Home > Articles > Certification > Cisco Certification > CCNP

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

Summary

In this chapter, you learned about implementing path control. The chapter focused on the following topics:

  • Redundant network considerations including resiliency, availability, adaptability, performance, support for network and application services, predictability, and asymmetric traffic.
  • Path control tools including a good addressing design, redistribution and other routing protocol characteristics, passive interfaces, distribute lists, prefix lists, administrative distance, route maps, route tagging, offset lists, Cisco IOS IP SLAs, and PBR. (Advanced tools covered briefly include Cisco IOS OER, virtualization, and Cisco WAAS.)
  • Offset lists, a mechanism for increasing incoming and outgoing metrics to routes learned via EIGRP or RIP. Configuration of offset lists is performed with the offset-list {access-list-number | access-list-name} {in | out} offset [interface-type interface-number] router configuration command. Verification of offset lists can be performed with the traceroute command, the show ip route command, and the show ip eigrp topology command.
  • Cisco IOS IP SLAs, which use active traffic monitoring, generating traffic in a continuous, reliable, and predictable manner, to measure network performance. IOS IP SLAs can be used in conjunction with other tools, including the following:
    • Object tracking, to track the reachability of specified objects
    • Cisco IOS IP SLAs probes, to send different types of probes toward the desired objects
    • Route maps with PBR, to associate the results of the tracking to the routing process
    • Static routes with tracking options, as a simpler alternative to PBR
  • Cisco IOS IP SLAs terminology, including the following:
    • All the Cisco IOS IP SLAs measurement probe operations are configured on the IP SLAs source, either by the CLI or through an SNMP tool that supports IP SLAs operation. The source sends probe packets to the target.
    • There are two types of IP SLAs operations: those in which the target device is running the IP SLAs responder component, and those in which the target device is not running the IP SLAs responder component (such as a web server or IP host).
    • An IP SLAs operation is a measurement that includes protocol, frequency, traps, and thresholds.
  • Configuring IOS IP SLAs, including the use of the following commands:
    • The ip sla operation-number global configuration command (or the ip sla monitor operation-number global configuration command) to begin configuring a Cisco IOS IP SLAs operation and enter IP SLA configuration mode (or rtr configuration mode).
    • The icmp-echo {destination-ip-address | destination-hostname} [source-ip {ip-address | hostname} | source-interface interface-name] IP SLA configuration mode command (or the type echo protocol ipIcmpEcho {destination-ip-address | destination-hostname} [source-ipaddr {ip-address | hostname} | source-interface interface-name] rtr configuration mode command) to configure an IP SLAs ICMP echo operation.
    • The frequency seconds IP SLA configuration submode command (or rtr configuration submode command) to set the rate at which a specified IP SLAs operation repeats.
    • The timeout milliseconds IP SLA configuration submode command (or rtr configuration submode command) to set the amount of time a Cisco IOS IP SLAs operation waits for a response from its request packet.
    • The ip sla schedule operation-number [life {forever | seconds}] [start-time {hh:mm[:ss] [month day | day month] | pending | now | after hh:mm:ss}] [ageout seconds] [recurring] global configuration mode command (or the ip sla monitor schedule operation-number [life {forever | seconds}] [start-time {hh:mm[:ss] [month day | day month] | pending | now | after hh:mm:ss}] [ageout seconds] [recurring] global configuration mode command) to configure the scheduling parameters for a single Cisco IOS IP SLAs operation.
    • The track object-number ip sla operation-number {state | reachability} global configuration command (or the track object-number rtr operation-number {state | reachability} global configuration command) to track the state of an IOS IP SLAs operation, and enter track configuration mode.
    • The delay {up seconds [down seconds] | [up seconds] down seconds} track configuration command to specify a period of time to delay communicating state changes of a tracked object.
    • The ip route prefix mask {ip-address | interface-type interface-number [ip-address]} [dhcp] [distance] [name next-hop-name] [permanent | track number] [tag tag] global configuration command to establish a static route that tracks an object.
  • Verifying Cisco IOS IP SLAs, including the use of the show ip sla configuration [operation] command (or the show ip sla monitor configuration [operation] command), and the show ip sla statistics [operation-number] [details] command (or the show ip sla monitor statistics [operation-number] [details] command).
  • Using PBR to control path selection, providing benefits including source-based transit provider selection, QoS, cost savings, and load sharing. PBR is applied to incoming packets; enabling PBR causes the router to evaluate all packets incoming on the interface using a route map configured for that purpose.
  • Configuring and verifying PBR, including the following steps:
    • Choose the path control tool to use; for PBR, route-map commands are used.
    • Implement the traffic-matching configuration, specifying which traffic will be manipulated; match commands are used within route maps.
    • Define the action for the matched traffic, using set commands within route maps.
    • Optionally, fast-switched PBR or CEF-switched PBR can be enabled. Fast-switched PBR must be enabled manually. CEF-switched PBR is automatically enabled when CEF switching is enabled and PBR is enabled.
    • Apply the route map to incoming traffic or to traffic locally generated on the router.
    • Verify path control results, using show commands.
  • PBR match commands, including the following:
    • The match ip address {access-list-number | name} [...access-list-number | name] route map configuration command
    • The match length min max route map configuration command
  • PBR set commands, including the following four which are evaluated in this order (as soon as a destination address or interface has been chosen, other set commands for changing the destination address or interface are ignored):
    • The set ip next-hop ip-address [...ip-address] route map configuration command, which affects all packet types and is always used if configured.
    • The set interface type number [...type number] route map configuration command. If there is no explicit route for the destination address of the packet in the routing table (for example, if the packet is a broadcast or is destined for an unknown address), the set interface command has no effect and is ignored. A default route in the routing table is not considered an explicit route for an unknown destination address.
    • The set ip default next-hop ip-address [...ip-address] route map configuration command. A packet is routed to the next hop specified by the set ip default next-hop command only if there is no explicit route for the packet's destination address in the routing table. A default route in the routing table is not considered an explicit route for an unknown destination address.
    • The set default interface type number [...type number] route map configuration command. A packet is routed to the next hop specified by the set default interface command only if there is no explicit route for the packet's destination address in the routing table. A default route in the routing table is not considered an explicit route for an unknown destination address.
  • Other PBR set commands, including the following:
    • The set ip tos [number | name] route map configuration command, used to set the 5 CoS bits. Values 0 through 15 are used; one of the bits is reserved.
    • The set ip precedence [number | name] route map configuration command, used to set the 3 IP precedence bits in the IP packet header.
    • The set ip next-hop verify-availability [next-hop-address sequence trackobject] route-map configuration command to configure policy routing to verify the reachability of the next hop of a route map before the router performs policy routing to that next hop.
  • Commands to configure PBR on an interface, including the following:
    • The ip policy route-map map-tag interface configuration command, configured on the interface that receives the packets, not on the interface from which the packets are sent
    • The ip local policy route-map map-tag global configuration command, to apply a route map to packets originating on the router
  • Commands to verify PBR, including the show ip policy command, the show route-map [map-name] command, the debug ip policy command, the traceroute command, and ping command.
  • Advanced path control tools, including the following:
    • Cisco IOS OER, which uses tools such as Cisco IOS IP SLAs to automatically detect network service degradation and to make dynamic routing decisions and adjustments based on criteria such as response time, packet loss, jitter, path availability, traffic load distribution, and so forth
    • Virtualization, such as the use of VRF tables, VLANs, VPNs, and GRE tunnels
    • Cisco WAAS, including the use of WCCP to redirect normal traffic flows into Cisco WAAS devices
  • + 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