Roteadores utilizando OSPF em diferentes áreas
Como já foi dito na descrição do teste do OSPF, a existência de múltiplas áreas se deve a necessidade de colocarmos limites na troca de informações entre os roteadores, isto é, controlar o flooding na rede.
Um roteador que tem todas as suas interfaces numa mesma área é chamado de Internal Router (IR), Um roteador que tem suas interfaces em múltiplas áreas é chamado de Area Border Router (ABR), e tem o dever de repassar toda a informação de tabela das outras áreas.
Normalmente, toda informação é concentrada no backbone, também chamado de área 0 e daí repassada para outras áreas, que têm que ser fisicamente conectadas a ele. Podemos então perceber que os roteadores pertencentes à esta área são ABR.
No nosso caso, os ABR são os roteadores cisco1 e cisco2. E tanto o cisco 4000 quanto o cisco3 são do tipo IR.
Comandos para os roteadores 4000, cisco1, cisco2 e cisco3 Configuração de uma interface serial: <4000># <4000>#conf t Enter configuration commands, one per line. End with CNTL/Z. <4000>(config)#int s1 <4000>(config-if)#ip address 192.80.209.14 255.255.255.0 <4000>(config-if)#clock rate 800000 <4000>(config-if)# Configuração de uma interface ethernet: <4000># <4000>#conf t Enter configuration commands, one per line. End with CNTL/Z. <4000>(config)#int e0 <4000>(config-if)#ip address 192.80.100.1 255.255.255.0 <4000>(config-if)# Configuração de uma interface loopback: <4000>#conf t Enter configuration commands, one per line. End with CNTL/Z. <4000>(config)#int lo0 <4000>(config-if)#ip address 200.20.6.1 255.255.255.0 <4000>(config-if)# Habilitação do protocolo OSPF: <4000>#conf t Enter configuration commands, one per line. End with CNTL/Z. <4000>(config)#router ospf 1 <4000>(config-router)# Anúncio das redes pelo OSPF: cisco1# cisco1#conf t Enter configuration commands, one per line. End with CNTL/Z. cisco1(config)#router ospf 1 cisco1(config-router)#network 192.80.209.13 0.0.0.255 area1 cisco1(config-router)#network 200.156.10.1 0.0.0.255 area 1 cisco1(config-router)#network 200.20.94.81 0.0.0.255 area 0 cisco1(config-router)# cisco2# cisco2#conf t Enter configuration commands, one per line. End with CNTL/Z. cisco2(config)#router ospf 1 cisco2(config-router)#network 200.20.94.1 0.0.0.255 area 0 cisco2(config-router)#network 200.20.3.1 0.0.0.255 area 2 cisco2(config-router)#network 200.20.4.1 0.0.0.255 area 2 cisco2(config-router)# cisco3# cisco3#conf t Enter configuration commands, one per line. End with CNTL/Z. cisco3(config)#router ospf 1 cisco3(config-router)#network 200.20.4.2 0.0.0.255 area 2 cisco3(config-router)#network 139.82.10.1 0.0.0.255 area 2 cisco3(config-router)# cisco3# <4000>#conf t Enter configuration commands, one per line. End with CNTL/Z. <4000>(config)#router ospf 1 <4000>(config-router)#network 192.80.209.14 0.0.0.255 area 1 <4000>(config-router)#network 192.80.100.1 0.0.0.255 area 1 <4000>(config-router)#network 200.20.6.1 0.0.0.255 area 1 <4000>(config-router)# Salvando as configurações: <4000># <4000>#copy running-config startup-config Building configuration... [OK] <4000># Obs: para o cisco3 usar o comando 'write' cisco3# cisco3#write #####[OK] cisco3#
SHOW RUNNING -CONFIG Este comando é utilizado para verificar a configuração do roteador. Observar se a interface está UP/DOWN, quais os IPs de cada interface e que redes são anunciadas por OSPF com suas respectivas áreas. Resultados 4000 <4000># <4000>#show running-config Building configuration... Current configuration: ! version 11.3 service timestamps debug uptime service timestamps log uptime no service password-encryption ! hostname <4000> ! ! ! ! ! interface Loopback0 ip address 200.20.6.1 255.255.255.0 ! interface Ethernet0 ip address 192.80.100.1 255.255.255.0 ! interface Ethernet1 no ip address shutdown ! interface Serial0 no ip address no ip mroute-cache shutdown no fair-queue ! interface Serial1 ip address 192.80.209.14 255.255.255.0 clockrate 800000 ! interface Serial2 ip address 192.80.150.1 255.255.255.0 shutdown clockrate 800000 ! interface Serial3 no ip address shutdown ! router ospf 1 network 192.80.100.0 0.0.0.255 area 1 network 192.80.209.0 0.0.0.255 area 1 network 200.20.6.0 0.0.0.255 area 1 ! ip classless ! ! ! line con 0 line aux 0 line vty 0 4 login ! end <4000># Resultados cisco1 cisco1# cisco1#show running-config Building configuration... Current configuration: ! version 11.2 service timestamps debug uptime service timestamps log uptime service password-encryption no service udp-small-servers no service tcp-small-servers ! hostname cisco1 ! enable password 7 06100E324F41 ! ip subnet-zero no ip source-route no ip domain-lookup ! interface Loopback0 ip address 200.156.10.1 255.255.255.0 ! interface Ethernet0 ip address 200.20.94.81 255.255.255.0 ! interface Serial0 ip address 192.80.209.13 255.255.255.0 ! interface Serial1 no ip address shutdown ! router ospf 1 network 192.80.209.0 0.0.0.255 area 1 network 200.156.10.0 0.0.0.255 area 1 network 200.20.94.0 0.0.0.255 area 0 ! ip classless ! ! line con 0 exec-timeout 0 0 password 7 060C0E2F494208 login line aux 0 line vty 0 4 password 7 000E120801570A login ! end cisco1# Resultados cisco2 cisco2# cisco2#show running-config Building configuration... Current configuration: ! version 11.2 service password-encryption no service udp-small-servers no service tcp-small-servers ! hostname cisco2 ! enable secret 5 $1$jibr$cTHEQancHt3LUqhsNxGXG0 ! no ip domain-lookup ! interface Loopback0 ip address 200.20.3.1 255.255.255.0 ! interface Ethernet0 ip address 200.20.94.1 255.255.255.0 no ip directed-broadcast ! interface Serial0 ip address 192.80.209.125 255.255.255.252 no ip directed-broadcast ip ospf network point-to-multipoint shutdown clockrate 800000 ! interface Serial1 ip address 200.20.4.1 255.255.255.0 no ip directed-broadcast ! router ospf 1 network 200.20.3.0 0.0.0.255 area 2 network 200.20.4.0 0.0.0.255 area 2 network 200.20.94.0 0.0.0.255 area 0 ! ip classless ! ! line con 0 password 7 0501070124404F line aux 0 password 7 0501070124404F line vty 0 1 password 7 0501070124404F login line vty 2 password 7 082B4D400C1504 login line vty 3 4 password 7 044904131B245E login ! end cisco2# Resultados cisco3 cisco3# cisco3#show configuration Using 444 out of 32762 bytes ! version 10.2 ! hostname cisco3 ! ! ! interface Loopback0 ip address 139.82.10.1 255.255.255.0 ! interface Ethernet0 ip address 192.80.100.1 255.255.255.0 shutdown ! interface Serial0 ip address 200.20.5.1 255.255.255.0 shutdown ! interface Serial1 ip address 200.20.4.2 255.255.255.0 clockrate 800000 ! router ospf 1 network 200.20.4.0 0.0.0.255 area 2 network 139.82.10.0 0.0.0.255 area 2 ! ! line con 0 line aux 0 line vty 0 4 login ! end cisco3#
Neste ítem serão mostrados dois comandos que são fundamentais para
que possamos tirar nossas conclusões.
São eles: show ip route e traceroute.
O primeiro nos mostra por qual interface e por qual protocolo o roteador
aprende as outras redes, já o segundo nos mostra os roteadores percorridos
até o endereço de destino.
4000
<4000>#
<4000>#show ip route
Codes: C - connected, S - static, I - IGRP, 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, E - EGP
i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, * - candidate default
U - per-user static route, o - ODR
Gateway of last resort is 192.80.209.13 to network 0.0.0.0
C 192.80.209.0/24 is directly connected, Serial1
O IA 200.20.4.0/24 [110/138] via 192.80.209.13, 00:02:25, Serial1
C 200.20.6.0/24 is directly connected, Loopback0
139.82.0.0/32 is subnetted, 1 subnets
O IA 139.82.10.1 [110/138] via 192.80.209.13, 00:02:25, Serial1
200.20.3.0/32 is subnetted, 1 subnets
O IA 200.20.3.1 [110/75] via 192.80.209.13, 00:02:25, Serial1
C 192.80.100.0/24 is directly connected, Ethernet0
200.156.10.0/32 is subnetted, 1 subnets
O 200.156.10.1 [110/65] via 192.80.209.13, 00:02:25, Serial1
O IA 200.20.94.0/24 [110/74] via 192.80.209.13, 00:02:25, Serial1
Verificamos que o roteador 4000 aprende as outras redes por OSPF
através da interface Serial1, via 192.80.209.13 (interface Serial0
do cisco1).
É importante notar que as redes que possuem ao lado IA: 200.20.4.0 , 139.82.10.1 ,
200.20.3.1 e 200.20.94.0 fazem parte de áreas diferentes, por isso o nome de inter-área.
<4000>#
<4000>#traceroute 139.82.10.1
Type escape sequence to abort.
Tracing the route to 139.82.10.1
1 192.80.209.13 4 msec 0 msec 0 msec
2 200.20.94.1 8 msec 4 msec 4 msec
3 200.20.4.2 8 msec 4 msec *
<4000>#
Com o comando traceroute, confirmamos o caminho que o pacote percorre
até a interface 139.82.10.1 (Loopback0 do cisco3).
cisco1
cisco1#
cisco1#show ip route
Codes: C - connected, S - static, I - IGRP, 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, E - EGP
i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, * - candidate default
U - per-user static route, o - ODR
Gateway of last resort is not set
C 192.80.209.0/24 is directly connected, Serial0
C 200.156.10.0/24 is directly connected, Loopback0
C 200.20.94.0/24 is directly connected, Ethernet0
O IA 200.20.4.0/24 [110/74] via 200.20.94.1, 00:00:36, Ethernet0
139.82.0.0/32 is subnetted, 1 subnets
O IA 139.82.10.1 [110/74] via 200.20.94.1, 00:00:36, Ethernet0
200.20.6.0/32 is subnetted, 1 subnets
O 200.20.6.1 [110/65] via 192.80.209.14, 00:00:36, Serial0
200.20.3.0/32 is subnetted, 1 subnets
O IA 200.20.3.1 [110/11] via 200.20.94.1, 00:00:36, Ethernet0
O 192.80.100.0/24 [110/74] via 192.80.209.14, 00:00:36, Serial0
Verificamos que o roteador cisco1 aprende as outras redes por OSPF através de suas interfaces Serial0,
via 192.80.209.14 (Serial1 4000) e Ethernet0 via 200.20.94.1 (Ethernet0 cisco2).
É importante notar que as redes que possuem ao lado IA: 200.20.4.0 , 139.82.10.1 , 200.20.3.1
fazem parte de áreas diferentes, por isso o nome de inter-área.
cisco1#
cisco1#traceroute 139.82.10.1
Type escape sequence to abort.
Tracing the route to 139.82.10.1
1 200.20.94.1 4 msec 4 msec 4 msec
2 200.20.4.2 8 msec * 4 msec
cisco1#traceroute 192.80.100.5
Type escape sequence to abort.
Tracing the route to 192.80.100.5
1 192.80.209.14 0 msec 4 msec 4 msec
2 192.80.100.5 4 msec 4 msec 4 msec
cisco1#
Com o comando traceroute confirmamos o caminho que o pacote percorre
até a 139.82.10.1 (Loopback0 do cisco3) e até o PC 192.80.100.5.
cisco2
cisco2#
cisco2#show ip route
Codes: C - connected, S - static, I - IGRP, 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, E - EGP
i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, * - candidate default
U - per-user static route, o - ODR
Gateway of last resort is not set
O IA 192.80.209.0/24 [110/74] via 200.20.94.81, 00:00:03, Ethernet0
200.156.10.0/32 is subnetted, 1 subnets
O IA 200.156.10.1 [110/11] via 200.20.94.81, 00:00:03, Ethernet0
C 200.20.94.0/24 is directly connected, Ethernet0
C 200.20.4.0/24 is directly connected, Serial1
139.82.0.0/32 is subnetted, 1 subnets
O 139.82.10.1 [110/64] via 200.20.4.2, 00:00:03, Serial1
200.20.6.0/32 is subnetted, 1 subnets
O IA 200.20.6.1 [110/75] via 200.20.94.81, 00:00:03, Ethernet0
C 200.20.3.0/24 is directly connected, Loopback0
O IA 192.80.100.0/24 [110/84] via 200.20.94.81, 00:00:03, Ethernet0
Verificamos que o roteador cisco2 aprende as outras redes por OSPF através de suas interfaces Serial1,
via 200.20.4.2 (Serial1 cisco3) e Ethernet0 via 200.20.94.81 (Ethernet0 cisco1).
É importante notar que as redes que possuem ao lado IA: 192.80.209 , 200.156.10.1 ,
200.20.6.1 e 192.80.100.0 fazem parte de áreas diferentes, por isso o nome de inter-área.
cisco2#
cisco2#traceroute 192.80.100.5
Type escape sequence to abort.
Tracing the route to 192.80.100.5
1 200.20.94.81 4 msec 4 msec 4 msec
2 192.80.209.14 4 msec 4 msec 4 msec
3 192.80.100.5 4 msec 4 msec 8 msec
cisco2#
cisco2#traceroute 139.82.10.1
Type escape sequence to abort.
Tracing the route to 139.82.10.1
1 200.20.4.2 4 msec * 4 msec
cisco2#
Com o comando traceroute confirmamos o caminho que o pacote percorre
até a 139.82.10.19 (Loopback0 do cisco3) e até o PC 192.80.100.5.
cisco3
cisco3#
cisco3#show ip route
Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, * - candidate default
Gateway of last resort is not set
O IA 192.80.209.0 [110/1636] via 200.20.4.1, 00:09:38, Serial1
200.156.10.0 is subnetted (mask is 255.255.255.255), 1 subnets
O IA 200.156.10.1 [110/1573] via 200.20.4.1, 00:09:38, Serial1
O IA 200.20.94.0 [110/1572] via 200.20.4.1, 16:21:34, Serial1
C 200.20.4.0 is directly connected, Serial1
139.82.0.0 is subnetted (mask is 255.255.255.0), 1 subnets
C 139.82.10.0 is directly connected, Loopback0
200.20.6.0 is subnetted (mask is 255.255.255.255), 1 subnets
O IA 200.20.6.1 [110/1637] via 200.20.4.1, 00:09:39, Serial1
200.20.3.0 is subnetted (mask is 255.255.255.255), 1 subnets
O 200.20.3.1 [110/1563] via 200.20.4.1, 16:21:34, Serial1
O IA 192.80.100.0 [110/1646] via 200.20.4.1, 00:09:39, Serial1
Verificamos que o roteador cisco3 aprende as outras redes por OSPF através da interface Serial1,
via 200.20.4.1 (interface Serial1 do cisco2).
É importante notar que as redes que possuem ao lado IA: 192.80.209.0 , 200.56.10.1 ,
200.20.4.0 , 200.20.6.1 , 192.80.100.0 fazem parte de áreas diferentes,
por isso o nome de inter-área.
cisco3#
cisco3#trace ip 192.80.100.5
Type escape sequence to abort.
Tracing the route to 192.80.100.5
1 200.20.4.1 4 msec 4 msec 4 msec
2 200.20.94.81 4 msec 4 msec 4 msec
3 192.80.209.14 8 msec 4 msec 4 msec
4 192.80.100.5 8 msec 8 msec 4 msec
cisco3#
Com o comando traceroute confirmamos o caminho que o pacote percorre
até o PC 192.80.100.5.
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