Home > Articles > Networking

VRRP Overview

  • Print
  • + Share This
This chapter is from the book

2.11  Case Studies

So far we defined and clarified VRRP concepts using simple configurations to keep the focus on the understanding of the protocol. Now that we have covered enough ground as an overview, we consider some typical VRRP deployment cases and call attention to some economic, risk-management aspect of the specific configuration. To do that we'll use different portions of the enterprise network we introduced at the beginning of this chapter in Figure 2-1. For the sake of facilitating the discussions, we use some made-up product names (MRM 100, MRM 5000, etc.) to create a context in which we can cover the trade-off considerations within a product line or a product category. With the same motivation, we also attribute some features to the products under discussion (support for dial-on-demand, filtering capabilities, etc.) so that the rationales for the described configurations become clearer.

2.11.1  Dial Backup and No Load Sharing

The first standard configuration in the branch offices of the enterprise network under study consists of three routers: one high-end model and two low-end models of the same product line. The high-end model is connected to the cloud through a Data Service Unit/Customer Service Unit (DSU/CSU) using leased lines: T1 or T3. The router MRM 5000 shown in Figure 2-14 represents such a configuration.

Figure 2-14FIGURE 2-14. Dial backup without load sharing


MRM5000 is the gateway of the branch office to the cloud and through the cloud to the Corporate Center. If it were not backed up, the failure of MRM 5000 would cause the branch office to lose all its network connectivity to the external world and thus to become almost unoperational, since all parts numbers and sales prices are stored in the Corporate Data Center. The economics of the company do not permit the purchase of another high-end router in addition to the lease of another T1 line for typical branch offices. For that reason, two MRM 100s, the lower-end models of the same product line with built-in dial backup modems, are used as backup equipment. Given that MRM 100s are lower-end models, their reliability and internal redundancy features may not be as strong as the higher-end models. For that reason, using not one but two backups with a 1-to-2 cardinality appears to be a sensible risk-management strategy. Of course, this configuration is most effective only in conjunction with an availability software such as VRRP. With some commercial products, VRRP may come as a feature of the standard software. In some others, it may require a special purchase or be part of a special software bundle. In the configuration discussed, we define MRM 5000 as the default router for all the workstations, PCs and laptops in the office, that is, all traffic that cannot be routed directly gets directed to MRM 5000 as long as it is operational. We configure the MRM 100s as two backups of MRM 5000, one with priority 5, the other with priority 250, to avoid any race condition that may occur because of closeness of priorities. MRM 100's dial backup features are also configured for dial-on-demand, so that when the router becomes the master, a trigger event activates the modem to dial into the modem bank of the Corporate Office. Although MRM 100 supports a simple agent that can detect the state change in VRRP and activate the modem when the router becomes the master, we prefer the use of the dial-on-demand feature of the MRM 100 to handle also cases that are not related to VRRP failover situations. With this feature enabled, the presence of the packets in the router destined toward the cloud activates the modem.

MRM 100s have built-in policy agents that can be configured to suppress a specified type of traffic. This is particularly useful to suppress nonessential traffic while the MRM 100s are acting as masters since they are connected over a low-bandwidth dial-up link. For example, when the MRM 5000 fails and MRM 100 takes over as the master, the policy filters could be set up only to pass through essential traffic between corporate network and the home network such as intranet network, database, and firewall server connectivity. It is good practice to program the filters to suppress email and Internet/Web traffic to alleviate the degradation of service after the VRRP switchover.

2.11.2  Load Sharing in the Branch

Some branches of the enterprise network have different networking and availability requirements. Because of their special criticality to the business and their special impact on the bottom line, different budgets are allocated to such organizations. If we were to call the configuration we discuss in Figure 2-14 small branch network, big branch network would be a proper label for the solution depicted in Figure 2-15. This configuration consists of two MRM5005s connected to the cloud through leased lines and mutually backing each other up by establishing two VRRP virtual routers. Since MRM 5005s have built-in DSU/CSU capability, we don't represent this equipment explicitly in Figure 2-15.

Figure 2-15FIGURE 2-15. Load sharing in a branch


In the big branch configuration, we define two virtual routers and assign one MRM 5005s as master to a virtual router respectively. Keeping in mind the large amount of computer equipment in the office, we place intelligent hubs BSM 10 on the LAN. We group the default router assignments accordingly. We assign MRM 5005 on the left as the default for the hosts attached to the BSM 10 on the left, and we designate MRM 5005 on the right as the default router for the hosts attached to the BSM 100 on the right.

When both MRM 5005s are operational, they act as the master of their virtual routers and share the burden of handling the traffic originating from the office network. When one of the MRM 5005s fails, the other becomes the default router for all the hosts in the network. Given the hardware-based forwarding engines of the routers and the relatively higher capacity of the leased lines (T3), we assume that the service degradation should not be noticeable. Given this assumption, we enable the policy agents conditionally to suppress nonessential messages only when the traffic demands a certain level of bandwidth.

Although there might be some concerns about the impact of the BSM 100 devices on availability, given the simplicity of these devices, they have lesser chances of being additional points of failure in the network.

  • + Share This
  • 🔖 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.

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