EIGRP (Enchanced Interior Gatway Routing Protocol)

EIGRP termasuk protokol proprietari milik Cisco, dan hanya bisa dijalankan pada router Cisco, merupakan protokol routing terbaik jika saja kita memiliki router Cisco. EIGRP menggunakan algoritma DUAL untuk menandingi OSPF.

Kelebihan-kelebihan EIGRP

1. Satu-satunya protokol routing yang menggunakan route backup. Selain memaintain tabel routing terbaik, EIGRP juga menyimpan backup terbaik untuk setiap route sehingga setiap kali terjadi kegagalan pada jalur utama, maka EIGRP menawarkan jalur alternatif tanpa menunggu waktu convergence.
2. Mudah dikonfigurasi semudah RIP.
3. Summarization dapat dilakukan dimana saja dan kapan saja. Pada OSPF summarization hanya bisa dilakukan di ABR dan ASBR.
4. EIGRP satu-satunya yang dapat melakukan unequal load balancing.
5. Kombinasi terbaik dari protokol distance vector dan link state.
6. Mendukung multiple protokol network  (IP, IPX, dan lain-lain).

Router yang menjalankan EIGRP me-maintain 3 jenis tabel

• Tabel neighbor: seperti OSPF, EIGRP juga menjalin neighbor relationship tetapi dengan cara yang lebih mudah.
• Tabel topologi
• Tabel routing

Konfigurasi EIGRP

R1#

R1#conf t

Enter configuration commands, one per line.  End with CNTL/Z.

R1(config)#router eigrp 10

R1(config-router)#network 192.168.1.0 0.0.0.255

R1(config-router)#^Z

R1#

R2#conf t

Enter configuration commands, one per line.  End with CNTL/Z.

R2(config)#router eigrp 10

R2(config-router)#network 192.168.0.0 0.0.255.255

R2(config-router)#^Z

R2#

Setelah ini kita bisa melihat neighbor telah terdeteksi

R2#sh ip eigrp neighbors

IP-EIGRP neighbors for process 10

H   Address                 Interface       Hold Uptime   SRTT   RTO  Q  Seq (sec)         (ms)       Cnt Num

0   192.168.1.1             Fa0/0             11 00:02:33   57   342  0  3

Kemudian konfigurasi R3 sebagai berikut, sekedar informasi, EIGRP tidak menggunakan konsep area seperti pada ospf

R3#conf t

Enter configuration commands, one per line.  End with CNTL/Z.

R3(config)#router eigrp 10

R3(config-router)#network 192.168.0.0 0.0.255.255

R3(config-router)#network 172.16.0.0 0.0.255.255

R3(config-router)#^Z

R3#

Setelah ini kita bisa mengecek tabel routing untuk melihat entri-entri route yang didapatkan dari proses EIGRP

R3#sh ip route

Codes: C – connected, S – static, R – RIP, M – mobile, B – BGP

D – EIGRP, EX – EIGRP external, O – OSPF, IA – OSPF inter area

N1 – OSPF NSSA external type 1, N2 – OSPF NSSA external type 2

E1 – OSPF external type 1, E2 – OSPF external type 2

i – IS-IS, su – IS-IS summary, L1 – IS-IS level-1, L2 – IS-IS level-2

ia – IS-IS inter area, * – candidate default, U – per-user static route

o – ODR, P – periodic downloaded static route

Gateway of last resort is not set

D    192.168.10.0/24 [90/2172416] via 192.168.2.1, 00:01:21, Serial0/0

172.16.0.0/16 is variably subnetted, 9 subnets, 2 masks

C       172.16.4.0/24 is directly connected, Loopback4

C       172.16.5.0/24 is directly connected, Loopback5

C       172.16.6.0/24 is directly connected, Loopback6

C       172.16.7.0/24 is directly connected, Loopback7

C       172.16.0.0/24 is directly connected, Loopback0

D       172.16.0.0/16 is a summary, 00:01:10, Null0

C       172.16.1.0/24 is directly connected, Loopback1

C       172.16.2.0/24 is directly connected, Loopback2

C       172.16.3.0/24 is directly connected, Loopback3

D    192.168.20.0/24 [90/2172416] via 192.168.2.1, 00:01:21, Serial0/0

D    192.168.1.0/24 [90/2172416] via 192.168.2.1, 00:01:21, Serial0/0

C    192.168.2.0/24 is directly connected, Serial0/0

C    192.168.3.0/24 is directly connected, Ethernet1/0

Mari kita lihat tabel routing pada R2 seperti berikut

R2#sh ip route

Codes: C – connected, S – static, R – RIP, M – mobile, B – BGP

D – EIGRP, EX – EIGRP external, O – OSPF, IA – OSPF inter area

N1 – OSPF NSSA external type 1, N2 – OSPF NSSA external type 2

E1 – OSPF external type 1, E2 – OSPF external type 2

i – IS-IS, su – IS-IS summary, L1 – IS-IS level-1, L2 – IS-IS level-2

ia – IS-IS inter area, * – candidate default, U – per-user static route

o – ODR, P – periodic downloaded static route

Gateway of last resort is not set

C    192.168.10.0/24 is directly connected, FastEthernet0/0.10

D    172.16.0.0/16 [90/2297856] via 192.168.2.2, 00:03:10, Serial1/0

C    192.168.20.0/24 is directly connected, FastEthernet0/0.20

C    192.168.1.0/24 is directly connected, FastEthernet0/0

C    192.168.2.0/24 is directly connected, Serial1/0

D    192.168.3.0/24 [90/2195456] via 192.168.2.2, 00:03:21, Serial1/0

Perhatikan, EIGRP otomatis melakukan summarization pada network 172.16.0.0/16, auto-summarization ini dilakukan setiap ditemukan network yang discontiguous (tidak kontinyu). Contohnya diatas R3 terhubung pada network kelas A 192.168.2.0 dengan network kelas B 172.16.0.0.
Untuk men-disable fitur ini kita bisa mengeksekusi perintah no auto-summary

R3#conf t

Enter configuration commands, one per line.  End with CNTL/Z.

R3(config)#router eigrp 10

R3(config-router)#no auto-summary

R3(config-router)#^Z

R3#

Kini kita lihat kembali tabel routing pada R2

R2#sh ip route

Codes: C – connected, S – static, R – RIP, M – mobile, B – BGP

D – EIGRP, EX – EIGRP external, O – OSPF, IA – OSPF inter area

N1 – OSPF NSSA external type 1, N2 – OSPF NSSA external type 2

E1 – OSPF external type 1, E2 – OSPF external type 2

i – IS-IS, su – IS-IS summary, L1 – IS-IS level-1, L2 – IS-IS level-2

ia – IS-IS inter area, * – candidate default, U – per-user static route

o – ODR, P – periodic downloaded static route

Gateway of last resort is not set

C    192.168.10.0/24 is directly connected, FastEthernet0/0.10

172.16.0.0/24 is subnetted, 8 subnets

D       172.16.4.0 [90/2297856] via 192.168.2.2, 00:00:46, Serial1/0

D       172.16.5.0 [90/2297856] via 192.168.2.2, 00:00:46, Serial1/0

D       172.16.6.0 [90/2297856] via 192.168.2.2, 00:00:46, Serial1/0

D       172.16.7.0 [90/2297856] via 192.168.2.2, 00:00:46, Serial1/0

D       172.16.0.0 [90/2297856] via 192.168.2.2, 00:00:46, Serial1/0

D       172.16.1.0 [90/2297856] via 192.168.2.2, 00:00:46, Serial1/0

D       172.16.2.0 [90/2297856] via 192.168.2.2, 00:00:46, Serial1/0

D       172.16.3.0 [90/2297856] via 192.168.2.2, 00:00:46, Serial1/0

C    192.168.20.0/24 is directly connected, FastEthernet0/0.20

C    192.168.1.0/24 is directly connected, FastEthernet0/0

C    192.168.2.0/24 is directly connected, Serial1/0

D    192.168.3.0/24 [90/2195456] via 192.168.2.2, 00:08:30, Serial1/0

Summarization dimana saja kapan saja

Seperti disinggung diatas, route summarization pada OSPF hanya bisa dilakukan pada ABR dan ASBR saja, tetapi pada EIGRP kita bisa melakukan summarization pada router manapun yang kita kehendaki.  Misal kita ingin melakukan summarization pada network 172.16.0.0 – 172.16.7.0 pada R3, sehingga hanya 1 entri yang di advertise ke router R2

R3#conf t

Enter configuration commands, one per line.  End with CNTL/Z.

R3(config)#int s0/0

R3(config-if)#ip summary-address eigrp 10 172.16.0.0 255.255.248.0

R3(config-if)#^Z

R3#

Route summarization harus dikonfigurasi dibawah setiap interface dimana entri route tersebut akan di advertise, dalam hal ini interface serial0/0. Sekarang seharusnya entri route yang didapatkan oleh R2 hanya berupa 1 entri route summary

R2#sh ip route

Gateway of last resort is not set

C    192.168.10.0/24 is directly connected, FastEthernet0/0.10

172.16.0.0/21 is subnetted, 1 subnets

D       172.16.0.0 [90/2297856] via 192.168.2.2, 00:00:07, Serial1/0

C    192.168.20.0/24 is directly connected, FastEthernet0/0.20

C    192.168.1.0/24 is directly connected, FastEthernet0/0

C    192.168.2.0/24 is directly connected, Serial1/0

D    192.168.3.0/24 [90/2195456] via 192.168.2.2, 00:15:08, Serial1/0

R2#