
Profile 2
Profile n

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Data access and transport

• services to access the objects

• and protocols to transport the information

GET
COSEM Application
COSEM Application
SET
COSEM Application
...
...
...
Data link layer
ACTION
Data link layer
Data link layer
Physical layer
Physical layer
Physical layer
Report
COMM. MEDIA
C4010009060101480700FF
Value
Type
Result (success)
Service
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Communication profiles

• Application layer common in any communication
  profile
• connection between the metering and data
  collection applications
• prepares the messages for transport
• encoding,
• block transfer
• cryptographic protection

Profile 1
Profile 2
Profile n
Lower layersMedia 1PSTN, GSM
Lower layersMedia 2TCP/IP
Lower layersMedia n
Lower layers ensure that he messages are
correctly delivered
Identification of the profile used by the meter
ensures interoperability (available in 3-layer
HDLC profile)
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DLMS/COSEM communication profiles
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DLMS/COSEM security toolbox

• Access control
• role-based access list of objects, access
  rights
• Access security
• peer authentication
• client only (LLS) or
• client / server (HLS)
• Security event logs
• Data transfer security

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Access control
Utility A device
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Access security

• Authentication identification of the peers
  before data exchange
• Partners are identified by their addresses
  (Service Access Point)
• no security public access, no identification
  takes place
• LLS, Low Level Security Server identifies the
  Client, by password
• HLS, High Level Security mutual identification
• exchange challenges
• exchange result of secret processing
• Different Associations may use different
  Authentication contexts
• All Association events may be logged in Event
  logs

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Data transport security

• Provide cryptographic protection for messages
  during transport
• authentication to ensure integrity and
  authenticity (legitimate source)
• encryption to ensure confidentiality
• authenticated encryption

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Security implementation (1)

• Association objects control acces to data
  represented by the objects
• Security setup objects control security policy
  and manage keys

• Association Control Service Element (ACSE)
  controls contexts
• Application context
• LN or SN referencing
• conformance block
• ciphered / unciphered APDUs
• Authentication context
• One way / two way peer authentication (LLS /
  HLS)
• Security context controls ciphering, as defined
  by the security setup object

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Security
implementation (2)

• xDLMS ASE builds the messages
• Symmetric key algorithm Advanced Encryption
  Standard (AES), 128 bit key, Galois/Counter Mode
  (NIST 800-38D)
• Plain message
• Authenticated message for integrity and/or
• Encrypted message for confidentiality
• AES Key wrapping

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Security key management
DCS
Concentrator

• Encryption keys
• Global key used in several sessions (AAs)
  unicast - broadcast
• global unicast key encrypts dedicated key
• Dedicated key used in a single session (AA),
  then destroyed
• Authentication key (optional with GCM)
• Global, unicast and broadcast
• Master key pre-established, used only to wrap
  global keys

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Openness

• Specification is
• publicly available
• internationally standardised IEC, CENELEC, CEN
• no IP rights apply on any standards
• DLMS UA membership open to all at nominal fee
• participation in technical work
• training and technical support
• conformance testing is available at equal and
  fair terms
• forum for exchanging best practices
• No royalties
• Supported by many meter and system providers
  worldwide

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Manageability

• Role based access via Associations
• possibility to change scope of access
• various contexts and security policies
• Data organization and access tools
• profiles to get many data with a single request
• list commands, to minimize round trips
• Download of schedules
• Invocation of scripts
• Firmware download and activation
• Events and alarms
• EventNotification
• Matching communication network properties
• baud rates, window sizing, segmentation, block
  transfer

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International standardisation
Market requirements identified
DLMS UA WGs work out solutions
DLMS UA Books amended
Conformance testing extended
Intl standardizationlaunched

• DLMS UA is IEC TC 13 WG 14 liaison partner
• Acts as a pre-standardization and maintenance body

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Inter...what?

• Interoperability ability of diverse systems to
  work together
• syntactic ability to exchange data - protocols,
  formats
• semantic data exchange produces (agreed) useful
  results
• Interconnectivity all, what has to be connected,
  can be connected (physical and abstract level)
• Interchangeability elements providing the same
  function
• Reaching true interoperability
• open international standards
• access without restricitions
• companion standards to reduce options, and to
  specify project specific elements that cannot be
  specified internationally
• conformance testing
• partnership and co-operation
• discipline

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Companion specification

• International standards
• specify what can be agreed on
• specify few mandatory elements
• leave choices for flexibility
• Companion standardss
• restrict choices to optimize performance and
  costs
• specify elements that must be present to support
  project use cases
• specify project specific elements (e.g. events)
• specify processes
• facilitate achieving interoperability
• should be jointly specified by project
  participants

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Conformance testing

• Purpose to verify correct implementation in
  meters (DLMS/COSEM servers)
• Protocol and object model tests
• Helps product development
• pptional log module
• Helps system integration
• Self testing or third party testing
• Accessible to any DLMS UA member under fair and
  equal terms

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Conformance testing certification

• Test plans Certification DLMS UA
• Sales Görlitz Euro DCS
• 25 self-test, 4 third party test labs
• 102 meter types, 32 manufacturers,

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• Certificates listed at www.dlms.com
• Meter type LDN
• Manufacturer
• Test house
• Test information
• Test report is available from the manufacturer

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DLMS/COSEM The AMI standard of first choice

• Data models, messaging methods and protocols,
  with enhanced security, for meter data exchange
• Mult-utility and multi-media
• Self-descriptive, negotiable features
• Efficient data organization and access
• Simple or complex meters, from standard building
  blocks
• Covers smart metering needs
• Balance between flexibility and overhead
• Open, international standard, widely supported
• Supports innovation and competition
• Future proof
• Testable interoperability

in metering, we speak the same language