Home > Articles > Cisco Certification > CCNP > Shooting Trouble with IP

Shooting Trouble with IP

  • Sample Chapter is provided courtesy of Cisco Press.
  • Date: Jul 11, 2003.

Chapter Description

As more and more companies are adopting IP-based networks, the jobs of network engineers and analysts are becoming more demanding. Learn about IP protocols and packets, addressing, and routing protocol topics to get you started with IP troubleshooting.

Routing Protocols

Routing protocols have their own unique characteristics, and various Layer 2 encapsulation types have a big impact on them. Understanding how they work will certainly assist you in troubleshooting them now and later. Most of the statistics listed for each can be found with IOS commands such as show ip protocols, show ip route, and show ip routing-protocol ?. Logging, debug, and protocol analyzers all with various levels of impact on the working environment are certainly valuable tools to see more detail when troubleshooting, too. However, I want you to reserve them for later chapters. After all, many of these protocols are not just IP-specific.

First I discuss the following Interior Gateway Protocols (IGPs): RIP, Interior Gateway Routing Protocol (IGRP)/Enhanced Interior Gateway Routing Protocol (EIGRP), OSPF, and IS-IS. Then I review Border Gateway Protocol (BGP), which is an Exterior Gateway Protocol (EGP).


Routing Information Protocol (RIP) was originally designed for Xerox PARC Universal Protocol (PUP), and in many ways is still for "pups." It was called GWINFO in the Xerox Network Systems (XNS) protocol suite in 1981, and defined in RFC 1058 in 1988. It is easy to configure, and it works very well in small networks. In larger networks, however, it can be less effective; as I say to myself, "It can RIP you apart." There are alternatives to RIP for larger environments.

Everyone knows RIP because it has been widely adopted by PC, UNIX, and router makers alike. RIP has disadvantages in that it operates over UDP port 520 and the maximum hop count is 15. RIPv2 assists with the broadcast nature in that it operates via multicast over Both RIPv1 and RIPv2 are distance vector routing protocols, which are often referred to as routing by rumor protocols.

Examine the following list of RIP characteristics and refer back to the examples throughout the chapter, for you have already experimented with RIPv1 and RIPv2. I hope your practical exercises, with RIPv1 not supporting discontiguous subnets and RIPv2 supporting them, will stay with you for a long time.

The following are RIP characteristics:

  • Open protocol, widely used, stable.

  • Good for small networks in that it is very easy to configure.

  • There are RIP-like distance vector routing protocols for Novell and AppleTalk.

  • Distance vector routing protocol.

  • IGP.

  • IP RIP updates are sent every 30 seconds via broadcast ( for RIPv2).

  • UDP port 520

  • Administrative distance is 120.

  • Single metric is hop count. (The limit is 15 to assist with count-to-infinity.)

  • Timers help regulate performance:

    • Update timer—Frequency of routing updates. Every 30 seconds IP RIP sends a complete copy of its routing table, subject to split horizon. (IPX RIP does this every 60 seconds.)

    • Invalid timer—Absence of refreshed content in a routing update. RIP waits 180 seconds to mark a route as invalid and immediately puts it into holddown.

    • Hold-down timers and triggered updates—Assist with stability of routes in the Cisco environment. Holddowns ensure that regular update messages do not inappropriately cause a routing loop. The router doesn't act on nonsuperior new information for a certain period of time. RIP's hold-down time is 180 seconds.

    • Flush timer—RIP waits an additional 240 seconds after holddown before it actually removes the route from the table.

  • Other stability features to assist with routing loops include the following:

    • Split horizon—Not useful to send information about a route back in the direction from which it came.

    • Poison reverse—Updates that are sent to invalidate a route and place it in holddown.

  • Bellman-Ford algorithm.

  • RIPv2 supports VLSM and summarization. (RIPv1 doesn't.) RIPv2 always autosummarizes at the class boundary.

RIP maintains only the best route in its routing table, as you can verify in examples throughout the chapter. In Example 3-2, for example, I configured RIPv1 on r1 and continued to configure the other routers. In Example 3-15, while troubleshooting I looked at the routing tables and IP routing protocols. Then I configured RIPv2 in Example 3-21. Example 3-22 displays the routing tables and output of show ip protocols with RIPv2 configured. Look back at these examples to review such things as the update characteristics, timers, and administrative distance associated with RIP.

Example 3-35 illustrates routes in holddown. First I turn on service time stamps and set the clock so that you can see the actual timing of events. Then I turn on debug ip rip events, remove the cable from router 2 Serial 1, plug it back in, watch the routing updates, and view the appropriate routing tables.


As always, in a practical environment be very careful with running debug commands due to their excessive memory requirements and stressful nature on the devices. Notice my in-line comments where I unplugged and plugged the cable back in.

Example 3-35 Debug Output for RIPv2 Packets

r1(config)#service timestamps debug datetime localtime
r1#clock set 3:22:00 11 October 2002
r1#copy running-config startup-config
Destination filename [startup-config]? 
Building configuration...
r1#debug ip rip events
RIP event debugging is on
Oct 11 03:22:52: RIP: sending v2 update to via Ethernet0 (
Oct 11 03:22:52: RIP: Update contains 8 routes
Oct 11 03:22:52: RIP: Update queued
Oct 11 03:22:52: RIP: sending v2 update to via Ethernet1 (
Oct 11 03:22:52: RIP: Update sent via Ethernet0
Oct 11 03:22:52: RIP: Update contains 5 routes
Oct 11 03:22:52: RIP: Update queued
Oct 11 03:22:52: RIP: sending v2 update to via Serial0 (
Oct 11 03:22:52: RIP: Update sent via Ethernet1
Oct 11 03:22:52: RIP: Update contains 8 routes!
Oct 11 03:22:52: RIP: Update queued
Oct 11 03:22:52: RIP: sending v2 update to via Serial1 (
Oct 11 03:22:52: RIP: Update sent via Serial0
Oct 11 03:22:52: RIP: Update contains 4 routes
Oct 11 03:22:52: RIP: Update queued
Oct 11 03:22:52: RIP: Update sent via Serial1
Oct 11 03:22:59: RIP: received v2 update from on Serial1
Oct 11 03:22:59: RIP: Update contains 5 routes
Oct 11 03:23:02: RIP: received v2 update from on Ethernet1
Oct 11 03:23:02: RIP: Update contains 4 routes
r1#!!!now I will unplug the r2s1 cable
Oct 11 03:23:14: RIP: received v2 update from on Serial1
Oct 11 03:23:14: RIP: Update contains 5 routes
Oct 11 03:23:14: RIP: received v2 update from on Ethernet1
Oct 11 03:23:14: RIP: Update contains 4 routes
Oct 11 03:23:14: RIP: sending v2 update to via Ethernet0 (
Oct 11 03:23:14: RIP: Update contains 8 routes
Oct 11 03:23:14: RIP: Update queued
r1#show ip route
C is directly connected, Ethernet1
R is possibly down, routing via, Ethernet1 is variably subnetted, 3 subnets, 2 masks
R [120/1] via, 00:00:10, Serial1
R [120/2] via, 00:00:07, Ethernet1
C is directly connected, Serial0
R [120/1] via, 00:00:07, Ethernet1
          [120/1] via, 00:00:11, Serial1
C is directly connected, Ethernet0
C is directly connected, Serial1
R [120/1] via, 00:00:11, Serial1

Plug the cable back in, continue to review the results, and turn off all debug activity, as in Example 3-36.

Example 3-36 Plug the Cable Back In and Observe the Results

r1#!!!now I will plug the cable back in
r1#show ip route
C is directly connected, Ethernet1
R is possibly down, routing via, Ethernet1 is variably subnetted, 3 subnets, 2 masks
R [120/1] via, 00:00:13, Serial1
Oct 11 03:26:16: RIP: received v2 update from on Ethernet1
Oct 11 03:26:16: RIP: Update contains 4 routes
Oct 11 03:26:16: RIP: sending v2 update to via Ethernet0 (
Oct 11 03:26:16: RIP: Update contains 8 routes
Oct 11 03:26:16: RIP: Update queued
Oct 11 03:26:16: RIP: sending v2 update to via Ethernet1 (
Oct 11 03:26:16: RIP: Update sent via Ethernet0
Oct 11 03:26:16: RIP: Update contains 5 routes
Oct 11 03:26:16: RIP: Update queued
r1#show ip route
C is directly connected, Ethernet1
R [120/1] via, 00:00:04, Ethernet1 is variably subnetted, 3 subnets, 2 masks
R [120/1] via, 00:00:07, Serial1
R [120/2] via, 00:00:04, Ethernet1
C is directly connected, Serial0
R [120/1] via, 00:00:04, Ethernet1
          [120/1] via, 00:00:07, Serial1
C is directly connected, Ethernet0
C is directly connected, Serial1
R [120/1] via, 00:00:07, Serial1
r1#undebug all

Fix any issues before you continue. If you cannot see the debug output when you telnet in, you may need to turn on terminal monitor (term mon). In this example, I did not show the output of the interface status on r2, but that is pretty important in troubleshooting such issues. Repeat the example as necessary or log it for future reference.

See Figure 3-24 or look at one of your Sniffer traces to analyze the RIP packet format. Up to 25 destinations can be listed in a single packet. Next I discuss the Cisco proprietary routing protocols IGRP and EIGRP.


Interior Gateway Routing Protocol (IGRP) was developed in the mid-1980s as a Cisco proprietary protocol to help overcome some of limitations of RIP, such as the single metric of hop count. It has stability features similar to RIP—hold-down timers, split horizon, poison reverse, and triggered updates. The timers are as follows: invalid 270 seconds, holddown 280 seconds, and flush 630 seconds. It also contains mechanisms to influence route selection and unequal load sharing. I use the phrase Big Dogs Really Like Meat to remember the metrics for IGRP and EIGRP:

  • Bandwidth

  • Delay

  • Reliability

  • Load

  • MTU

IGRP is an IGP, a distance vector routing protocol based on the Bellman-Ford algorithm that broadcasts routing updates every 90 seconds over IP protocol number 9. It is fine for small and medium-size networks, but Cisco enhanced it greatly and added VLSM support to its replacement, EIGRP.

Cisco developed Enhanced IGRP (EIGRP) in the early 1990s to overcome limitations of RIP and its own IGRP. Cisco says IGRP is going to be removed from IOS. EIGRP is suitable for large networks today and supports multiple routed protocols. It consumes significantly less bandwidth because of its partial, bounded updates, and can be one of the fastest converging routing protocols there is.

The following are EIGRP characteristics:

  • Cisco proprietary protocol.

  • Good for small to large networks.

  • Very easy to configure. Uses autonomous system (AS) number.

  • Supports multiple Layer 3 routed protocol stacks, such as IP, Novell IPX, and AppleTalk.

  • Advanced distance vector routing protocol. Often called a hybrid due to its incremental updates and rapid convergence capabilities.

  • IGP.

  • Multicast triggered updates over, not periodic.

  • IP protocol number 88.

  • Internal administrative distance is 90; external is 170.

  • Metrics are bandwidth, delay, reliability, load, and MTU.

  • Supports equal- and unequal-cost load sharing.

  • Other stability features to assist with routing loops:

    • Split horizon—Not useful to send information about a route back in the direction from which it came

    • Poison reverse—Updates that are sent to remove a route and place it in holddown

  • Uses Diffusing Update algorithm (DUAL) to select loop-free paths and give it very fast convergence.

  • Supports VLSM and manual summarization (classless).

  • Automatic classful boundary summarization.

  • Manual summarization on update sent out each interface.

  • Automatic redistribution with IGRP if same AS number.

  • Route tagging for policy-based routing.

EIGRP gets its reliability from the Reliable Transport Protocol (RTP). It maintains not only a routing table, but also a neighbor and topology table. EIGRP maintains alternate routes referred to as successors (routing table) and feasible successors (topology table) to quickly converge. The following packet types are used for neighbor communications: hellos (multicast) and acks (unicast), update (multicast or unicast), query (multicast), reply (unicast), and request (multicast or unicast). Packets are held in a queue for retransmission, and there are separate neighbor tables (and entirely separate processes) for each protocol.

Cisco has some wonderful white papers on EIGRP that you should download and review to assist you with troubleshooting. Other popular references include the book EIGRP Network Design Solutions (Cisco Press). Just remember when troubleshooting EIGRP, active ain't good, but passive is. Active means that you are actively looking for something that you don't have. Pay particular attention to summarization when you are experiencing stuck-in-active situations. Besides the basic IOS commands in your repertoire, you should add show ip eigrp ? and debug ip eigrp ? for your EIGRP IP troubleshooting assistance. Next I very briefly review OSPF, IS-IS, and BGP. You will continue to configure, analyze, and troubleshoot the convergence of these protocols over various Layer 2 technologies throughout the rest of this book.


Open Shortest Path First (OSPF) overcomes the disadvantages of RIP and is not proprietary in nature, but its openness supports only the IP routed protocol. The protocol is a link-state IGP based on the Dijkstra algorithm developed by the Internet Engineering Task Force (IETF) to support large heterogeneous networks. Lots of research was completed from 1987 until the current OSPFv2 specification in 1991. Link-state advertisements are sent to all, which causes an initial flood on the router; after that, however, OSPF is very efficient in operation. It uses three different databases (tables) for the neighbors, link states, and routes.

The following are OSPF characteristics:

  • Open protocol.

  • Good for small to large networks.

  • Not as easy to design and configure as other protocols.

  • Supports only the IP Layer 3 routed protocol stack.

  • Link-state routing protocol (doesn't just send to neighbors like distance vector).

  • IGP.

  • Multicast link-state advertisement (LSA) updates over and

  • IP protocol number 89.

  • Administrative distance is 110.

  • Metric is a cumulative cost (inversely proportional to bandwidth).

  • Supports only equal-cost load sharing, but some implementations can take advantage of type of service (TOS) requests.

  • Requires a routing hierarchy in that every area must touch the backbone area (otherwise temporary fixes such as virtual links are used). Various router types, LSA types, area types, and states, depending on your design and Layer 2 topology.

  • Uses Dijkstra algorithm to select loop-free paths and give it fast convergence. This uses LSAs and is based on the Shortest Path First (SPF) algorithm, where the protocol got its name.

  • Supports VLSM and summarization (classless).

  • Supports manual summarization only; this is not automatic like EIGRP. Must be performed on an ABR (area range) or ASBR (summary address) only.

  • Route tagging for policy-based routing.

Besides the basic IOS commands in your repertoire, you should add show ip ospf ? and debug ip ospf ? for your OSPF troubleshooting assistance.

OSPF references include the books OSPF Network Design Solutions (Cisco Press) and OSPF: Anatomy of an Internet Routing Protocol (Addison-Wesley). John Moy is the author of the latter, and if you truly want the RFC detail, this is the book to read. Next take a look at IS-IS.


The ISO was working on Intermediate System-to-Intermediate System (IS-IS) about the same time the IAB was working on OSPF. The late 1980s and early 1990s, a time in our history when everyone thought the OSI suite would overtake TCP/IP, was when Integrated IS-IS was proposed. Although originally designed for OSI routing, IS-IS was developed by ISO to support CLNS/CLNP. Integrated IS-IS, which supports IP, was a later development. The purpose was to provide a single routing protocol that could route Connectionless Network Protocol (CLNS) and IP. IS-IS is in use by ISPs today. OSPF and IS-IS have many common features.

The following are IS-IS characteristics:

  • Open protocol.

  • Good for medium to very large networks.

  • ISO link-state routing protocol similar to OSPF.

  • IGP.

  • IS-IS Layer 2 PDUs rather than IP packets.

  • Uses Layer 2 multicast.

  • Administrative distance is 115.

  • Very limited metric dynamic range (0–63).

  • Equal-cost load sharing.

  • Two-level hierarchical topology.

  • Uses Dijkstra/SPF algorithm.

  • Supports VLSM and summarization.

  • Manual summarization.

  • Route tagging for policy-based routing.

Besides the basic IOS commands in your repertoire, you should add show is-is ?, show clns ?, and debug is-is ? for your IS-IS troubleshooting assistance.

Jeff Doyle's Routing TCP/IP, Volume I does a good job of explaining many topics, including IS-IS. Volume II is great for BGP, as is Sam Halabi's Internet Routing Architectures.


Border Gateway Protocol (BGP) is an EGP that pretty much replaces the legacy EGP protocol itself. BGP performs routing between autonomous systems and is the standard routing protocol on the Internet. This is referred to as External BGP (EBGP), whereas when BGP is used to route within an AS it is referred to as Interior (IBGP). BGP is not a routing protocol for the fainthearted. It requires all manual configurations for a very good reason; you are not only affecting you, but you are also affecting me. For troubleshooting BGP, if routes are not in the BGP table, there is no way they will be in the routing table. Always make sure your neighbors are talking to you. One of the most useful commands in troubleshooting BGP is show ip bgp summary.

The following are BGP characteristics:

  • Open protocol.

  • Good for very large internetworks.

  • Not as easy to design and configure as other protocols. Everything is manual, including neighbors (peers).

  • Advanced distance vector or path vector routing protocol.

  • EGP.

  • TCP port 179.

  • Internal administrative distance is 200; external is 20.

  • Metrics include many attributes such as MED, Origin, AS-Path, Next-hop, and Community.

  • Does not demand a particular routing hierarchy; roll your own.

  • Automatic and manual summarization features.

  • Route tagging for policy-based routing.

Besides the basic IOS commands in your repertoire, you should add show ip bgp ? and debug ip bgp ? for your BGP troubleshooting assistance. Remember that BGP is an EGP and that what you do affects others. ISPs often turn on dampening to account for those who really don't know what they are doing with BGP configuration or to compensate for link flaps. Too many changes within a certain period of time may mean that you don't get to communicate at all.

Individual routing protocols are books in themselves. However, I have quickly summarized the common routing protocols for you. The routing table is a good place to start troubleshooting, but if routes are missing, ultimately they may depend on Physical Layer or Data Link Layer issues, neighbor relationships, and topology or link-state tables. Cisco does a great job at categorizing more specific IP routing issues for you (see Figure 3-33).

Figure 33Figure 3-33 IP Routing Top Issues


Refer back to Chapter 1, Table 1-3, for a quick comparison of routing protocols.

Now it is time for the Trouble Tickets. The plan here is to give you several things to do, let you make mistakes and fix some things on your own, and to introduce other problems that you should have some experience with as a support person. Shooting trouble with IP can easily be a multiple-volume set of books in itself. Because it is a big part of troubleshooting today, I also integrate more IP-related issues into the other chapters.


Do not write erase your routers and start from scratch. Whether it is now or later, you will learn from your own mistakes. In the real world, many times I find it easier to just start from scratch if things differ that much. In many cases, you do not have that luxury—for what you change on a router affects not just one person, but many others, and change control is a definite must.

5. Trouble Tickets | Next Section Previous Section

Cisco Press Promotional Mailings & Special Offers

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


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about Cisco Press 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.


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.


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


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


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


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.


Users can always make an informed choice as to whether they should proceed with certain services offered by Cisco Press. 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.ciscopress.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.


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