Basic EIGRP configuration procedure

There are two basic configuration procedures for EIGRP

Enabling the EIGRP Routing Process

Allowing routers to process EIGRP

STEP
1

Enable EIGRP on interfaces

Enables an interface to send and receive EIGRP packets, and registers the network address of the enabled interface in the topology table as EIGRP route information.

STEP
2

Enabling the EIGRP Routing Process

The first step is to enable the EIGRP routing process so that it can process EIGRP.To enable the EIGRP routing process, enter the following command in global configuration mode.

Enabling the EIGRP Routing Process

(config)#router eigrp <AS>
(config-router)#

<AS> : AS number

The AS number is an arbitrary number from 1 to 65535. the EIGRP routing process can also be initiated by a single router. In the case of EIGRP. you must match the AS number with the other routers. Because the AS numbers may match the conditions for establishing a neighbor in EIGRP.

Enable EIGRP on interfaces

EIGRP, like RIP and OSPF, is enabled on a per-interface basis. It’s important to clarify that the routing protocol is enabled on the router’s interface.

BGP is the exception, not enabled on the interface.

To enable EIGRP on an interface, use the network command in EIGRP’s configuration mode.

Enable EIGRP on interfaces

(config-router)#network <ip-address> [<wildcard>]

<ip-address> : IP address
<wildcardmask> : Wildcard mask

As with the OSPF network command, the wildcard mask allows for flexibility in specifying the IP address bit pattern. If you omit the wildcard mask, it is treated as a natural mask of the class. The interface whose IP address matches the bit pattern of the specified IP address and the wildcard mask is the interface for which EIGRP is enabled.

A simple configuration example

As an example of such a two-step configuration for EIGRP, consider the following simple network diagram.

Figure EIGRP configuration example
Figure EIGRP configuration example

R1

router eigrp 1
 network 192.168.0.0 0.0.255.255

R1 is a configuration that enables EIGRP on interfaces with IP addresses beginning with “192.168” by checking only the first 16 bits of the wildcard mask. A one-line network command enables EIGRP on three interfaces, E0/0, E0/2, and Se1/0.

R2

router eigrp 1
 network 192.168.2.2 0.0.0.0
 network 192.168.12.2 0.0.0.0

In R2, this is a configuration that specifies an interface with an exact matching IP address with a wildcard mask 32 bits.

R3

router eigrp 1
 network 192.168.3.0
 network 192.168.13.0
 network 192.168.31.0

The R3 configuration is an example of a natural mask of a class when the wildcard mask is omitted.

Other configurations of EIGRP

Router ID

Like OSPF, EIGRP also identifies a router by its router ID. The method for determining the router ID is the same as for OSPF. To configure the router ID manually, use the following command in EIGRP configuration mode.

EIGRP Router ID

(config-router)#eigrp router-id <router-id>

<router-id> : Router ID

Disabling Auto Summary

EIGRP, like RIP, auto-summary at class boundaries. However, it is now rarely used for auto-summary. To disable auto-summary, enter the following command in EIGRP configuration mode

Disabling Auto Summary

(config-router)#no auto-summary

Change the hello interval/hold down timer

The interval between sending Hello packets of EIGRP is the Hello interval. Also, the time at which the neighbor is considered to be down is the hold down timer. To change it, enter the following command in interface configuration mode.

Change the hello interval/hold down timer

(config-if)#ip hello-interval eigrp <AS> <hello>
(config-if)#ip hold-time eigrp <AS> <hold_time>

<AS> : AS number
<hello> : Hello interval
<hold_time> : Hold down timer

passive-interface

There is no need to send EIGRP packets to an interface to which only PCs, servers, etc. are connected and to which no EIGRP router is connected. Such an interface will stop sending EIGRP packets as a passive-interface.

passive-interface

(config-router)#passive-interface <interface-name>

<interface-name> : Interface name for passive-interface

As with OSPF, the passive-interface interface does not establish a neighbor.

unequal cost load balance

To configure unequal cost load balancing, which registers not only the successors but also the feasible successors in the routing table, enter the following command in EIGRP configuration mode.

unequal cost load balance

(config-router)#variance <value>

<value> : coefficient

The default is 1, so it is an equal cost load balance.

Verification of EIGRP

The table below summarizes the main commands used to verify the operation of EIGRP.

Verification commandsSummary
#show ip protocolsDisplays general information about the routing protocol.
#show ip eigrp interfaceDisplays information about EIGRP-enabled interfaces.
#show ip eigrp neighborDisplay the EIGRP neighbor.
#show ip eigrp topologyDisplays the EIGRP topology table.
#show ip route eigrpDisplays the EIGRP route in the routing table.
Table Main EIGRP verification commands

show ip protocols

show ip protocols displays general information about the routing protocol. you can verify the AS number, K-value, variance value, etc. for EIGRP.

R1#show ip protocols
Routing Protocol is "eigrp 1"
  Outgoing update filter list for all interfaces is not set
  Incoming update filter list for all interfaces is not set
  Default networks flagged in outgoing updates
  Default networks accepted from incoming updates
  EIGRP metric weight K1=1, K2=0, K3=1, K4=0, K5=0
  EIGRP maximum hopcount 100
  EIGRP maximum metric variance 20
  Redistributing: eigrp 1
  EIGRP NSF-aware route hold timer is 240s
  Automatic network summarization is in effect
  Automatic address summarization:
    192.168.31.0/24 for Ethernet0/0, Serial1/0
    192.168.13.0/24 for Ethernet0/0, Ethernet0/2
    192.168.12.0/24 for Ethernet0/2, Serial1/0
  Maximum path: 4
  Routing for Networks:
    192.168.0.0/16
  Routing Information Sources:
    Gateway         Distance      Last Update
    192.168.13.3          90      00:00:03
    192.168.12.2          90      00:00:03
    192.168.31.3          90      00:00:03
  Distance: internal 90 external 170

show ip eigrp interface

You can use show ip eigrp interface to check the EIGRP-enabled interfaces.

R1#show ip eigrp interfaces
IP-EIGRP interfaces for process 1
                        Xmit Queue   Mean   Pacing Time   Multicast    Pending
Interface        Peers  Un/Reliable  SRTT   Un/Reliable   Flow Timer   Routes
Et0/0              1        0/0        32       0/2          144           0
Et0/2              1        0/0        25       0/2           64           0
Se1/0              1        0/0        28       0/15          99           0
detailをつけるとより詳細な情報がわかります。
passive-interfaceにしたインタフェースはshow ip eigrp interfaceには表示されなくなります。

show ip eigrp neighbor

Use show ip eigrp neighbor to verify the EIGRP neighbor. as with OSPF. route information is exchanged only after the neighbor is established. it is important to verify EIGRP operation by checking the neighbor using the show ip eigrp neighbor command.

R1#show ip eigrp neighbors
IP-EIGRP neighbors for process 1
H   Address                 Interface       Hold Uptime   SRTT   RTO  Q  Seq
                                            (sec)         (ms)       Cnt Num
2   192.168.31.3            Et0/2             13 00:27:25   25   200  0  11
1   192.168.13.3            Se1/0             13 00:27:29   28   200  0  9
0   192.168.12.2            Et0/0             13 00:28:10   32   200  0  5

show ip eigrp topology

Use the show ip eigrp topolgy command to display the EIGRP topology table successors and feasible successors.

R1#show ip eigrp topology
IP-EIGRP Topology Table for AS(1)/ID(192.168.31.1)
Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,
       r - reply Status, s - sia Status

P 192.168.12.0/24, 1 successors, FD is 281600
        via Connected, Ethernet0/0
P 192.168.13.0/24, 1 successors, FD is 2169856
        via Connected, Serial1/0
P 192.168.2.0/24, 1 successors, FD is 307200
        via 192.168.12.2 (307200/281600), Ethernet0/0
P 192.168.3.0/24, 1 successors, FD is 307200
        via 192.168.31.3 (307200/281600), Ethernet0/2
        via 192.168.13.3 (2195456/281600), Serial1/0
P 192.168.31.0/24, 1 successors, FD is 281600
        via Connected, Ethernet0/2

‘via Connected’ means that this is the EIGRP route generated by the network command. show ip eigrp topology followed by a specific network address for more detailed information.

R1#show ip eigrp topology 192.168.3.0/24
IP-EIGRP (AS 1): Topology entry for 192.168.3.0/24
  State is Passive, Query origin flag is 1, 1 Successor(s), FD is 307200
  Routing Descriptor Blocks:
  192.168.31.3 (Ethernet0/2), from 192.168.31.3, Send flag is 0x0
      Composite metric is (307200/281600), Route is Internal
      Vector metric:
        Minimum bandwidth is 10000 Kbit
        Total delay is 2000 microseconds
        Reliability is 255/255
        Load is 1/255
        Minimum MTU is 1500
        Hop count is 1
  192.168.13.3 (Serial1/0), from 192.168.13.3, Send flag is 0x0
      Composite metric is (2195456/281600), Route is Internal
      Vector metric:
        Minimum bandwidth is 1544 Kbit
        Total delay is 21000 microseconds
        Reliability is 255/255
        Load is 1/255
        Minimum MTU is 1500
        Hop count is 1
detail-linksまたはall-linksをつけるとサクセサとフィージブルサクセサ以外も表示します。

show ip route eigrp

The show ip route eigrp command displays only the EIGRP routes in the routing table.

R1#show ip route eigrp
D    192.168.2.0/24 [90/307200] via 192.168.12.2, 00:15:54, Ethernet0/0
D    192.168.3.0/24 [90/307200] via 192.168.31.3, 00:15:54, Ethernet0/2
                    [90/2195456] via 192.168.13.3, 00:15:54, Serial1/0

There are two codes for the EIGRP root, as follows

CodeSummary
DEIGRP routes
D EXThe routes of a non-EIGRP domain
Table EIGRP route code

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