Escenario de práctica de subnetting
Fecha: 3 de diciembre del 2014 Clase: Discovey 2 de becas Empleartec (con RIP v2)
Clase: in company, empresa #########
Escenario
Este escenario ya es un viejo conocido entre mis alumnos, es el escenario típico para el cálculo de
máscaras de subred y en esta oportunidad implementamos EIGRP como protocolo interior y BGP
para alcanzar internet mediante el AS 100.
Recordemos que Discovery 2 está orientado a formar profesionales para pequeños ISP, por lo tanto es
recurrente utilizar BGP, aunque vayamos mas allá de la currícula. En clase como IGP se utilizó RIP v2.
Cálculo de máscaras
Estimamos cantidad de usuarios
reales posibles
Rosario: 500 512 es un /23
Casilda: 200 256 /24
Firmat: 100 128 /25
Mendoza: 60 64 /26
Tucumán: 20 32 /27
San Juan: 10 14/28
Podrían estimarse máscaras menores para permitir escalabilidad pero no es el objetivo del escenario.
Rosario:
8 bits 256-2 254 -> 9 bits: 512-2=510 hosts -> 32-9=23 bits de máscara
180.64.0.0/23 ó 255.255.254.0, por lo tanto los host quedan:
180.64.0.1 hasta 180.64.1.254 (255 es broadcast)
Casilda:
180.64.2.0, -> 8 bits: 256-2=254 hosts -> /24 , por lo tanto los host quedan:
180.64.2.1 hasta 180.64.2.254 (255 es broadcast)
Firmat:
180.64.3.0 /25 o 255.255.255.128
180.64.3.1 a 180.64.3.126 (127 es broadcast)
Mendoza:
180.64.3.128 /26 0 255.255.255.192
180.64.3.129 a 180.64.3.190 (191 es broadcast)
Tucuman:
180.64.3.192 /27 o 255.255.255.224
180.64.3.193 a .222 (223 es broadcast)
San Juan: esta localidad se agregó luego, por lo tanto no está en un rango contiguo para demostrar
que VLSM no necesita tener continuidad si o si, sólo hay que respetar los rangos.
180.64.3.240 /28 o 255.255.255.240
180.64.3.241 a .254 (255 es broadcast)
Verificación: (sólo los sitios mas relevantes)
Internet#sh ip route (rutas EIGRP aprendidas por BGP)
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, ia - IS-IS inter area
* - candidate default, U - per-user static route, o - ODR
P - periodic downloaded static route
Gateway of last resort is 0.0.0.0 to network 0.0.0.0
10.0.0.0/8 is variably subnetted, 7 subnets, 2 masks
B 10.64.3.224/29 [20/28160] via 200.0.0.1, 01:00:06
B 10.64.3.232/30 [20/2172416] via 200.0.0.1, 01:00:06
B 10.64.3.236/30 [20/2172416] via 200.0.0.1, 01:00:06
B 10.64.3.240/30 [20/2169856] via 200.0.0.1, 01:00:06
B 10.64.3.244/30 [20/2169856] via 200.0.0.1, 01:00:06
B 10.64.3.248/30 [20/2172416] via 200.0.0.1, 01:00:06
B 10.64.3.252/30 [20/2172416] via 200.0.0.1, 01:00:06
64.0.0.0/29 is subnetted, 1 subnets
C 64.1.2.0 is directly connected, FastEthernet0/1
180.64.0.0/16 is variably subnetted, 7 subnets, 7 masks
B 180.64.0.0/23 [20/30720] via 200.0.0.1, 01:00:06
B 180.64.2.0/24 [20/30720] via 200.0.0.1, 01:00:06
B 180.64.3.0/25 [20/30720] via 200.0.0.1, 01:00:06
B 180.64.3.128/26 [20/30720] via 200.0.0.1, 01:00:06
B 180.64.3.192/27 [20/30720] via 200.0.0.1, 01:00:06
B 180.64.3.236/30 [20/2172416] via 200.0.0.1, 01:00:06
B 180.64.3.240/28 [20/284160] via 200.0.0.1, 01:00:06
200.0.0.0/30 is subnetted, 1 subnets
C 200.0.0.0 is directly connected, FastEthernet0/0
S* 0.0.0.0/0 is directly connected, Null0 (ruta por defecto para pruebas de redistribución)
Internet#
Borde#sh ip route (rutas interiores EIGRP y ruta por defecto aprendida por BGP)
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, ia - IS-IS inter area
* - candidate default, U - per-user static route, o - ODR
P - periodic downloaded static route
Gateway of last resort is 200.0.0.2 to network 0.0.0.0
* 0.0.0.0/32 is subnetted, 1 subnets
B* 0.0.0.0 [20/0] via 200.0.0.2, 01:02:00
10.0.0.0/8 is variably subnetted, 7 subnets, 2 masks
C 10.64.3.224/29 is directly connected, FastEthernet0/1
D 10.64.3.232/30 [90/2172416] via 10.64.3.225, 01:00:46, FastEthernet0/1
[90/2172416] via 10.64.3.228, 01:00:46, FastEthernet0/1
D 10.64.3.236/30 [90/2172416] via 10.64.3.228, 01:00:46, FastEthernet0/1
C 10.64.3.240/30 is directly connected, Serial0/0/0
C 10.64.3.244/30 is directly connected, Serial0/0/1
D 10.64.3.248/30 [90/2172416] via 10.64.3.227, 01:00:40, FastEthernet0/1
[90/2172416] via 10.64.3.226, 01:00:33, FastEthernet0/1
D 10.64.3.252/30 [90/2172416] via 10.64.3.225, 01:00:46, FastEthernet0/1
[90/2172416] via 10.64.3.226, 01:00:33, FastEthernet0/1
180.64.0.0/16 is variably subnetted, 7 subnets, 7 masks
D 180.64.0.0/23 [90/30720] via 10.64.3.225, 01:00:46, FastEthernet0/1
D 180.64.2.0/24 [90/30720] via 10.64.3.226, 01:00:33, FastEthernet0/1
D 180.64.3.0/25 [90/30720] via 10.64.3.227, 01:00:40, FastEthernet0/1
D 180.64.3.128/26 [90/30720] via 10.64.3.228, 01:00:46, FastEthernet0/1
D 180.64.3.192/27 [90/30720] via 10.64.3.229, 01:00:46, FastEthernet0/1
D 180.64.3.236/30 [90/2172416] via 10.64.3.229, 01:00:46, FastEthernet0/1
D 180.64.3.240/28 [90/284160] via 10.64.3.228, 01:00:46, FastEthernet0/1
200.0.0.0/30 is subnetted, 1 subnets
C 200.0.0.0 is directly connected, FastEthernet0/0
S* 0.0.0.0/0 [1/0] via 200.0.0.2
Borde#
Rosario#sh ip route (rutas EIGRP y ruta por defecto BGP redistribuida por EIGRP en Borde, ver AD de 170)
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, ia - IS-IS inter area
* - candidate default, U - per-user static route, o - ODR
P - periodic downloaded static route
Gateway of last resort is 10.64.3.230 to network 0.0.0.0
10.0.0.0/8 is variably subnetted, 7 subnets, 2 masks
C 10.64.3.224/29 is directly connected, FastEthernet0/1
C 10.64.3.232/30 is directly connected, Serial0/0/1
D 10.64.3.236/30 [90/2172416] via 10.64.3.228, 01:05:04, FastEthernet0/1
D 10.64.3.240/30 [90/2172416] via 10.64.3.229, 01:04:54, FastEthernet0/1
[90/2172416] via 10.64.3.230, 01:04:48, FastEthernet0/1
D 10.64.3.244/30 [90/2172416] via 10.64.3.230, 01:04:48, FastEthernet0/1
[90/2172416] via 10.64.3.227, 01:04:42, FastEthernet0/1
D 10.64.3.248/30 [90/2172416] via 10.64.3.227, 01:04:42, FastEthernet0/1
[90/2172416] via 10.64.3.226, 01:04:34, FastEthernet0/1
C 10.64.3.252/30 is directly connected, Serial0/0/0
180.64.0.0/16 is variably subnetted, 7 subnets, 7 masks
C 180.64.0.0/23 is directly connected, FastEthernet0/0
D 180.64.2.0/24 [90/30720] via 10.64.3.226, 01:04:34, FastEthernet0/1
D 180.64.3.0/25 [90/30720] via 10.64.3.227, 01:04:42, FastEthernet0/1
D 180.64.3.128/26 [90/30720] via 10.64.3.228, 01:05:04, FastEthernet0/1
D 180.64.3.192/27 [90/30720] via 10.64.3.229, 01:04:54, FastEthernet0/1
D 180.64.3.236/30 [90/2172416] via 10.64.3.229, 01:04:54, FastEthernet0/1
D 180.64.3.240/28 [90/284160] via 10.64.3.228, 01:05:04, FastEthernet0/1
D*EX 0.0.0.0/0 [170/53760] via 10.64.3.230, 00:30:38, FastEthernet0/1
Rosario#
Test de redundancia de rutas:
PC>tracert 64.1.2.3
Tracing route to 64.1.2.3 over a maximum of 30 hops:
1 0 ms 0 ms 0 ms 180.64.0.1
2 1 ms 0 ms 0 ms 10.64.3.230 (vía SW de Core)
3 0 ms 0 ms 0 ms 200.0.0.2
4 0 ms 0 ms 0 ms 64.1.2.3
Trace complete.
Inicialmente se corta el enlace Core -> Borde
PC>tracert 64.1.2.3
Tracing route to 64.1.2.3 over a maximum of 30 hops:
1 1 ms 0 ms 0 ms 180.64.0.1
2 0 ms 0 ms 0 ms 10.64.3.227 (vía Firmat porque atraviesa sólo un enlace serie)
3 1 ms 0 ms 0 ms 10.64.3.242
4 1 ms 1 ms 1 ms 200.0.0.2
5 0 ms 0 ms 1 ms 64.1.2.3
Trace complete.
Se elimina el link .227
PC>tracert 64.1.2.3
Tracing route to 64.1.2.3 over a maximum of 30 hops:
1 0 ms 0 ms 0 ms 180.64.0.1
2 0 ms 0 ms 0 ms 10.64.3.229 (vía Tucumán porque atraviesa sólo un enlace serie)
3 0 ms 1 ms 0 ms 10.64.3.242
4 1 ms 1 ms 1 ms 200.0.0.2
5 1 ms 0 ms 1 ms 64.1.2.3
Trace complete.
Se elimina el link .229
PC>tracert 64.1.2.3
Tracing route to 64.1.2.3 over a maximum of 30 hops:
1 0 ms 0 ms 0 ms 180.64.0.1
2 0 ms 0 ms 0 ms 10.64.3.226
3 1 ms 1 ms 0 ms 10.64.3.249
4 1 ms 0 ms 3 ms 10.64.3.245
5 1 ms 0 ms 2 ms 200.0.0.2
6 0 ms 1 ms 0 ms 64.1.2.3
Trace complete.
Se elimina el link .226
PC>tracert 64.1.2.3
Tracing route to 64.1.2.3 over a maximum of 30 hops:
1 1 ms 1 ms 0 ms 180.64.0.1
2 3 ms 0 ms 0 ms 10.64.3.228
3 1 ms 1 ms 3 ms 10.64.3.238
4 1 ms 2 ms 2 ms 10.64.3.242
5 0 ms 2 ms 1 ms 200.0.0.2
6 0 ms 2 ms 0 ms 64.1.2.3
Trace complete.
Se elimina el link .228
PC>tracert 64.1.2.3
Tracing route to 64.1.2.3 over a maximum of 30 hops:
1 1 ms 0 ms 0 ms 180.64.0.1
2 * 1 ms 2 ms 10.64.3.253
3 3 ms 0 ms 1 ms 10.64.3.238
4 3 ms 6 ms 2 ms 10.64.3.245
5 5 ms 2 ms 3 ms 200.0.0.2
6 1 ms 4 ms 3 ms 64.1.2.3
Trace complete.
Se elimina el link .238
PC>tracert 64.1.2.3
Tracing route to 64.1.2.3 over a maximum of 30 hops:
1 0 ms 0 ms 0 ms 180.64.0.1
2 1 ms 1 ms 1 ms 10.64.3.234
3 1 ms 1 ms 1 ms 10.64.3.238
4 5 ms 4 ms 2 ms 10.64.3.242
5 6 ms 2 ms 1 ms 200.0.0.2
6 1 ms 1 ms 2 ms 64.1.2.3
Trace complete.
La peor condición:
PC>tracert 64.1.2.3
Tracing route to 64.1.2.3 over a maximum of 30 hops:
1 0 ms 0 ms 0 ms 180.64.0.1
2 * 1 ms 1 ms 10.64.3.253
3 1 ms 1 ms 1 ms 10.64.3.249
4 4 ms 1 ms 2 ms 10.64.3.228
5 5 ms 2 ms 5 ms 10.64.3.242
6 * 2 ms 6 ms 200.0.0.2
7 2 ms 1 ms 9 ms 64.1.2.3
Trace complete.
Configuración de equipos: (sólo los mas relevantes)
Borde#sh runn
Building configuration...
Current configuration : 934 bytes
!
version 12.4
!
hostname Borde
!
interface FastEthernet0/0
ip address 200.0.0.1 255.255.255.252
!
interface FastEthernet0/1
ip address 10.64.3.230 255.255.255.248
!
interface Serial0/0/0
ip address 10.64.3.242 255.255.255.252
!
interface Serial0/0/1
ip address 10.64.3.245 255.255.255.252
!
router eigrp 100
redistribute bgp 100
redistribute static
network 10.0.0.0 (para los enlaces WAN y core)
no auto-summary
!
router bgp 100
bgp log-neighbor-changes
no synchronization
neighbor 200.0.0.2 remote-as 200
redistribute eigrp 100
!
ip classless
ip route 0.0.0.0 0.0.0.0 200.0.0.2
!
end
Borde#
Internet#sh runn
Building configuration...
Current configuration : 667 bytes
!
version 12.4
!
hostname Internet
!
interface FastEthernet0/0
ip address 200.0.0.2 255.255.255.252
!
interface FastEthernet0/1
ip address 64.1.2.1 255.255.255.248
!
router bgp 200
bgp log-neighbor-changes
no synchronization
neighbor 200.0.0.1 remote-as 100
redistribute static
!
ip classless
ip route 0.0.0.0 0.0.0.0 Null0
!
end
Internet#
Rosario#sh runn
Building configuration...
Current configuration : 732 bytes
!
version 12.4
!
hostname Rosario
!
interface FastEthernet0/0
ip address 180.64.0.1 255.255.254.0
!
interface FastEthernet0/1
ip address 10.64.3.225 255.255.255.248
!
interface Serial0/0/0
ip address 10.64.3.254 255.255.255.252
!
interface Serial0/0/1
ip address 10.64.3.233 255.255.255.252
!
router eigrp 100
network 180.64.0.0 0.0.1.255 (publica segmento de 500 usuarios)
network 10.0.0.0 (para los enlaces WAN y core)
no auto-summary
!
end
Rosario#
Redistribución en EIGRP de la ruta por defecto aprendida por BGP
Estos comandos no están soportados en Packet Tracert, se utiliza un route-map que asocia una lista de prefijos,
en este caso existe sólo la ruta por defecto, las métricas de la redistribución no están calculadas sino estimadas.
Router Borde:
(2014) What is the next hop to reach the route 66 ?
Rosario, Argentina