Lab 2-1 Debrief
Implementing an EIGRP-Based Solution
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Lab Topology
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Lab Review: What Did You Accomplish?
 Task 1: Configure Basic EIGRP
– What steps did you take to configure the EIGRP routing
protocol and advertise all of the specific IP subnets used in the
network?
 Task 2: Influence EIGRP Path Selection
– What must be changed so that the primary path is preferred
and the secondary path remains as a backup?
 Task 3: Optimize EIGRP Operation
– How do you prevent the formation of an adjacency, as well as
preserve interface bandwidth and CPU resources?
 Task 4: Scale EIGRP Operation
– How is summarization configured in order to improve
convergence time and add to stability?
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Verification
 Did you have enough information to create the implementation
plan?
 Do the EIGRP-enabled routers form the adjacencies?
 Do you see all of the EIGRP-advertised networks in the IP routing
table as EIGRP routes?
 Do you see two routes in the IP routing table after manipulating
the path where the correct one is preferred?
 You cannot see the adjacency where the EIGRP routing protocol
packets are suppressed, but the path to the destination still exists
via another route; why is this?
 Do you see a summary route to Null0 interface as well as many
more-specific subnets?
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Checkpoints
 Configure the EIGRP routing protocol
 Advertise only specific subnets used in the network
 Manipulate the path by changing the metric
 Ensure the backup path still exists in the IP routing table
 Suppress the EIGRP routing protocol packet to preserve interface
bandwidth and CPU resources without filtering
 Enable manual summarization to hide more specific subnets and
improve stability
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Sample Solution
 EIGRP is configured on the routers.
 Specific subnets used in the network are advertised.
 The metric for the link between routers R1 and R3 is changed.
 The LAN interfaces on routers R1 and R3 are configured as passive.
 Summarization is configured on router R1.
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Alternative Solutions
 EIGRP can be configured per interface or globally
 Different metrics, administrative distance, and filtering can be applied
 Static routes can be used and EIGRP can be disabled between
routers R1 and BBR1.
 The use of another routing protocol can be an alternative solution,
which is not realistic.
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Q and A
 Why is routing protocol selection important?
 Why is changing the metric important?
 Does filtering preserve CPU router resources?
 Why does the passive-interface command result in no adjacency
between the routers?
 Why does summarizing the router IP routing table contain a
summary route to Null0 as well as more specific subnets?
 Why do the IP routing tables for some routers contain only a
summary route?
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Summary
 Configure EIGRP and advertise all of the specific IP subnets in
the network.
 Influencing EIGRP Path Selection can be applied by using a
changing metric and backup path still exists in the IP routing table.
 By suppressing EIGRP routing packets, an EIGRP adjacency is
not formed and the routing updates are not exchanged which
results in more interface bandwidth and less CPU cycles used.
 Summarization decreases the size of the IP routing table, as only
the summary route is present. The summarizing router has a
summary route to the Null0 interface, as well as routes to morespecific subnets.
© 2009 Cisco Systems, Inc. All rights reserved.
ROUTE v1.0—2-9
© 2009 Cisco Systems, Inc. All rights reserved.
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