EIGRP

Question 1

Successor Route

Answer 1

Route with the lowest metric to the destination

Question 2

Successor

Answer 2

First next-hop router for the successor

Question 3

Feasible Distance

Answer 3

The metric value for the lowest metric path to the destination

Question 4

Reported Distance

Answer 4

The distance reported by a router to reach a destination prefix. The value is the feasible distance for the advertising router

Question 5

Feasibility Condition

Answer 5

For a route to be considered a backup route the reported distance received must be lower than the feasible distance of the successor

Question 6

Feasible Successor

Answer 6

A route that satisfies the feasibility condition and is maintained as a backup route

Question 7

EIGRP IP Protocol and Multicast Address

Answer 7

IP Protocol 88 and Multicast Address 224.0.0.10

Question 8

Equal Cost Multipathing (ECMP)

Answer 8

Used when there are multiple successors. When multiple routes have an equal cost

To avoid ECMP adjust bandwidth or delay on an interface

Question 9

Cisco Express Forwarding (CEF)

Answer 9

Default switching type. Includes the FIB and the Adjacency table

Question 10

FIB Table

Answer 10

Contains an IP network prefix, the next-hop address, and the outgoing interface

R5#sh ip cef

Question 11

Adjacency Table

Answer 11

Contains layer 3 protocol, the outgoing interface, and a precomputed layer 2 headers.

R5#sh adjacency detail

Question 12

Process Switching

Answer 12

Performs IP routing table lookup for each packet that needs to be switched. Most CPU intensive.

You can enable it by disabling CEF

no ip cef global configuration command
no ip route-cache interface command

Question 13

Unequal Cost Multipathing and Variance

Answer 13

To enable unequal cost load balancing you can adjust the metric variance multiplier. Largest FD divided by smallest FD

Example (26368/26112)
(282112/26112)

282112/26368 = 10.7

R5#(config-router) router eigrp 100
variance 11

Question 14

EIGRP Packet Types

Answer 14

Hellos - sent every 5 seconds, hold time 15 seconds
Updates - carry route prefix and metric info
Acknowledgments - unicast Hello packets that carry no data
Queries - gives neighbor 3 minutes to reply
Replies -

Question 15

EIGRP K Values

Answer 15

K1 = 1 Bandwidth
K2 = 0 Bandwidth
K3 = 1 Delay
K4 = 0 Reliability
K5 = 0 Reliability

Weighted metric formula
256 x (bandwidth + delay)