Home > Articles > Networking > Network Administration & Management

This chapter is from the book

Linked Overviews

An increasingly common problem faced by NMS software developers is implementing network management support for new NE features, such as MPLS. The following four steps provide a linked overview of the management aspects of an NE feature:

  1. Acquire a basic understanding of the managed technology—what it does, how it operates, and so on. For MPLS, the basic purpose is to carry traffic across an MPLS core, so connections (LSPs and tunnels) are important. These tunnels can be traffic-engineered and can also support QoS, so path and resource blocks (more on these later in the chapter) are needed.

  2. Use the EMS to get an understanding of how the NE provides the feature; for example, for MPLS, the user can separately create objects like paths and resource blocks. Then, these can be combined to create MPLS LSPs or tunnels. User manuals are often very useful during this process.

  3. View the relevant MIBs using a MIB browser.

  4. Write simple test code (e.g., in Java or C++) to view and modify the MIB objects.

Step 4 essentially automates the actions in steps 2 and 3. The software produced in step 4 can then form the basis of Java classes that can eventually be imported into the finished NMS. The final stage in development is then adding code to the NMS to implement the overall MPLS management feature (i.e., FCAPS). An important observation about the above is that it depicts NMS development as a type of reverse engineering. If network management is provided at the end of NE development, then it has a reverse engineering flavor. If the two occur in parallel, then no real reverse engineering effort is required. We therefore view a linked overview as the resulting knowledge emanating from following the above four steps.

03inf01.gif

 

Some vendors provide simultaneous releases of both NE firmware and NMS software. In other words, NE and NMS development are inextricably interwoven.

Step 1 can be assisted using the RFCs on the IETF Web site [IETFWeb]. The other steps are carried out in conjunction with the NEs themselves. Some examples of linked overviews now follow.

Developer Note: An ATM Linked Overview

Many technologies can seem extremely complex at first, and then, as the learning curve progresses, the essential patterns begin to emerge. ATM [Tanenbaum1996], [ATMObjects] is a good example. Stripped down to its bare (linked overview) essentials:

  • ATM is a layer 2 protocol suitable for deployment in a range of operational environments (in VLANs and ELANs, in the WAN, and also in SP networks).

  • ATM offers a number of different categories and classes of service. The required service level is enforced by switches using policing (traffic cop function), shaping (modifying the traffic interarrival time), marking (for subsequent processing), and dropping.

  • Traffic is presented to an ATM switch and converted into a stream of 53-byte ATM cells.

  • The stream of cells is transmitted through an ATM cloud.

  • A preconfigured virtual circuit dictates the route taken by the cell stream. Virtual circuits can be created either manually or using a signaling protocol. If no virtual circuit is present then PNNI can signal switched virtual circuits (SVCs).

  • The virtual circuit route passes through intermediate node interfaces and uses a label-based addressing scheme.

  • Bandwidth can be reserved along the path of this virtual circuit in what is called a contract.

  • Various traffic engineering capabilities are available, such as dictating the route for a virtual circuit.

This list provides an overview of ATM technology. It joins (or links) the principal components needed for managing ATM. From this list, the essential ATM managed objects can be derived:

  • ATM nodes

  • A virtual circuit (switched, permanent, or soft) spanning one or more nodes

  • A set of interfaces and links

  • A set of locally significant labels used for addressing

  • An optional route or designated transit list

  • A bandwidth contract

  • Traffic engineering settings

  • QoS details

This is a good start on the road to defining managed objects for the support of ATM. It points to the merit of studying documents from the ATM Forum and ITU-T Broadband ISDN. The next stage (step 2) would be to experiment with the EMS of an ATM switch and see the above objects in practice, e.g., creating PVCs and SPVCs. Next, we would examine the MIB objects (step 3) [ATMObjects] involved in step 2, and then produce software (step 4) to read and write instances of those objects.

Developer Note: An IP Linked Overview

The convergence of layers 2 and 3 (e.g., connection-oriented operation of layer 3 networks) has forced the need for knowledge about IP onto practically everyone's agenda. IP is often used as an abbreviated form of TCP/IP, and this is the way it is used in this book. Like UNIX and Ethernet, IP is one of the great software engineering feats of the 20th century. Both are in widespread use (although UNIX, unlike DOS or Windows, has no single standard implementation) and have withstood the test of time. IP has a steep learning curve, but it can be summarized into a linked overview as follows:

  • IP is packet-based—IP nodes make forwarding decisions with every packet.

  • IP is not connection-oriented.

  • IP provides a single class of service: best effort.

  • IP does not provide traffic engineering capabilities.

  • IP packets have two main sections: header and data.

  • IP header lookups are required at each hop (with the present line-rate technology, lookups are no longer such a big issue. Routing protocol convergence may cause more problems).

  • IP devices are either hosts or routers (often called gateways).

  • Hosts do not forward IP packets—routers do.

  • IP devices have routing tables.

  • IP operates in conjunction with other protocols, such as OSPF, IS-IS, Border Gateway Protocol 4 (BGP4), and Internet Control Message Protocol (ICMP).

  • Large IP networks can be structured as autonomous systems made up of smaller interior areas or levels.

So, the essential managed objects of IP are:

  • IP nodes (routers, hosts, clients, servers)

  • IP interfaces

  • IP subnets

  • IP protocols (routed protocols such as TCP/IP and routing protocols such as OSPF and IS-IS)

  • Interior Gateway Protocol (IGP) areas (OSPF) or levels (IS-IS)

  • Exterior Gateway Protocol (EGP) autonomous systems

The next stage (step 2) would be to experiment with the EMS of an IP router (or an IP/MPLS switch) and see the above objects in practice, for example, creating IP interfaces and subnets, and configuring routing protocols. Next, we would examine the MIB objects (step 3) involved in step 2 and then produce software (step 4) to read and write instances of those objects.

Embracing Short Development Cycles

The need for immediate ROI is prompting a demand for innovative management system solutions. Enterprises must be able to leverage their investments for both productivity (easier operation of networks) and financial gains (smoother business processes). This can result in shorter NMS software development cycles, which in turn requires a modified approach to producing NMS:

  • Reduced feature sets in more frequent releases

  • Foundation releases

  • Good upgrade paths

  • Getting good operational feedback from end users

If a management system release occurs every four or five months, then it is no longer necessary for every single requirement to be fulfilled. Instead, requirements can and probably should be prioritized over a range of releases. When a new technology is adopted and implemented on a range of NEs (such as VoIP or FR interworking), then only the mandatory management facilities should be implemented first. The rest can follow later. The first release becomes a foundation for the later ones. In time, the initial reduced feature set grows steadily to become part of a sophisticated end-user solution. Not all users would necessarily upgrade—just the ones who need the new foundation release features. The developers would carry out the bulk of the testing. As the releases occur, the user's data has to be carefully protected and upgraded as necessary. So, upgrade issues (such as scalability-related database schema changes) increasingly have to become part of the bread-and-butter of development.

Implicit in all this is the end user becoming a development partner providing valuable operational feedback. The user receives regular, reliable releases, and the vendor sees fast return on development investment. Another benefit is that developers gain experience and expertise with each of the minor releases.

Minimizing Code Changes

Perhaps one of the most difficult software development skills to acquire is the ability to resist changing code. This applies to good and bad code, old and new. A crucial skill for developing NMS software is the ability to make small, focused fixes for specific problems without introducing new bugs. It can be extremely difficult to resist making simultaneous changes to neighboring code, but it is a vital discipline. Unnecessary code changes introduce bugs and increase the need for testing. Every code change should be fully tested as part of a mandatory change control process.

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.

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