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Маршрутизаторы R1, R2 и R3 принадлежат area 0 и соединены высокоскоростными линками. Маршрутизаторы также являются ABR для area 1 и 2.
При традиционной конфигурации OSPF линки R1-R2 и R2-R3 будут принадлежать Area 0. При этом трафик сетей, включенных в маршрутизаторы R21 и R26 будет проходить по маршруту R21-R22-R23-R24-R25-R26,
так как маршруты, полученные от ABR являются inter area и проигрывают маршрутам intra area вне зависимости от метрики. Аналогичная ситуация с маршрутизаторами R11 и R14.
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К маршрутизаторам R11, R14, R21 и R26 подключены соответственно сети 192.168.11.0/24, 192.168.14.0/24, 192.168.21.0/24 и 192.168.26.0/24. Метрики Intra Area линков area 1 и 2 увеличены.
Видно, что сети что связность между сетями маршрутизаторов одной area осуществляется через intra area линки с завышенной метрикой
| Блок кода |
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0/ME5200:R1# sh route
Tue Aug 29 18:04:08 2023
Codes: C - connected, S - static, O - OSPF, B - BGP, L - local
IA - OSPF inter area, EA - OSPF intra 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, L1 - IS-IS level-1, L2 - IS-IS level-2,
LE1 - IS-IS level1 external, LE2 - IS-IS level2 external
BI - BGP internal, BE - BGP external, BV - BGP vpn,
BL - BGP labeled, R - RIP
O EA 10.0.0.32/30 via 10.0.0.37 [30/102], 02h15m43s, te0/0/5.952
C 10.0.0.36/30 is directly connected, 04d00h20m, te0/0/5.952
L 10.0.0.38/32 is directly connected, 04d00h20m, te0/0/5.952
O EA 10.0.0.52/30 via 10.0.0.37 [30/101], 02h15m43s, te0/0/5.952
C 10.0.0.56/30 is directly connected, 06h53m59s, te0/0/32
L 10.0.0.57/32 is directly connected, 06h53m59s, te0/0/32
O EA 10.0.0.60/30 via 10.0.0.58 [30/2], 06h36m05s, te0/0/32
O EA 10.0.0.64/30 via 10.0.0.74 [30/102], 02h27m00s, te0/0/31
O EA 10.0.0.68/30 via 10.0.0.74 [30/101], 02h27m00s, te0/0/31
C 10.0.0.72/30 is directly connected, 02h27m15s, te0/0/31
L 10.0.0.73/32 is directly connected, 02h27m15s, te0/0/31
O EA 192.168.11.0/24 via 10.0.0.74 [30/1], 02h21m09s, te0/0/31
O EA 192.168.14.0/24 via 10.0.0.74 [30/102], 02h20m39s, te0/0/31
O EA 192.168.21.0/24 via 10.0.0.37 [30/2], 02h14m29s, te0/0/5.952
O EA 192.168.26.0/24 via 10.0.0.37 [30/102], 02h13m07s, te0/0/5.952
==============================================================
0/FMC0:R11# sh route
Tue Aug 29 11:08:33 2023
Codes: C - connected, S - static, O - OSPF, B - BGP, L - local
IA - OSPF inter area, EA - OSPF intra 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, L1 - IS-IS level-1, L2 - IS-IS level-2,
LE1 - IS-IS level1 external, LE2 - IS-IS level2 external
BI - BGP internal, BE - BGP external, BV - BGP vpn,
BL - BGP labeled, R - RIP
O IA 10.0.0.32/30 via 10.0.0.73 [30/103], 02h20m02s, te0/0/6
O IA 10.0.0.36/30 via 10.0.0.73 [30/2], 02h31m24s, te0/0/6
O IA 10.0.0.52/30 via 10.0.0.73 [30/102], 02h20m02s, te0/0/6
O IA 10.0.0.56/30 via 10.0.0.73 [30/2], 02h31m24s, te0/0/6
O IA 10.0.0.60/30 via 10.0.0.73 [30/3], 02h31m24s, te0/0/6
O EA 10.0.0.64/30 via 10.0.0.69 [30/101], 02h33m51s, te0/0/5
C 10.0.0.68/30 is directly connected, 02h35m43s, te0/0/5
L 10.0.0.70/32 is directly connected, 02h35m43s, te0/0/5
C 10.0.0.72/30 is directly connected, 02h35m43s, te0/0/6
L 10.0.0.74/32 is directly connected, 02h35m43s, te0/0/6
C 192.168.11.0/24 is directly connected, 00h18m14s, te0/0/5.15
L 192.168.11.1/32 is directly connected, 00h18m14s, te0/0/5.15
O EA 192.168.14.0/24 via 10.0.0.69 [30/101], 02h25m03s, te0/0/5
O IA 192.168.21.0/24 via 10.0.0.73 [30/3], 02h18m48s, te0/0/6
O IA 192.168.26.0/24 via 10.0.0.73 [30/103], 02h17m26s, te0/0/6
==============================================================
R26#sh ip route
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, p - overrides from PfR
Gateway of last resort is not set
10.0.0.0/8 is variably subnetted, 18 subnets, 3 masks
C 10.0.0.32/30 is directly connected, GigabitEthernet1.951
L 10.0.0.34/32 is directly connected, GigabitEthernet1.951
O 10.0.0.36/30 [110/101] via 10.0.0.53, 17:59:45, GigabitEthernet1.950
C 10.0.0.52/30 is directly connected, GigabitEthernet1.950
L 10.0.0.54/32 is directly connected, GigabitEthernet1.950
O IA 10.0.0.56/30 [110/2] via 10.0.0.33, 03:38:19, GigabitEthernet1.951
O IA 10.0.0.60/30 [110/2] via 10.0.0.33, 03:38:19, GigabitEthernet1.951
O IA 10.0.0.64/30 [110/3] via 10.0.0.33, 03:38:19, GigabitEthernet1.951
O IA 10.0.0.68/30 [110/103] via 10.0.0.33, 03:38:19, GigabitEthernet1.951
O IA 10.0.0.72/30 [110/3] via 10.0.0.33, 03:38:19, GigabitEthernet1.951
192.168.11.0/32 is subnetted, 1 subnets
O IA 192.168.11.1 [110/3] via 10.0.0.33, 03:38:19, GigabitEthernet1.951
192.168.14.0/32 is subnetted, 1 subnets
O IA 192.168.14.1 [110/4] via 10.0.0.33, 03:38:19, GigabitEthernet1.951
192.168.21.0/32 is subnetted, 1 subnets
O 192.168.21.1 [110/101] via 10.0.0.53, 17:59:45, GigabitEthernet1.950
192.168.26.0/24 is variably subnetted, 2 subnets, 2 masks
C 192.168.26.0/24 is directly connected, Loopback15
L 192.168.26.1/32 is directly connected, Loopback15 |
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