Pruebas de sumarización
de OSPF en un escenario multiárea
Fecha: 14 de julio del
2014 Clase: particular para rendir el exámen
R&S
Escenario
En este escenario se intenta verificar la sumarización de rutas en OSPF en un ambiente multiárea, donde con otros
protocolos esto se realizaría de forma
automática (aunque tampoco forzada con un prefijo óptimo en caso de EIGRP).
Recordemos que por
defecto, OSPF no sumariza rutas y se puede realizar
manualmente.
El router CasaCentral se comporta como ABR (Area
Border Router), este
escenario se realizó con equipos reales,
Packet Tracert
no soporta el comando de sumarizar las rutas en OSPF.
Verficación en Casa Central:
CasaCentral#sh 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, 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
10.0.0.0/30 is subnetted, 1 subnets
C 10.0.0.0 is directly connected, FastEthernet0/1
C 192.168.1.0/24 is directly connected, FastEthernet0/0.1
C 192.168.2.0/24 is directly connected, FastEthernet0/0.2
C 192.168.3.0/24 is directly connected, FastEthernet0/0.3
C 192.168.4.0/24 is directly connected, FastEthernet0/0.4
C 192.168.5.0/24 is directly connected, FastEthernet0/0.5
C 192.168.6.0/24 is directly connected, FastEthernet0/0.6
C 192.168.7.0/24 is directly connected, FastEthernet0/0.7
CasaCentral#
Verificación en Sucursal:
Sucursal#sh 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, 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
O IA 192.168.4.0/24 [110/11] via 10.0.0.1, 00:08:55, Ethernet0/0
O IA 192.168.5.0/24 [110/11] via 10.0.0.1, 00:08:55, Ethernet0/0
10.0.0.0/30 is subnetted, 1 subnets
C 10.0.0.0 is directly connected, Ethernet0/0
O IA 192.168.6.0/24 [110/11] via 10.0.0.1, 00:08:55, Ethernet0/0
O IA 192.168.7.0/24 [110/11] via 10.0.0.1, 00:08:55, Ethernet0/0
O IA 192.168.1.0/24 [110/11] via 10.0.0.1, 00:08:55, Ethernet0/0
O IA 192.168.2.0/24 [110/11] via 10.0.0.1, 00:08:55, Ethernet0/0
O IA 192.168.3.0/24 [110/11] via 10.0.0.1, 00:08:56, Ethernet0/0
Sucursal#
CasaCentral (config)#router
ospf 1 (sumariza manualmente las rutas, este comando difiere a
EIGRP, que lo
CasaCentral(config-router)#area 1 range 192.168.0.0
255.255.248.0
realiza dentro de la interface)
CasaCentral(config-router)#^Z
CasaCentral#
Sucursal#sh ip route (verificación)
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 not set
10.0.0.0/30 is subnetted, 1 subnets
C 10.0.0.0 is directly connected, Ethernet0/0
O IA 192.168.0.0/21 [110/11] via 10.0.0.1, 00:00:37, Ethernet0/0
Sucursal#
Lectura recomendada:
http://www.cisco.com/c/en/us/support/docs/ip/open-shortest-path-first-ospf/7039-1.html#t29
Rollback de la sumarización:
CasaCentral(config)#router
ospf 1
CasaCentral(config-router)#no area 1 range 192.168.0.0 255.255.248.0
CasaCentral(config-router)#^Z
CasaCentral#
Sucursal#sh ip route (verificación)
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 not set
O IA 192.168.4.0/24 [110/11] via 10.0.0.1, 00:00:02, Ethernet0/0
O IA 192.168.5.0/24 [110/11] via 10.0.0.1, 00:00:02, Ethernet0/0
10.0.0.0/30 is subnetted, 1 subnets
C 10.0.0.0 is directly connected, Ethernet0/0
O IA 192.168.6.0/24 [110/11] via 10.0.0.1, 00:00:02, Ethernet0/0
O IA 192.168.7.0/24 [110/11] via 10.0.0.1, 00:00:02, Ethernet0/0
O IA 192.168.1.0/24 [110/11] via 10.0.0.1, 00:00:02, Ethernet0/0
O IA 192.168.2.0/24 [110/11] via 10.0.0.1, 00:00:02, Ethernet0/0
O IA 192.168.3.0/24 [110/11] via 10.0.0.1, 00:00:03, Ethernet0/0
Sucursal#
Captura de los paquetes sin sumarizar (pero son LSA summary type 3):
Frame 30: 258 bytes on wire (2064 bits), 258 bytes captured (2064 bits) on interface 0
Ethernet II, Src: 00:18:ba:d1:1f:91, Dst: 01:00:5e:00:00:05
Internet Protocol Version 4, Src: 10.0.0.1 (10.0.0.1), Dst: 224.0.0.5 (224.0.0.5)
Open Shortest Path First
OSPF Header
LS Update Packet
Number of LSAs: 7
LS Type: Summary-LSA (IP network)
LS Age: 3600 seconds
Do Not Age: False
Options: 0x22 (DC, E)
Link-State Advertisement Type: Summary-LSA (IP network) (3)
Link State ID: 192.168.7.0
Advertising Router: 192.168.254.254 (192.168.254.254)
LS Sequence Number: 0x80000002
LS Checksum: 0x89da
Length: 28
Netmask: 255.255.255.0
Metric: 16777215
LS Type: Summary-LSA (IP network)
LS Age: 3600 seconds
Do Not Age: False
Options: 0x22 (DC, E)
Link-State Advertisement Type: Summary-LSA (IP network) (3)
Link State ID: 192.168.6.0
Advertising Router: 192.168.254.254 (192.168.254.254)
LS Sequence Number: 0x80000002
LS Checksum: 0x94d0
Length: 28
Netmask: 255.255.255.0
Metric: 16777215
LS Type: Summary-LSA (IP network)
LS Age: 3600 seconds
Do Not Age: False
Options: 0x22 (DC, E)
Link-State Advertisement Type: Summary-LSA (IP network) (3)
Link State ID: 192.168.5.0
Advertising Router: 192.168.254.254 (192.168.254.254)
LS Sequence Number: 0x80000002
LS Checksum: 0x9fc6
Length: 28
Netmask: 255.255.255.0
Metric: 16777215
LS Type: Summary-LSA (IP network)
LS Age: 3600 seconds
Do Not Age: False
Options: 0x22 (DC, E)
Link-State Advertisement Type: Summary-LSA (IP network) (3)
Link State ID: 192.168.4.0
Advertising Router: 192.168.254.254 (192.168.254.254)
LS Sequence Number: 0x80000002
LS Checksum: 0xaabc
Length: 28
Netmask: 255.255.255.0
Metric: 16777215
LS Type: Summary-LSA (IP network)
LS Age: 3600 seconds
Do Not Age: False
Options: 0x22 (DC, E)
Link-State Advertisement Type: Summary-LSA (IP network) (3)
Link State ID: 192.168.3.0
Advertising Router: 192.168.254.254 (192.168.254.254)
LS Sequence Number: 0x80000002
LS Checksum: 0xb5b2
Length: 28
Netmask: 255.255.255.0
Metric: 16777215
LS Type: Summary-LSA (IP network)
LS Age: 3600 seconds
Do Not Age: False
Options: 0x22 (DC, E)
Link-State Advertisement Type: Summary-LSA (IP network) (3)
Link State ID: 192.168.2.0
Advertising Router: 192.168.254.254 (192.168.254.254)
LS Sequence Number: 0x80000002
LS Checksum: 0xc0a8
Length: 28
Netmask: 255.255.255.0
Metric: 16777215
LS Type: Summary-LSA (IP network)
LS Age: 3600 seconds
Do Not Age: False
Options: 0x22 (DC, E)
Link-State Advertisement Type: Summary-LSA (IP network) (3)
Link State ID: 192.168.1.0
Advertising Router: 192.168.254.254 (192.168.254.254)
LS Sequence Number: 0x80000002
LS Checksum: 0xcb9e
Length: 28
Netmask: 255.255.255.0
Metric: 16777215
Captura de la trama sumarizada:
Frame 29: 90 bytes on wire (720 bits), 90 bytes
Ethernet II, Src: 00:18:ba:d1:1f:91 ,Dst: 01:00:5e:00:00:05
Internet Protocol Version 4, Src: 10.0.0.1 (10.0.0.1), Dst: 224.0.0.5 (224.0.0.5)
Open Shortest Path First
OSPF Header
LS Update Packet
Number of LSAs: 1
LS Type: Summary-LSA (IP network)
LS Age: 1 seconds
Do Not Age: False
Options: 0x22 (DC, E)
0... .... = DN: DN-bit is NOT set
.0.. .... = O: O-bit is NOT set
..1. .... = DC: Demand Circuits are supported
...0 .... = L: The packet does NOT contain LLS data block
.... 0... = NP: NSSA is NOT supported
.... .0.. = MC: NOT Multicast Capable
.... ..1. = E: External Routing Capability
.... ...0 = MT: NO Multi-Topology Routing
Link-State Advertisement Type: Summary-LSA (IP network) (3)
Link State ID: 192.168.0.0
Advertising Router: 192.168.254.254 (192.168.254.254)
LS Sequence Number: 0x80000001
LS Checksum: 0xbfb2
Length: 28
Netmask: 255.255.248.0
Metric: 1
(2014) Networking may cause synesthesia
Rosario, Argentina