Routing protocol EIGRP dapat melakukan load balance jika terdapat dua atau lebih jalur yang masing-masing nilai metricnya sama, tetapi terkadang muncul suatu keadaan dimana ada beberapa jalur yang tujuannya sama tetapi nilai metricnya berbeda, hal ini menyebabkan EIGRP hanya memilih satu jalur saja (redundant), tetapi sebenarnya kita dapat mengakalinya agar dapat load balance meski nilai metric pada masing-masing jalur berbeda.
Untuk melakukan Un-Equal load balance kita perlu mengkonfigurasi nilai variance, nilai ini didapatkan dari hasi bagi nilai FD masing-masing jalur. Berikut ini adalah topologinya :
Untuk mencapai R4 dari R1 terdapat dua jalur yaitu lewat e0/0 dan e0/1, kemudian nilai bandwidth pada e0/1 kita kecilkan agar nilai metric antara e0/0 dan e0/1 berbeda sehingga jalur di e0/0 akan dipilih menjadi jalur utama, kemudian kita konfigurasi variance agar dapat melakukan load balance meskipun nilai metricnya berbeda.
Pertama kita ubah nilai bandwitdh di interface e0/1 Router R1 agar nilai metricnya berubah dan tidak sama dengan e0/0 :
Untuk melakukan Un-Equal load balance kita perlu mengkonfigurasi nilai variance, nilai ini didapatkan dari hasi bagi nilai FD masing-masing jalur. Berikut ini adalah topologinya :
Pertama kita ubah nilai bandwitdh di interface e0/1 Router R1 agar nilai metricnya berubah dan tidak sama dengan e0/0 :
R1(config)#int e0/1 R1(config-if)#band 500 R1(config-if)#exi
IP Addressing
R1
R1(config)#int lo0 R1(config-if)#ip add 1.1.1.1 255.255.255.255 R1(config-if)#exi R1(config)#int e0/0 R1(config-if)#ip add 12.12.12.1 255.255.255.0 R1(config-if)#no sh R1(config-if)#exi R1(config)#int e0/1 R1(config-if)#ip add 13.13.13.1 255.255.255.0 R1(config-if)#no sh R1(config-if)#exi
R2
R2(config)#int lo0 R2(config-if)#ip add 2.2.2.2 255.255.255.255 R2(config-if)#exi R2(config)#int e0/0 R2(config-if)#ip add 12.12.12.2 255.255.255.0 R2(config-if)#no sh R2(config-if)#exi R2(config)#int e0/1 R2(config-if)#ip add 24.24.24.2 255.255.255.0 R2(config-if)#no sh R2(config-if)#exi
R3
R3(config)#int lo0 R3(config-if)#ip add 3.3.3.3 255.255.255.255 R3(config-if)#exi R3(config)#int e0/0 R3(config-if)#ip add 13.13.13.3 255.255.255.0 R3(config-if)#no sh R3(config-if)#exi R3(config)#int e0/1 R3(config-if)#ip add 34.34.34.3 255.255.255.0 R3(config-if)#no sh R3(config-if)#exi
R4
R4(config)#int lo0 R4(config-if)#ip add 4.4.4.4 255.255.255.255 R4(config-if)#ex R4(config)#int e0/0 R4(config-if)#ip add 24.24.24.4 255.255.255.0 R4(config-if)#no sh R4(config-if)#exi R4(config)#int e0/1 R4(config-if)#ip add 34.34.34.4 255.255.255.0 R4(config-if)#no sh R4(config-if)#exi
Routing EIGRP
R1
R1(config)#router eigrp 1 R1(config-router)#no auto-summ R1(config-router)#net 1.1.1.1 0.0.0.0 R1(config-router)#net 12.12.12.0 0.0.0.255 R1(config-router)#net 13.13.13.0 0.0.0.255 R1(config-router)#exi
R2
R2(config)#router eigrp 1 R2(config-router)#no auto-summ R2(config-router)#net 2.2.2.2 0.0.0.0 R2(config-router)#net 24.24.24.0 0.0.0.255 R2(config-router)#net 12.12.12.0 0.0.0.255 R2(config-router)#exi
R3
R3(config)#router eigrp 1 R3(config-router)#no auto-summ R3(config-router)#net 3.3.3.3 0.0.0.0 R3(config-router)#net 13.13.13.0 0.0.0.255 R3(config-router)#net 34.34.34.0 0.0.0.255 R3(config-router)#exi
R4
R4(config)#router eigrp 1 R4(config-router)#no auto-summ R4(config-router)#net 4.4.4.4 0.0.0.0 R4(config-router)#net 24.24.24.0 0.0.0.255 R4(config-router)#net 34.34.34.0 0.0.0.255 R4(config-router)#exiLalu kita lihat Routing table di R1
R1(config)#do sh ip ro
Codes: L - local, 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, H - NHRP, l - LISP
a - application route
+ - replicated route, % - next hop override
Gateway of last resort is not set
1.0.0.0/32 is subnetted, 1 subnets
C 1.1.1.1 is directly connected, Loopback0
2.0.0.0/32 is subnetted, 1 subnets
D 2.2.2.2 [90/409600] via 12.12.12.2, 03:01:27, Ethernet0/0
3.0.0.0/32 is subnetted, 1 subnets
D 3.3.3.3 [90/460800] via 12.12.12.2, 00:00:26, Ethernet0/0
4.0.0.0/32 is subnetted, 1 subnets
D 4.4.4.4 [90/435200] via 12.12.12.2, 00:00:26, Ethernet0/0
12.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C 12.12.12.0/24 is directly connected, Ethernet0/0
L 12.12.12.1/32 is directly connected, Ethernet0/0
13.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C 13.13.13.0/24 is directly connected, Ethernet0/1
L 13.13.13.1/32 is directly connected, Ethernet0/1
24.0.0.0/24 is subnetted, 1 subnets
D 24.24.24.0 [90/307200] via 12.12.12.2, 00:00:26, Ethernet0/0
34.0.0.0/24 is subnetted, 1 subnets
D 34.34.34.0 [90/332800] via 12.12.12.2, 00:00:26, Ethernet0/0
Dan terlihat 4.4.4.4 hanya memiliki satu jalur, kemudian kita lihat nilai metric pada masing-masing jalur :
R1#sh ip eigrp topology 4.4.4.4/32
EIGRP-IPv4 Topology Entry for AS(1)/ID(1.1.1.1) for 4.4.4.4/32
State is Passive, Query origin flag is 1, 1 Successor(s), FD is 435200
Descriptor Blocks:
12.12.12.2 (Ethernet0/0), from 12.12.12.2, Send flag is 0x0
Composite metric is (435200/409600), route is Internal
Vector metric:
Minimum bandwidth is 10000 Kbit
Total delay is 7000 microseconds
Reliability is 255/255
Load is 1/255
Minimum MTU is 1500
Hop count is 2
Originating router is 4.4.4.4
13.13.13.3 (Ethernet0/1), from 13.13.13.3, Send flag is 0x0
Composite metric is (5299200/409600), route is Internal
Vector metric:
Minimum bandwidth is 500 Kbit
Total delay is 7000 microseconds
Reliability is 255/255
Load is 1/255
Minimum MTU is 1500
Hop count is 2
Kemudian kedua nilai yang ditebalkan itu kita bagi 5299200 dengan 435200 dan hasilnya 12,176470588 jika komanya berlebih berapapun nilainya bulatkan saja, maka nilai variancenya adalah 13.
R1(config)#router eigrp 1 R1(config-router)#variance 13 R1(config-router)#exDan kita lihat hasilnya pada Routing table R1.
R1(config)#do sh ip ro
Codes: L - local, 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, H - NHRP, l - LISP
a - application route
+ - replicated route, % - next hop override
Gateway of last resort is not set
1.0.0.0/32 is subnetted, 1 subnets
C 1.1.1.1 is directly connected, Loopback0
2.0.0.0/32 is subnetted, 1 subnets
D 2.2.2.2 [90/409600] via 12.12.12.2, 00:00:30, Ethernet0/0
3.0.0.0/32 is subnetted, 1 subnets
D 3.3.3.3 [90/5273600] via 13.13.13.3, 00:00:30, Ethernet0/1
[90/460800] via 12.12.12.2, 00:00:30, Ethernet0/0
4.0.0.0/32 is subnetted, 1 subnets
D 4.4.4.4 [90/5299200] via 13.13.13.3, 00:00:30, Ethernet0/1
[90/435200] via 12.12.12.2, 00:00:30, Ethernet0/0
12.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C 12.12.12.0/24 is directly connected, Ethernet0/0
L 12.12.12.1/32 is directly connected, Ethernet0/0
13.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C 13.13.13.0/24 is directly connected, Ethernet0/1
L 13.13.13.1/32 is directly connected, Ethernet0/1
24.0.0.0/24 is subnetted, 1 subnets
D 24.24.24.0 [90/307200] via 12.12.12.2, 00:00:30, Ethernet0/0
34.0.0.0/24 is subnetted, 1 subnets
D 34.34.34.0 [90/332800] via 12.12.12.2, 00:00:30, Ethernet0/0
Dan terlihat jalur sudah di load balance kembali, untuk membuktikannya kita lakukan traceroute.
R1#traceroute 4.4.4.4 so lo0
Type escape sequence to abort.
Tracing the route to 4.4.4.4
VRF info: (vrf in name/id, vrf out name/id)
1 12.12.12.2 0 msec 0 msec 1 msec
2 24.24.24.4 0 msec
34.34.34.4 0 msec
24.24.24.4 1 msec
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