Data Model-Driven Management

By Benoit Claise, Joe Clarke, Jan Lindblad
May 15, 2019

␡

⎙ Print

< Back Page 6 of 15 Next >

Network Programmability with YANG: The Structure of Network Automation with YANG, NETCONF, RESTCONF, and gNMI

Learn More Buy

Data Model–Driven Management Components

Data model–driven management is built on the idea of applying modeling languages to formally describe data sources and APIs. This includes the ability to generate behavior and code from the models. YANG is the data model language of choice; it allows a modeler to create a data model, to define the organization of the data in that model, and to define constraints on that data. Once published, the YANG module acts as a contract between the client and server, with each party understanding how its peer expects it to behave. A client knows how to create valid data for the server and knows what data will be sent from the server. A server knows the rules that govern the data and how it should behave.

As displayed in Figure 2-4, which covers the data model–driven management components, once the YANG models are specified and implemented, a network management system (NMS) can select a particular encoding (XML, JSON, protobuf, thrift, you name it) and a particular protocol (NETCONF, RESTCONF, or gNMI/gRPC) for transport. Yes, there are differences in capabilities between the different protocols and, yes, there are some limitations in the combination of the encodings and protocols (marked by the arrows in the figure), and those are reviewed later in this chapter.

Figure 2.4 The Data Model–Driven Management Components

Typically, an orchestrator delivers service automation through multiple protocols/encodings. Based on the encoding and protocol selections, you can generate behavior or code to access the YANG objects on managed devices (for example, in Python, C++, Go, or basically any programming language). Note that as time passed, more and more arrows were added to this figure. In the end, all combinations become possible.

Orchestrators use code generation in their automation. A good showcase to demonstrate data model–driven management concepts and how the related code is rendered might be an open source tool such as the YANG Development Kit (YDK), which provides APIs directly based on YANG models and ready to use in scripts. The main goal of YDK is to reduce the learning curve involved with YANG data models by expressing the model semantics in an API and abstracting the protocol/encoding details. Example 2-1 shows a sample Python program illustrating the use of a generated API, oc-interfaces.py, which in turn is derived from the open-config-interfaces YANG module.

EXAMPLE 2-1 PYTHON YDK EXAMPLE OF CONFIGURING A BGP SESSION

from __future__ import print_function
from ydk.types import Empty, DELETE, Decimal64
from ydk.services import CRUDService
import logging

from session_mgr import establish_session, init_logging
from ydk.models.openconfig.openconfig_interfaces import Interfaces
from ydk.errors import YError



def print_interface(interface):
    print('*' * 28)
    print('Interface %s'%interface.name)

    if interface.config is not None:
        print('  config')
        print('     name:-%s'% interface.config.name)
        if interface.config.type is not None:
            print('     type:-%s'%interface.config.type.__class__)
        print('    enabled:-%s'%interface.config.enabled)

    if interface.state is not None:
        print('  state')
        print('     name:-%s'% interface.state.name)
        if interface.state.type is not None:
            print('     type:-%s'%interface.state.type.__class__)
        print('     enabled:-%s'%interface.state.enabled)
        if interface.state.admin_status is not None:
            enum_str = 'DOWN'
            if interface.state.admin_status == interface.state.AdminStatusEnum.UP:
                enum_str = 'UP'
            print('     admin_status:-%s'%enum_str)
        if interface.state.oper_status is not None:
            oper_status_map = { interface.state.OperStatusEnum.UP : 'UP',
                                interface.state.OperStatusEnum.DOWN : 'DOWN',
                                interface.state.OperStatusEnum.TESTING : 'TESTING',
                                interface.state.OperStatusEnum.UNKNOWN: 'UNKNOWN',
                                interface.state.OperStatusEnum.DORMANT : 'DORMANT',
                                interface.state.OperStatusEnum.NOT_PRESENT :
                                'NOT_PRESENT',
                                }
            print('     oper_status:-%s'%oper_status_map[interface.state.oper_status])

        if interface.state.mtu is not None:
            print('      mtu:-%s'%interface.state.mtu)
        if interface.state.last_change is not None:
            print('      last_change:-%s'%interface.state.last_change)

        if interface.state.counters is not None:
            print('     counters')
            print('        in_unicast_pkts:-%s'%interface.state.counters
                           .in_unicast_pkts)
            print('        in_octets:-%s'%interface.state.counters.in_octets)
            print('        out_unicast_pkts:-%s'%interface.state.counters
                           .out_unicast_pkts)
            print('        out_octets:-%s'%interface.state.counters.out_octets)
            print('        in_multicast_pkts:-%s'%interface.state.counters
                           .in_multicast_pkts)
            print('        in_broadcast_pkts:-%s'%interface.state.counters
                           .in_broadcast_pkts)
            print('        out_multicast_pkts:-%s'%interface.state.counters
                           .out_multicast_pkts)
            print('        out_broadcast_pkts:-%s'%interface.state.counters
                           .out_broadcast_pkts)
            print('        out_discards:-%s'%interface.state.counters.out_discards)
            print('        in_discards:-%s'%interface.state.counters.in_discards)
            print('        in_unknown_protos:-%s'%interface.state.counters
                           .in_unknown_protos)
            print('        in_errors:-%s'%interface.state.counters.in_errors)
            print('        out_errors:-%s'%interface.state.counters.out_errors)
            print('        last_clear:-%s'%interface.state.counters.last_clear)

        if interface.state.ifindex is not None:
            print('     ifindex:-%s'%interface.state.ifindex)

    print('*' * 28)

def read_interfaces(crud_service, provider):

    interfaces_filter = Interfaces()

    try:
        interfaces = crud_service.read(provider, interfaces_filter)
        for interface in interfaces.interface:
            print_interface(interface)
    except YError:
        print('An error occurred reading interfaces.')


def create_interfaces_config(crud_service, provider):

    interface = Interfaces.Interface()
    interface.config.name = 'LoopbackYDK'
    interface.name = interface.config.name

    try:
        crud_service.create(provider, interface)
    except YError:
        print('An error occurred creating the interface.')



if __name__ == "__main__":
    init_logging()
    provider = establish_session()
    crud_service = CRUDService()
    read_interfaces(crud_service, provider)


    provider.close()
exit()

Obviously, other tools for code generation exist; for example, in the world of OpenConfig, see http://www.openconfig.net/software/.²⁰

Notice that the primary source of information to generate code is the set of YANG modules. This is the reason why the IETF and the industry in general are spending so much energy specifying these YANG modules as precisely as possible.

< Back Page 6 of 15 Next >

🔖 Save To Your Account

InformIT Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.

Privacy Notice

Overview

Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information

To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.

Surveys

Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.

Newsletters

If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information

Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.

Security

Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.

Children

This site is not directed to children under the age of 13.

Marketing

Pearson may send or direct marketing communications to users, provided that

Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
Such marketing is consistent with applicable law and Pearson's legal obligations.
Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information

If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.

Choice/Opt-out

Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information

Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents

California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure

Pearson may disclose personal information, as follows:

As required by law.
With the consent of the individual (or their parent, if the individual is a minor)
In response to a subpoena, court order or legal process, to the extent permitted or required by law
To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
To investigate or address actual or suspected fraud or other illegal activities
To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.

Links

This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact

Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice

We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020

Email Address