Dennis caught our eye creating Visio versions of the best-selling Volume 1 workbook network topology for his fellow students in the IEOC. Thanks again Dennis and enjoy your $50 Gift Certificate for Amazon.com.

The files that Dennis created for his fellow students can be found by clicking here.

Here is his story...

In 1991, I began my official work life as a Customer Service Representative.  I repaired all manner of equipment for many well-known small to medium sized retail chains and large retail chains with names ending in "mart".  In 1996 I took a position with a small contracting company working at NOAA (National Oceanic and Atmospheric Administration).  I worked as a Help desk Engineer for several years.  I became Microsoft MSCE certified in 1998.  In 1999 I took another position within my company still at NOAA for their Computer Incident Response Team.  I had several satisfying years in that position learning all about incident detection, response and remediation.

I always eventually felt I would like to get Cisco certified.  In 2003, I was fortunate to take some time off to devote to making a career shift into the networking field.  I spent several months taking classes from another now defunct Cisco Authorized training Center.  I became CCNP Certified in 2004.  Fortune was with me again, as in 2004  was able to take a position back with the same small contracting company for a position back at NOAA.  It was an exciting position to re-design the primary network for the NWS Telecommunications Gateway.  I am still working their today support the network I helped design.  A large portion of weather data provided by the National Weather Service transits the very network I support.  It is a pleasure to know that the network I support helps save lives on a daily basis.

I bought my Self-Paced R&S End-to-End CCIE Training Program back in 2006 from INE.  I was not able to devote the time I wanted to studying for the first few years.  My time was devoted to wife and our three new wonderful children. I even inadvertently let my CCNP certification expire.   I must have been deliriously tired from the kids not to get that done before it expired.   I got back to seriously studying for the CCIE in early 2010.  My company asked me to take a break recently from CCIE studies to re-certify CCNP.  How fortunate for all the Christmas deals from INE.  I passed my CCNA and CCNA Security in early January thanks to the most excellent boot camps by Brian along with the Official Exam Certification Guides.  I am finding the whole process to be easier than the first time in 2004 when I was pretty new to the whole thing.  I just reviewed the self-paced versions of the CCNP, IPV6 and BGP Bootcamps.  Along with the Route Official Certification Exam Guide, they were invaluable for my attempt at the 642-902 ROUTE Exam. I am happy to say that I  just passed it this very January 29^th.  Only SWITCH and TSHOOT left for CCNP re-certification.  No sense wasting the invaluable time spent on the  BGP Bootcamp; I plan on going for the CCIP also before returning to my CCIE R&S studies.  When I finally return to the CCIE R&S studies, I will be going back to my schedule I laid out using Petr Lapukhov’s blog:  Getting the most out of CCIE R&S Workbooks VOL1 and VOL2 One word, AMAZING! It provided me a detailed map for my CCIE journey I was lacking.  All right, end of commercial.  The staff at INE are great.

I enjoy trying to help out and to learn on IEOC when I have the time, between work and my wonderful family.  It is a great venue to interact and learn with knowledgeable and helpful individuals.  I hope to someday reach the Elite status of some more worthy unrecognized individuals.  I don’t know when I will reach my CCIE goal, but it is a rewarding journey.

Many times, students believe that they could use a bit of a boost when it comes to solving the very complex and difficult Practice Lab Exams featured in our famous Volume II workbook here at INE. To respond to this, Keith Barker and I came up with an idea for a new INE product unlike anything that had been created before.

We created a fully interactive video guide to lab exam strategy and actual solutions for the first five labs of the workbook. But we did not stop there. We also recorded bonus lessons on topic areas that students always seem to want extra guidance with. Such areas as:

• Am I fast enough when it comes to making configurations?
• What is the best way to master DOC-CD navigation?
• What are appropriate strategies for Troubleshooting?
• What should I do if I am struggling with Redistribution tasks?

Here are some sample lessons from the Interactive Video Companion for Volume II so you can see this remarkable product for yourself. I am also publishing the complete outline here so you can examine that as well.

Samples:

Lab 1 - Layer 2 Private VLANs

Version 4 Challenge - Speed Drill

Version 4 Challenge – MPLS L3 VPN Troubleshooting

The Course Outline:

Lab 1 - Dos and Donts - 20 minutes
Lab 1 - Lab Strategy - 30 minutes
Lab 1 - Backup Link - 20 minutes
Lab 1 - Spanning Tree Manipulation - 10 minutes
Lab 1 - Spanning Tree Security - 15 minutes
Lab 1 - Private VLANs - 30 minutes
Lab 1 - Layer 2 Traffic Engineering - 20 minutes
Lab 1 - OSPF Prefix Adv - 10 minutes

Lab 1 - OSPF Broadcast-Nonbroadcast - 30 minutes
Lab 1 - Version 4 Challenge - Speed Drill - 30 minutes
Lab 1 - EIGRP Advertisements - 12 minutes
Lab 1 - EIGRP Authentication - 5 minutes
Lab 1 - RIP Authentication - 10 minutes
Lab 1 – Redistribution - 30 minutes
Lab 1 - BGP Bestpath Selection - 20 minutes
Lab 1 - IPv6 Addressing - 10 minutes
Lab 1 - IPv6 Tunneling - 10 minutes
Lab 1 - EIGRPv6 - 10 minutes
Lab 1 - IPv6 Multicast - 15 minutes
Lab 1 – LDP - 12 minutes
Lab 1 - L3 MPLS VPN - 20 minutes
Lab 1 - RP Assignment - 15 minutes
Lab 1 - Multicast Testing - 20 minutes
Lab 1 - ip igmp access-group - 10 minutes
Lab 1 - Ext ACL TCP Flags - 12 minutes
Lab 1 - Filtering with ACLs - 20 minutes
Lab 1 - Controlling ICMP - 20 minutes
Lab 1 - Adv ACL Features – TTL - 20 minutes
Lab 1 – RMON - 25 minutes
Lab 1 – NTP - 20 minutes
Lab 1 - NTP Authentication - 25 minutes
Lab 1 - IP Accounting - 10 minutes
Lab 1 – HSRP - 25 minutes
Lab 1 – NAT - 12 minutes
Lab 1 – EEM - 18 minutes
Lab 1 – FRTS - 25 minutes
Lab 1 - Version 4 Challenge – Troubleshooting - 10 minutes
Lab 1 - Rate Limiting - 10 minutes
Lab 1 – CBWFQ - 20 minutes
Lab 1 - Cat QoS - 15 minutes
Lab 4 - Traffic Control (VTP Pruning) - 15 minutes
Lab 4  - STP Manipulation - 16 minutes
Lab 4 – UDLD - 15 minutes
Lab 4 - STP Path Manipulation 2 - 10 minutes
Lab 4 - Storm Control - 10 minutes
Lab 4 - Version 4 Challenge - DOC-CD Speed Drill - 10 minutes
Lab 4 - IP Prec to DSCP Map - 10 minutes
Lab 4 - Version 4 Challenge - Speed Drill - 40 minutes
Lab 4 - Version 4 Challenge - MPLS L3 VPN TS - 60 minutes
Lab 4 - QoS Trust Boundaries - 10 minutes
Lab 4 - Virtual Link Alternatives - 10 minutes
Lab 4 - OSPF Area Types - 20 minutes
Lab 4 - OSPF Version 3 - 20 minutes
Lab 4 - OSPFv3 Summarization - 10 minutes
Lab 4 - PE-CE Routing – RIP - 10 minutes
Lab 4 - VPN Tunneling - 20 minutes
Lab 4 - PE-CE Routing – BGP - 15 minutes
Lab 4 - Auto RP - 25 minutes
Lab 4 - Multicast Testing - 30 minutes
Lab 4 - Multicast Rate Limiting - 10 minutes
Lab 4 - Zone Based Firewall - 30 minutes
Lab 4 - Unicast RPF - 15 minutes
Lab 4 - Control Plane Policing - 15 minutes
Version 4 Challenge - DOC-CD Speed Drill 2 - 5 minutes
Lab 4 – SNMP - 10 minutes
Lab 4 - IOS Menu - 10 minutes
Lab 4 - ip alias Command - 10 minutes
Lab 4 - Load Balancing HSRP - 10 minutes
Lab 4 - busy-message Command - 10 minutes
Lab 4 – WRED - 10 minutes
Lab 4 - CBWFQ with NBAR - 10 minutes
Lab 4 - Traffic Policing - 10 minutes
Lab 4 – Compression - 30 minutes
Version 4 Challenge – Layer  3 Speed Drill - 30 minutes
Version 4 Challenge - Troubleshooting Redistribution - 60 minutes
Lab 2 – EtherChannel - 25 minutes
Lab 2 - 802.1X - 30 minutes
Lab 2 – SDM - 15 minutes
Lab 1 - Troubleshooting - Trouble Tickets 1 Thru 5  - 50 minutes
Lab 1 - Troubleshooting - Trouble Tickets 6 through 10 - 50 minutes
Lab 2 - Troubleshooting - Tickets 1 – 5 - 45 minutes
Lab 2 - Troubleshooting - Tickets 6 – 10 - 45 minutes
Lab 2 - OSPF Network Types and OSPF Authentication - 30 minutes
Lab 2 - EIGRP Features - 20 minutes
Lab 2 - RIP Filtering - 20 minutes
Lab 2 - IGP Redistribution - 20 minutes
Lab 2 - BGP Peering - 15 minutes
Lab 2 - BGP Filtering - 20 minutes
Lab 2 - BGP Summarization - 20 minutes
Lab 2 - BGP Tuning - 5 minutes
Lab 2 - IPv6 and Frame Relay - 20 minutes
Lab 2 - L2 MPLS VPNs - 10 minutes
Lab 2 - Static RP - 20 minutes
Lab 2 - PIM NBMA Mode - 10 minutes
Lab 2 - Router Hardening - 10 minutes
Lab 2 - Zone-Based Firewall - 20 minutes
Lab 2 - SNMP Version 2 - 10 minutes
Lab 2 - Reflexive Access Lists - 10 minutes
Lab 2 – RMON - 10 minutes
Lab 2 - Terminal Line Settings - 10 minutes
Lab 2 - IOS Password Encryption - 10 minutes
Lab 2 – Syslog - 10 minutes
Lab 2 - System Management - 10 minutes
Lab 2 – CBWFQ - 10 minutes
Lab 2 - Policy Routing - 10 minutes
Lab 2 – FRTS - 10 minutes
Lab 2 - Congestion Management - 10 minutes
Lab 3 - Troubleshooting - Tickets 1-5 - 45 minutes
Lab 3 - Troubleshooting - Tickets 6-10 - 45 minutes
Lab 3 - Integrated Routing and Bridging - 20 minutes
Lab 3 - L2 Path Manipulation-STP - 20 minutes
Lab 3 - OSPF Features and Redistribution - 40 minutes
Lab 3 - OSPF Virtual Links - 30 minutes
Lab 3 - BGP Path Manipulation - 30 minutes
Lab 3 - BGP Advertise Maps - 30 minutes
Lab 3 - IPv6 Addressing and Tunnels - 15 minutes
Lab 3 - OSPFv3 - 10 minutes
Lab 3 - MPLS Fundamentals - 10 minutes
Lab 3 - Creating VRFs - 30 minutes
Lab 3 -  PE to CE Routing OSPF - 30 minutes
Lab 3 - Muticast IGMP - 10 minutes
Lab 3 - IGMP Multicast Filtering - 5 minutes
Lab 3 - Multicast TTL-Threshold - 10 minutes
Lab 3 -  Reflexive Access Lists - 15 minutes
Lab 3 - TCP Intercept - 10 minutes
Lab 3 - DHCP Server - 30 minutes
Lab 3 - HTTP Access Control - 10 minutes
Lab 3 - IOS TFTP Server - 10 minutes
Lab 3 - Auto-Install - 15 minutes
Lab 3 - Command Privilege Levels - 15 minutes
Lab 3 - Debug at Privilege Level 1 - 10 minutes
Lab 3 - SNMP on Catalyst - 10 minutes
Lab 3 – GLBP - 20 minutes
Lab 3 - Frame Relay Traffic Shaping - 15 minutes
Lab 3 - MQC Policing - 20 minutes
Lab 3 – RSVP - 20 minutes
Lab 4 - Troubleshooting - Tickets 1-5 - 50 minutes
Lab 4 - Troubleshooting - Tickets 6-10 Part 1 - 45 minutes
Lab 4 - Troubleshooting - Tickets 6-10 Part 2 - 45 minutes
Lab 5 - L2 EtherChannel - 15 minutes
Lab 5 - Port-Channel Load Balancing - 15 minutes
Lab 5 - IGP Configuration - 35 minutes
Lab 5 – Redistribution - 35 minutes
Lab 5 - BGP Features - 35 minutes
Lab 5 - IPv6 Frame Mappings - 25 minutes
Lab 5 - IPv6 BGP Features - 15 minutes
Lab 5 - AutoRP Configuration - 25 minutes
Lab 5 - Multicast Features - 25 minutes
Lab 5 - Reflexive Access-lists - 15 minutes
Lab 5 - VLAN ACLs - 25 minutes
Lab 5 - Policy Based Routing - 25 minutes
Lab 5 – SNMP - 10 minutes
Lab 5 - Syslog Server - 10 minutes
Lab 5 – DNS - 10 minutes
Lab 5 - Privilege Levels - 12 minutes
Lab 5 – WCCP - 15 minutes
Lab 5 – EEM - 12 minutes
Lab 5 - MQC QoS - 10 minutes
Lab 5 - RTP Header Compression - 10 minutes
Lab 5 - MQC Bandwidth Limiting - 12 minutes
Lab 5 - Catalyst Nested QoS - 12 minutes
Lab 5 - Troubleshooting - Tickets 1-5 - 45 minutes
Lab 5 - Troubleshooting - Tickets 6-10 - 50 minutes

If you have spent any time in the R&S forums in the IEOC, you have seen the username Deepak Arora. Deepak has achieved Elite status in the forum and is always challenging and helping his peers with his excellent posts.

Thank you so much Deepak, and we look forward to celebrating your number soon. We are placing 100 GradedLabs rack rental tokens in your account as a small gesture of our appreciation.

I am sure many are interested in Deepak's story...here it is:

I started my career in mid 2003 as a System Support Engineer after passing my 3 Year regular Diploma in Electronics (Microprocessor). During the last semester of my study in college I got this opportunity in a campus interview session. Could you believe I was just a 19 year old kid at that point with no idea how things worked in the real world ?...hehe

In 2005, I came to know about CCNA from a pretty close friend, Sushail Sharda, who suggested to me to move into the Networking Industry. I cannot thank him enough for his suggestion because that suggestion changed my life. So finally I started saving money for my CCNA exam and around June 2005 I started preparing for the CCNA exam. By the end of 2005, I passed the exam with a good score. Though it was not an easy one because it was not easy to find training classes and stuff. Of course, INE's CCNA COD and workbooks were not around at that point in time :-)

A few months after passing my CCNA, I moved to another company where I started working as a L1 support engineer and also as a part time CCNA instructor. So after getting quite a bit of experience I decided to go for CCNP. But there were a few major constraints like working on my Graduation through distance learning in parallel to my job and also finding time and equipment to prepare for CCNP. As the time passed by I was able to pass the CCNP BSCI and BCMSN exams. But ONT and ISCW looked always kind of hard for me to pass. But after over a year of hard work,  I finally got my CCNP. After that, the list of certification exams I passed keeps on growing with no stop till now.

It was the beginning of this year when I thought it's time to go for CCIE seriously.  I was thinking about it for quite some time. So I started buying INE R&S products in chunks. Soon I realized that I made my investments on the right material. I spent tons of time watching INE ATC from Brian and I must say the guy is a genius. On the other side there were so many interesting posts on blueprint topics at INE blog which really helped for a better understanding about how things work. Cannot give thanks enough to the entire INE team for such excellent content. Also I found so many bright people at the IEOC support forum like Darrell Escole , Jakub, Able etc ...they were/are helpful and some became close friends later :-)

Finally, I am going to attempt the lab in the end of April. No matter if I pass or fail in my attempt, but I know the INE stuff and all the hard work I put so far in this made me a better Engineer. Sooner or later I know I'll get my Number.

Finally... I hope to pass my lab and after getting my number I'll see if I can work for INE :-) .. hehe ... Every week I still check requirement for R&S Technical Development Engineer job requirement they list on the INE website.

Cisco originally promised us a new CCDP exam (version 2.1) on Nov 8, 2010.

That date is now moved to December 23, 2010. Our Class On Demand was designed to cover you for the old blueprint and the new, so there should be no concern for students. Of course we will be taking the new exam the week following its release and we will be sure to provide any updates to the course that may be required free of charge.

In the meantime, watch blog.ine.com for many posts regarding valuable extra technical information regarding this popular new course. I also want to send out one more thank you to the many students we had that were active participants in the live event. It was an honor to have so many Cisco employees join us, as well as the many highly motivated students from around the world.

We have some exciting free vSeminars on the way. More details will follow, but I wanted everyone to mark the dates now. These events will be recorded and added to:

http://www.ine.com/free-ccie-vseminar.htm

Routing and Switching

October 15, 2010 - Developing Tier 2 Knowledge

November 10, 2010 - “I CANNOT REACH THE BACKBONE!”

Voice

October 22, 2010 - Unified Mobility Interactions with Local Route Group and Globalization

December 14, 2010 - LDAP Synchronization and Authentication in Unified Communications

October 20-22, 2010. Book your seat now! Click here!

Cannot make those dates, purchase now and receive the on-demand version the week following the live event.

Module 1 IPv6 Addressing and Basic Connectivity

• Address Types
• IPv6 Neighbor Discovery
• Basic Connectivity

Module 2 IPv6 Protocols

• IPv6 ICMP
• DHCP for IPv6
• IPSec in IPv6
• QoS for IPv6

Module 3 Static Routing and RIPng

• Static Routing
• Basic RIPng Configuration
• Customizing RIPng

Module 4 OSPF Version 3

• Basic Configuration
• Network Types
• Multiarea Configurations
• Graceful Restart

Module 5 EIGRP for IPv6

• Basic Configuration
• Customizing EIGRP for IPv6

Module 6 Multi-protocol BGP

• Basic Configuration
• Customizing Multi-protocol BGP

Module 7 Filtering and Route Redistribution

• IPv6 Traffic Filtering
• IPv6 Route Update Filtering
• IPv6 Policy Based Routing
• IPv6 Route Redistribution

Module 8 IPv6 Transition Techniques

• Manual Tunnels
• GRE IPv6 Tunnels
• 6to4 Tunnels
• IPv4-Compatible IPv6 Tunnels
• ISATAP Tunnels
• NAT-PT

For success designing and implementing Cisco Wireless solutions, a CCNA Wireless student needs to be familiar with the options for various wireless topologies. Two were defined by the 802.11 committees, while others were made possible thanks to excellent developments by wireless vendors like Cisco Systems.

The 802.11 Topologies

Ad Hoc Mode

While not popular, it is possible to have wireless devices communicate directly with no central device managing the communications. This is called the Ad Hoc network topology and is one of the two topologies defined by the 802.11 committees. In the Ad Hoc type topology, one device sets a group name and radio parameters, and another device uses this information to connect to the wireless network.

This type of wireless network topology is referred to as an Independent Basic Service Set (IBSS). This is easy to remember as we know the devices are working independently of an access point (AP).

Network Infrastructure Mode

When an access point is used to create the network, the official term is network infrastructure mode for the network. There is a Basic Service Set (BSS) setup that uses a single access point, or the Extended Service Set (ESS) that uses multiple access points in order to extend the reach of the wireless network.

Access points running in the network infrastructure mode are often described as a cross between hubs and bridges. The APs act like hubs in that they service a single collision domain and must operate in a half duplex fashion. Fortunately for the AP, it does possess intelligence beyond a simple hub, however, and processes frames and forwards these based on MAC address information.

Vendor-Specific Topology Extensions

Workgroup Bridge

Perhaps your network contains clients that you want to connect to the wired infrastructure but these devices are in a location where it is difficult to extend actual physical wires. This is the perfect time to have the access point function as a workgroup bridge. The access point extends the wired LAN out to these wireless devices.

Repeater

In this case, the job of the access point is to strengthen the wireless signal from another access point. Perhaps it is strengthening the signal of an access point acting in the workgroup bridge role. When repeaters are used, there must be overlap in the access point cell coverage. In order to provide optimal performance, the overlap needs to be 50%.

Outdoor Wireless Bridge

These access points are typically used within a few miles of each other and are used to connect two or more LANs. The Cisco technology allows the configuration of point-to-point or point-to-multipoint topologies.

Outdoor Mesh Networks

The outdoor mesh network features an access point acting as a root device. This AP has an Ethernet connection to a distribution network and it associates with a Wireless LAN Controller (WLC). The other access points in the design act as mesh APs. All these devices need is power and can act as repeaters as required in order to allow all devices to reach the root access point. While the IEEE is working on a mesh standard called 802.11s, the Cisco solution features Adaptive Wireless Path Protocol (AWPP). AWPP promotes the mesh devices finding the best path back to the root AP.

One of the features students love in the INE 5-Day CCNP bootcamp is the frequent Exam Challenges that are presented to students. Have fun with this sample from SWITCH.

Q1: Examine the configurations shown and the topology. Identify three errors in the configurations.

SW1

interface range fa0/16 – 17

switchport trunk encapsulation dot1q

switchport mode dynamic desirable

no shutdown

channel-group 1 mode on

SW3

interface range fa0/16 – 17

switchport trunk encapsulation dot1q

switchport mode dynamic auto

shutdown

channel-group 3 mode active 

In the first part of this series, we subdivided the processes of EIGRP into four discrete steps, and detailed troubleshooting the first two. This is taken from the 5-Day CCNP bootcamp:

• Discovery of neighbors
• Exchange of topology information
• Best path selection
• Neighbor and topology table maintenance

Let us now discuss path selection and maintenance troubleshooting.

We should all remember that we can view the topology table of EIGRP with the command show ip eigrp topology. Here we can see the successor routes (these are the best routes that are placed in the routing table) and we can see the second best routes, the feasible successor routes. These feasible successor routes are the key to the lightening fast convergence that EIGRP can offer us. When a speaker loses its successor, it can quickly install a feasible successor route in its place.

We need to remember the important rule of feasible successors. The advertised distance of the proposed feasible successor must be less than the feasible distance of the current successor route. This is actually a loop prevention mechanism.

Another big gotcha when it comes to path selection in EIGRP is the configuration of variance to unequal cost load balance. I can remember fighting with this in an INE practice lab long ago when I was preparing for the exam. Something I had no idea of back then...in order to be considered for the unequal load balancing, the alternate paths must be feasible successors! Older editions of CCNP courses never thought to tell us that little nugget!

We should be careful when modifying bandwidth to effect path selection. Cisco gave us delay for this purpose. Modifying the bandwidth can starve EIGRP updates of bandwidth to use. Remember, by default, EIGRP will only use 50% of an interface's bandwidth. We can control this with the command ip bandwidth percent eigrp.

For table maintenance, show ip eigrp topology is critical. Note that in this table, passive is what we want to see. Active indicates there is not a feasible successor and neighbors are being queried for an alternative path. SIA log messages indicate a Stuck in Active issue. Here the router is not receiving a reply to queries. The most common reasons this can occur:

• Bad link
• Congested link
• The query scope if too big (too many routers involved)
• Excessive redundancy is built into the network
• The router CPU is overloaded
• There is a shortage of memory on the router
• There are software defects

When it comes to table maintenance, another excellent troubleshooting command is show ip eigrp topology summary. This command displays the total number of routes in the topology table and the total number of queries the router is waiting on responses for. It also shows a quiescent interface field that shows which interface have no outstanding packets to be sent or acknowledged.

Some of our favorite EIGRP verification commands:

• show ip route eigrp
• show ip protocol
• show ip eigrp neighbor
• show ip eigrp topology
• show ip eigrp topology all-links
• show ip eigrp topology summary
• debug eigrp packet hello
• debug eigrp packet query reply

We are so excited here at INE for the live, online 5-Day CCNP bootcamp that starts Monday, August 16, 2010 . I look forward to seeing many of our aspiring CCIE candidates in this course. These students realize that they really need to improve their foundation Tier 1 knowledge as they seek to conquer the Lab Exam beast.

In this blog post, we are going to provide a sneak peek into some of the awesome information shared in the TSHOOT section of the bootcamp regarding the Troubleshooting of EIGRP. This can prove critical in the Troubleshooting and Configuration sections of the CCIE R&S Lab Exam, as well as the TSHOOT CCNP exam (duh!).

The first thing that you want to master when it comes to troubleshooting EIGRP is the 'workflow" that EIGRP follows in its operation. We can subdivide the processes of this exciting protocol into four discrete steps:

• Discovery of neighbors
• Exchange of topology information
• Best path selection
• Neighbor and topology table maintaince

Discovery of Neighbors

Remember that EIGRP discovers neighbors through bi-directional multicast by default. IP protocol 88 and 224.0.0.10 are the key parameters we need to watch out for here. Could there be issues with NBMA pseudo-broadcast support or filtering causing neighbor discovery to fail? Certainly things to examine in the topology. Also, watch out for the neighbor command under the EIGRP routing process. This feature causes the use of unicast packets for neighbor creation exclusively and must be agreed upon by BOTH neighbors.

Another area we need to be aware of is the attributes that must match in order for neighbors to form. Sure this list is nowhere near as lengthy as the parameters that we have to watch out for in OSPF networks, but the list is just as critical:

• Common Subnet (Must be the primary address - not a secondary)
• Autonomous System Number
• Authentication
• K values (metric weights)

Exchange of Topology Information

When it comes to the exchange of topology information, this is done with unicast. Notice that connectivity for neighborship still requires mutlicast communications (unless you are using the neighbor command).

Remember that EIGRP will only advertise those prefixes that it installs in the routing table. This is an excellent time to review the difference from the Topology Table to the Routing Table.

Important troubleshooting considerations for the exchange of topology information include:

• Automatic summarization in use?
• Split horizon settings
• The use of duplicate router IDs preventing external route introduction
• No seed metric set for external prefixes
• Filtering through the use of distribute lists

Please consider these troubleshooting aspects for these two phases of EIGRP's operation. We will cover more in the next installment coming soon...