3. Introduction
• YANG is an abbreviation for “Yet Another Next Generation”
• YANG is a data modelling language for NETCONF protocol
• YANG was published as RFC 6020 in October 2010
• YANG was developed by the NETMOD group of the IETF force
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4. What is IETF ?
• IETF develops and promotes voluntary internet
standards
• IETF is an open standard organisation with no
formal membership or membership requirements
• IETF was an activity supported by the US
government but since 1993, it has operated as a
standard development function under “Internet
Society”
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5. What is Data Modelling ?
• Data modelling is the process of creating a data model for an
information system
• It is a process used to define and analyse data requirements
needed to support the business process
• Data modelling defines not just elements but also the structure
and relationship between them
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6. Data Modelling structure
• The figure illustrates
the way data models are
developed and used
today.
• A conceptual data model
is developed based on
the data requirements
for the application that
is being developed.
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7. Example of data modelling
• This is a screenshot of a data
modelling example
• It clearly shows us the
relationship between different
models and the type of
relationship (one-to-many or
many-to-one) between each
model
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8. History
• Many network management protocols have associated data modelling
languages
• The first widely developed internet standard for network
management was Simple Network Management Protocol (SNMP)
• The data modelling language associated with SNMP was Structure of
Management Information (SMI)
• The SMI language was itself based on the 1998 version of Abstract
Syntax Notation One (ASN.1)
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9. Abstract Syntax Notation One (ASN.1)
• ASN.1 is a standard and notation that describes rules and
structures in Telecom and Computer Networking
• ASN.1 is used for representing, encoding and transmitting data in
Networking
• ASN.1 defines the abstract syntax of information but does not
restrict the way the information is encoded
• A particular new application of ASN.1 is Fast Infoset
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10. Structure of Management Information(SMI)
• SMI is an adapted subset of ASN.1
• The Structure of Management Information (SMI) is a framework that
describes the basic types of information that can be manipulated
by SNMP
• SMI operates in Simple Network Management Protocol (SNMP)
• SMI provides a skeleton that specifies the basic format and
hierarchy of management data but does not describe the objects
that can be managed
• SMI defines the modules of related managed objects in a
Management Information Base (MIB)
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11. SMI Sample
• To ensure that object
identifiers are unique, each
organization is responsible
for a particular section of
the OID tree.
• Just as ISO and CCITT have
responsibility for their
portions, the Internet
Activities Board (IAB) has
responsibility for the
internet portion.
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12. Simple Network Management Protocol (SNMP)
• SNMP is an internet standard protocol
• SNMP is used for collecting and organising information about
managed devices on IP networks
• Devices supporting SNMP are:
Routers
Switches
Servers
Workstations
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13. SNMP Applications
• SNMP is widely used in network management
systems to monitor network-attached devices
for conditions that warrant administrative
attention
• SNMP is a component of the Internet Protocol
(IP) suite as defined by the Internet
Engineering Task Force (IETF)
• SNMP operates in the Application Layer of
the Internet Protocol Suite (Layer 7 of OSI
model)
• SNMP agent receives requests on UDP port 161
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14. SNMP Network
• In typical uses of SNMP one or
more administrative computers,
called managers, have the task of
monitoring or managing a group of
hosts or devices on a computer
network
• An SNMP-managed network consists
of three key components:
Managed device
Agent
Network Management Station (NMS)
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15. Issues with SNMP
• SNMP is not purpose-built for configuring network
• SNMP lacks standard MIBs for configuring networks
• SNMP is not efficient to play back configurations
• SNMP is not fast either. For example, when returning routing
tables, it is very slow
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16. Advantages of NETCONF and YANG
• Single focus is configuration
• They use standard XML format, which uses a
native “get config” command which return
only configuration data
• “Network configuration” over “Box
configuration”
• NETCONF has the ability to support
transaction
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17. NETCONF
• NETCONF is a network management protocol developed and
standardized by IETF
• NETCONF was published in December 2006 as RFC 4741 and revised in
June 2011 as RFC 6241
• NETCONF provides mechanisms to install, manipulate and delete
configuration of network devices
• NETCONF operates on the top of the Remote Procedure Call (RPC)
protocol layer
• NETCONF protocol uses an Extensive Markup Language (XML)
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18. NETCONF superior to SNMP
• SNMP was not being used to configure network equipment but
was mainly being used for network management
• IETF got together with network operators to solve this
issue
• During this time, Juniper Networks used an XML-based net
management approach
• These two events together led the IETF in may 2003 to form
the NETCONF working group
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19. NETCONF Protocol Layers
• The NETCONF protocol can be conceptually partitioned into four
layers:
1. The Content layer consists of configuration data and
notification data
2. The Operations layer defines a set of base protocol operations
to retrieve and edit the configuration data
3. The Messages layer provides a mechanism for encoding remote
procedure calls (RPCs) and notifications
4. The Secure Transport layer provides a secure and reliable
transport of messages between a client and a server
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20. NETCONF Protocol Layers
• The NETCONF protocol has been
implemented in network devices
such as routers and switches
by some major equipment
vendors
• One particular strength of
NETCONF is its support for
robust configuration change
transactions involving a
number of devices
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21. NETCONF and YANG
• NETCONF is the standard for installing,
manipulating and deleting configuration
of network devices while YANG is used
to model both configuration and state
data of network elements
• Soon after the development of NETCONF
protocol, IETF realised that a data
module language was needed to define
data modules in NETCONF
• The syntactic structure and baseline
system was originally borrowed from
SMIng
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22. YANG
• YANG structures the data definitions into tree structures and
provides many modelling features
• YANG also includes an extensible type system, formal separation
of state and configuration data and a variety of syntactic and
semantic constraints
• YANG data definitions are contained in modules and provide a
strong set of features for extensibility and reuse
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23. Publication
The YANG data modelling language
was developed by NETMOD working
group in the Internet
Engineering Task Force (IETF)
and was published as RFC 6020 in
October 2010
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24. YANG Module Structure
A YANG module is made up of:
• Header Information
• Imports and Includes
• Type Definitions
• Configurational and
operational data declarations
• Action (RPC) and notification
declarations
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26. YIN & YANG
• In Chinese philosophy, YIN and YANG describe how opposite or contrary
forces are actually complementary, interconnected and interdependent
in the natural world
• YIN is the XML version of YANG
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27. Yang-ide
• An integrated development environment (IDE) is a software
application that provides comprehensive facilities to computer
programmers for software development
• An IDE normally consists of a source code editor, build
automation tools and a debugger
• Most modern IDEs have intelligent code completion
• YANG IDE is an integrated development environment for Yang
language
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28. Software required
Software tools required to implement a YANG-IDE are as follows:
1. Eclipse SDK 4.4
2. Java SE Development Kit 7
3. Apache Maven
4. Git
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29. Steps to implement
Steps to implement yang-ide are as follows:
1. Clone the project
2. Import the projects into Eclipse
3. Configure Eclipse
4. Build the project by Maven
5. Run YANG IDE from Eclipse Development Environment
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30. OpenDaylight and YANG
• OpenDaylight heavily uses YANG to model
any data, notification or Remote
Procedure Call (RPC) that goes between
different modules
• This module is provided to the MD-SAL
platform and then loaded in Karaf
• MD-SAL creates two data stores for this
module i.e.:
1. Config data store
2. Operational data store
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31. Ericsson and YANG IDE
• Ericsson has started to develop
an IDE plugin to support the YANG
language
• Currently it uses pyang to
analyse the yang model file
• It does:
Syntax Highlighting
Invocation of pyang on the yang
file
Analysing the pyang output
Marking errors
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32. YANG and Amdocs
• Amdocs has announced its own plan for NFV
Orchestration
• This NFV Orchestration is meant to be the
central brain of a new NFV network
• The service models are represented in YANG
• One example would be a virtual function to
block distributed denial-of-service (DDoS)
attacks
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34. YANG and YumaWorks
• YumaWorks is a leader in YANG-driven automation
tools for NETCONF, CLI and RESTCONF network
management interfaces
• The YumaPro Server supports the complete
NETCONF protocol
• Any protocol operation, database object or
notification message can be easily added to the
server by providing a YANG data model defining
the API
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35. YANG and Tail-f
• Tail-f Systems provides multi-vendor network
automation software for traditional and Software
Defined Networks (SDN)
• Tail-f are leaders in the development of
configuration management software based on the
NETCONF and YANG standards
• Tail-f Systems was the first company to introduce
100% YANG (RFC 6020) compliant software applications
and tools
• YANG allows Tail-f Systems customers to build more
robust and resilient products in less time
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36. ConfD by Tail-f
• ConfD is the leading commercial
development platform to take
advantage of NETCONF and YANG
• As a way to expand adoption of
NETCONF and YANG, Tail-f is
providing a free version of ConfD
• Large service providers, such as
AT&T and Deutsche Telekom have a
strong preference for the NETCONF
and YANG standards
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38. YANG in Telecom
Companies supporting NETCONF/YANG are as
follows:
Brocade Communications Systems Inc.
Cisco Systems Inc.
Juniper Networks Inc.
Ericsson-LG
Amdocs Inc.
Nokia Networks
Alcatel-Lucent
AT&T Inc.
Deutsche Telekom
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39. Future Implementations
• SDN has provided a shift away from Hardware
towards software and services
• RESTCONF is an IETF draft that describes how to
map a YANG specification
• RESTCONF is not intended to replace NETCONF but
rather provide an additional simplified interface
• NETCONF and YANG are powerful tools with a bright
future for SDN/NFV
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