Routing Notes 01 EIGRP 1 BASICS

SUMMARY

1. Backup Routes via Fast Convergence / Dual
2. Simple Configuration
3. Flexibility in Summarization
4. Unequal Cost LB
5. Distance Vector and Link State combined with backup paths
6. Use its own Layer 4 protocol

EIGRP Tables and Definition

1. Neighbor Table - show ip eigrp neighbors - exchanging routes
2. Topology Table - have the successor (direct path) and feasible successor links
3. Routing Table - picking the best route / DUAL , will actively be used

Feasible Distance (FD)
1. Recived routing updates
2. Adverstice Distance + Link Cost (Metric)

Advertised Distance (AD)
1. How far from a device to another device (Metric COST)

Successor
1. Route with the lowest FD
2. Best and lowest
3. Primary route

Feasible Successor
1. Backup route
2. The AD must be lower than the FD of the successor

Active and Passive Routes
1. Active - Network Down
2. Passive - Network/Route is up

EIGRP Neighbor Relationship

1. Hello - forms relationship
2. Update - sends update
3. Query - ask about routes and backup
4. Reply - Response to query
5. Ack - Acknowledge update, query, and reply message

SIA - stuck in active route, removes the neighbor relationship

Metric Calculation

Bandwidth K
Delay K3 (consider as Static Value can be seen in show IP interface / hop counter)
Reliability K4 and K5 (Dynamic Value)
Load K2 (Dynamic Values)

Real Metric - 256 x (A:slowest bandwidth + B:delays of linsk)

BASE CONFIGURATION

ROUTER A
1. show ip interface brief
2. int s0/0
3. bandwidth 128
4. exit
5. int  s0/1
6. bandwidth 256
7. exit
8. router eigrp 10
9. no auto-summary
auto summary makes it class full
best practice to disable auto summary
10.1 network 192.0.0.0 0.0.0.255
10.2 network 192.0.0.1 0.0.0.0
        network 192.0.1.1 0.0.0.0
        network 192.0.2.1 0.0.0.0
10.3 network 192.0.0.0
10.4 network 0.0.0.0 255.255.255.255

show ip protocol
192.0.0.0
192.0.0.1/32
192.0.1.1/32
192.0.2.1/32
192.0.0.0/24
0.0.0.0
expected output of 10.1-4

ROUTER B
router eigp 10
network 10.1.0.0 0.0.0.255
no auto summary

ROUTER C
router eigrp 10
network 10.1.0.0 0.0.0.255
no auto summary

Show commands to check if eigrp is running

show ip eigrp neighbors
show ip eigrp interfaces