We live in a society exquisitely dependent on science and technology, in which hardly anyone knows anything about science and technology.Vivimos en una sociedad exquisitamente dependiente de la tecnología, en la cual difícilmente alguien sabe algo de ciencia y tecnología.
Carl Sagan
lunes, 23 de agosto de 2010
cita
Review Questions EIGRP y OSPF
1. Your company is running IGRP using an AS of 10. You want to configure EIGRP on the network but want to migrate slowly to EIGRP and don’t want to configure redistribution. What command would allow you to migrate over time to EIGRP without configuring redistribution?
A. router eigrp 11
B. router eigrp 10
C. router eigrp 10 redistribute igrp
D. router igrp combine eigrp 10
2. Which EIGRP information is held in RAM and maintained through the use of Hello and update packets? (Choose two.)
A. Neighbor table
B. STP table
C. Topology table
D. DUAL table
3. Which of the following describe the process identifier that is used to run OSPF on a router?
(Choose two.)
A. It is locally significant.
B. It is globally significant.
C. It is needed to identify a unique instance of an OSPF database.
D. It is an optional parameter required only if multiple OSPF processes are running on the router.
E. All routes in the same OSPF area must have the same Process ID if they are to exchange routing information.
4. Where are EIGRP successor routes stored?
A. In the routing table only
B. In the neighbor table only
C. In the topology table only
D. In the routing table and neighbor table
E. In the routing table and the topology table
F. In the topology table and the neighbor table
5. Which command will display all the EIGRP feasible successor routes known to a router?
A. show ip routes *
B. show ip eigrp summary
C. show ip eigrp topology
D. show ip eigrp adjacencies
E. show ip eigrp neighbors detail
6. You get a call from a network administrator who tells you that he typed the following into his router:
Router(config)#router ospf 1
Router(config-router)#network 10.0.0.0 255.0.0.0 area 0
He tells you he still can’t see any routes in the routing table. What configuration error did the administrator make?
A. The wildcard mask is incorrect.
B. The OSPF area is wrong.
C. The OSPF Process ID is incorrect.
D. The AS configuration is wrong.
7. Which of the following protocols support VLSM, summarization, and discontiguous networking?
(Choose three.)
A. RIPv1
B. IGRP
C. EIGRP
D. OSPF
E. BGP
F. RIPv2
8. Which of the following are true regarding OSPF areas? (Choose three.)
A. You must have separate loopback interfaces configured in each area.
B. The numbers you can assign an area go up to 65,535.
C. The backbone area is also called area 0.
D. If your design is hierarchical, then you don’t need multiple areas.
E. All areas must connect to area 0.
F. If you have only one area, it must be called area 1.
9. Which of the following network types have a designated router and a backup designated router assigned? (Choose two.)
A. Broadcast
B. Point-to-point
C. NBMA
D. NBMA point-to-point
E. NBMA point-to-multipoint
10. A network administrator needs to configure a router with a distance-vector protocol that allows classless routing. Which of the following satisfies those requirements?
A. IGRP
B. OSPF
C. RIPv1
D. EIGRP
E. IS-IS
11. You need the IP address of the devices with which the router has established an adjacency.
Also, the retransmit interval and the queue counts for the adjacent routers need to be checked.
What command will display the required information?
A. show ip eigrp adjacency
B. show ip eigrp topology
C. show ip eigrp interfaces
D. show ip eigrp neighbors
12. For some reason, you cannot establish an adjacency relationship on a common Ethernet link between two routers. Looking at the output below, what is the cause of the problem?
A. The OSPF area is not configured properly.
B. The priority on RouterA should be set higher.
C. The cost on RouterA should be set higher.
D. The Hello and Dead timers are not configured properly.
E. A backup designated router needs to be added to the network.
F. The OSPF Process ID numbers must match.
13. Which is true regarding EIGRP successor routes? (Choose two.)
A. A successor route is used by EIGRP to forward traffic to a destination.
B. Successor routes are saved in the topology table to be used if the primary route fails.
C. Successor routes are flagged as “active” in the routing table.
D. A successor route may be backed up by a feasible successor route.
E. Successor routes are stored in the neighbor table following the discovery process.
14. Which type of OSPF network will elect a backup designated router? (Choose two.)
A. Broadcast multi-access
B. Non-broadcast multi-access
C. Point-to-point
D. Broadcast multipoint
15. Which two of the following commands will place network 10.2.3.0/24 into area 0? (Choose two.)
A. router eigrp 10
B. router ospf 10
C. router rip
D. network 10.0.0.0
E. network 10.2.3.0 255.255.255.0 area 0
F. network 10.2.3.0 0.0.0.255 area0
G. network 10.2.3.0 0.0.0.255 area 0
16. With which network type will OSPF establish router adjacencies but not perform the DR/BDR
election process?
A. Point-to-point
B. Backbone area 0
C. Broadcast multi-access
D. Non-broadcast multi-access
17. What are three reasons for creating OSPF in a hierarchical design? (Choose three.)
A. To decrease routing overhead
B. To speed up convergence
C. To confine network instability to single areas of the network
D. To make configuring OSPF easier
18. What is the administrative distance of OSPF?
A. 90
B. 100
C. 110
D. 120
19. You have an internetwork as shown in the following illustration. However, the two networks are not sharing routing table route entries. Which command is needed to fix the problem?
A. version 2
B. no auto-summary
C. redistribute eigrp 10
D. default-information originate
20. If routers in a single area are configured with the same priority value, what value does a router use for the OSPF Router ID in the absence of a loopback interface?
A. The lowest IP address of any physical interface
B. The highest IP address of any physical interface
C. The lowest IP address of any logical interface
D. The highest IP address of any logical interface
Respuestas.
A. router eigrp 11
B. router eigrp 10
C. router eigrp 10 redistribute igrp
D. router igrp combine eigrp 10
2. Which EIGRP information is held in RAM and maintained through the use of Hello and update packets? (Choose two.)
A. Neighbor table
B. STP table
C. Topology table
D. DUAL table
3. Which of the following describe the process identifier that is used to run OSPF on a router?
(Choose two.)
A. It is locally significant.
B. It is globally significant.
C. It is needed to identify a unique instance of an OSPF database.
D. It is an optional parameter required only if multiple OSPF processes are running on the router.
E. All routes in the same OSPF area must have the same Process ID if they are to exchange routing information.
4. Where are EIGRP successor routes stored?
A. In the routing table only
B. In the neighbor table only
C. In the topology table only
D. In the routing table and neighbor table
E. In the routing table and the topology table
F. In the topology table and the neighbor table
5. Which command will display all the EIGRP feasible successor routes known to a router?
A. show ip routes *
B. show ip eigrp summary
C. show ip eigrp topology
D. show ip eigrp adjacencies
E. show ip eigrp neighbors detail
6. You get a call from a network administrator who tells you that he typed the following into his router:
Router(config)#router ospf 1
Router(config-router)#network 10.0.0.0 255.0.0.0 area 0
He tells you he still can’t see any routes in the routing table. What configuration error did the administrator make?
A. The wildcard mask is incorrect.
B. The OSPF area is wrong.
C. The OSPF Process ID is incorrect.
D. The AS configuration is wrong.
7. Which of the following protocols support VLSM, summarization, and discontiguous networking?
(Choose three.)
A. RIPv1
B. IGRP
C. EIGRP
D. OSPF
E. BGP
F. RIPv2
8. Which of the following are true regarding OSPF areas? (Choose three.)
A. You must have separate loopback interfaces configured in each area.
B. The numbers you can assign an area go up to 65,535.
C. The backbone area is also called area 0.
D. If your design is hierarchical, then you don’t need multiple areas.
E. All areas must connect to area 0.
F. If you have only one area, it must be called area 1.
9. Which of the following network types have a designated router and a backup designated router assigned? (Choose two.)
A. Broadcast
B. Point-to-point
C. NBMA
D. NBMA point-to-point
E. NBMA point-to-multipoint
10. A network administrator needs to configure a router with a distance-vector protocol that allows classless routing. Which of the following satisfies those requirements?
A. IGRP
B. OSPF
C. RIPv1
D. EIGRP
E. IS-IS
11. You need the IP address of the devices with which the router has established an adjacency.
Also, the retransmit interval and the queue counts for the adjacent routers need to be checked.
What command will display the required information?
A. show ip eigrp adjacency
B. show ip eigrp topology
C. show ip eigrp interfaces
D. show ip eigrp neighbors
12. For some reason, you cannot establish an adjacency relationship on a common Ethernet link between two routers. Looking at the output below, what is the cause of the problem?
RouterA#
Ethernet0/0 is up, line protocol is up
Internet Address 172.16.1.2/16, Area 0
Process ID 2, Router ID 172.126.1.1, Network Type BROADCAST, Cost: 10
Transmit Delay is 1 sec, State DR, Priority 1
Designated Router (ID) 172.16.1.2, interface address 172.16.1.1
No backup designated router on this network Timer intervals configured, Hello 5, Dead 20, Wait 20, Retransmit 5
RouterB#
Ethernet0/0 is up, line protocol is up
Internet Address 172.16.1.1/16, Area 0
Process ID 2, Router ID 172.126.1.1, Network Type BROADCAST, Cost: 10
Transmit Delay is 1 sec, State DR, Priority 1
Designated Router (ID) 172.16.1.1, interface address 172.16.1.2
No backup designated router on this network
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
A. The OSPF area is not configured properly.
B. The priority on RouterA should be set higher.
C. The cost on RouterA should be set higher.
D. The Hello and Dead timers are not configured properly.
E. A backup designated router needs to be added to the network.
F. The OSPF Process ID numbers must match.
13. Which is true regarding EIGRP successor routes? (Choose two.)
A. A successor route is used by EIGRP to forward traffic to a destination.
B. Successor routes are saved in the topology table to be used if the primary route fails.
C. Successor routes are flagged as “active” in the routing table.
D. A successor route may be backed up by a feasible successor route.
E. Successor routes are stored in the neighbor table following the discovery process.
14. Which type of OSPF network will elect a backup designated router? (Choose two.)
A. Broadcast multi-access
B. Non-broadcast multi-access
C. Point-to-point
D. Broadcast multipoint
15. Which two of the following commands will place network 10.2.3.0/24 into area 0? (Choose two.)
A. router eigrp 10
B. router ospf 10
C. router rip
D. network 10.0.0.0
E. network 10.2.3.0 255.255.255.0 area 0
F. network 10.2.3.0 0.0.0.255 area0
G. network 10.2.3.0 0.0.0.255 area 0
16. With which network type will OSPF establish router adjacencies but not perform the DR/BDR
election process?
A. Point-to-point
B. Backbone area 0
C. Broadcast multi-access
D. Non-broadcast multi-access
17. What are three reasons for creating OSPF in a hierarchical design? (Choose three.)
A. To decrease routing overhead
B. To speed up convergence
C. To confine network instability to single areas of the network
D. To make configuring OSPF easier
18. What is the administrative distance of OSPF?
A. 90
B. 100
C. 110
D. 120
19. You have an internetwork as shown in the following illustration. However, the two networks are not sharing routing table route entries. Which command is needed to fix the problem?
A. version 2
B. no auto-summary
C. redistribute eigrp 10
D. default-information originate
20. If routers in a single area are configured with the same priority value, what value does a router use for the OSPF Router ID in the absence of a loopback interface?
A. The lowest IP address of any physical interface
B. The highest IP address of any physical interface
C. The lowest IP address of any logical interface
D. The highest IP address of any logical interface
Respuestas.
written lab de EIGRP y OSPF
- ¿Cuáles son los 4 protocolos ruteables soportados por EIGRP?
- ¿Cuándo es necesaria la redistribución en EIGRP?
- ¿Qué comando se usaría para activar EIGRP con un Sistema Autónomo de 300?
- ¿Qué comando le dice a EIGRP que está conectado a la red 172.10.0.0?
- ¿Qué tipo de interface de EIGRP no enviará o recibirá Hello Packets?
- Escriba el comando que activará el proceso 101 de OSPF en un router
- Escriba el comando que mostrará los detalles de todos los procesos de ruteo de OSPF
- Escriba el comando que mostrará información específica para una interface de OSPF
- Escriba el comando que mostrará todos los vecinos de OSPF
- Escriba el comando que mostrara todos los tipos de rutas que se conocen por OSPF en el router.
Respuestas.
domingo, 22 de agosto de 2010
Práctica de EIGRP y OSPF
En el capítulo 7 del Sybex para CCNA tenemos una práctica de laboratorio para EIGRP y OSPF que cubre la siguiente topología, y después un ejemplo de como se lleva a cabo la elección de un Designated Router cambiando las prioridades de los routers para forzar las decisiones hacia nuestro interés.
Ejemplo en Packet Tracer.
Para la primera topología:
TABLa 7 . 5 Esquema de direccionamiento IP
router Interface IP address
A F0/0 172.16.10.1
B E0 172.16.10.2
B S0 172.16.20.1
C E0 172.16.30.1
C S0 172.16.20.2
C S1 172.16.40.1
D S0 172.16.40.2
D E0 172.16.50.1
Ejemplo en Packet Tracer.
Para la primera topología:
TABLa 7 . 5 Esquema de direccionamiento IP
router Interface IP address
A F0/0 172.16.10.1
B E0 172.16.10.2
B S0 172.16.20.1
C E0 172.16.30.1
C S0 172.16.20.2
C S1 172.16.40.1
D S0 172.16.40.2
D E0 172.16.50.1
martes, 17 de agosto de 2010
Open Shortest Path First
El protocolo OSPF es un estándar que funciona en muchos fabricantes y es una opción cuando se debe rutear entre routers que usan diferentes sistemas operativos y no IOS; se basa en anuncios de estado del enlace, sólo envía actualizaciones cuando dicho estado cambia. Además, está basado en un número de AS y un área, algo que no había en EIGRP; para participar del esquema de ruteo no sólo hay que estar en el mismo sistema autónomo, sino en la misma área.
A diferencia de EIGRP, aquí no hay autosumarización y debe ser manual, usamos wildcards en lugar de máscaras de red, y se comparte la información de ruteo sólo entre los routers de la misma área, y un router puede estar en distintas áreas, según configuremos el protocolo, y podemos configurar también procesos de ruteo independientes.
Los paquetes hello, como en EIGRP se envían a una dirección de multicast (224.0.0.5), y se va construyendo una tabla de vecinos y una topológica de la cual con el algritmo de Dijkstra se calcula ruta más corta a otra red.
Se envían anuncios del estado del enlace sólo a aquellos routers con los que se forma una adjacencia, y se nombra un Designated Router cuando se trata de una red de "broadcast" (ethernet usualmente), no así cuando es una red basada en Frame Relay por ejemplo.
El área es un grupo de redes y routers que comparten el mismo Area ID, y todos los routers en el área tienen la misma tabla de topología; los anuncios se envían y reciben sólo desde el Designated Router, lo cual disminuye las adjacencias y evita que se duplique o deforme la información de la red; además las áreas nos permiten tener un diseño jerárquico.
La distancia administrativa por default es:
OSPF asigna un costo, que Cisco calcula como 10^8/Bandwidth, así que un link de 64Kbps tiene un costo de 1563.
Para el ejemplo de ruteo usaremos la topología de EIGRP que teníamos ya hecha y hacemos algunos cambios en cada router:
Descarga el ejemplo para Packet Tracer aquí
desactivamos el EIGRP
Corp(config)#no router eigrp 10
activamos el OSPF
Corp(config)#router ospf 100
Corp(config-router)#network 10.1.0.0 0.0.255.255 area 0
Y para verificarlo podemos usar los siguientes comandos:
A diferencia de EIGRP, aquí no hay autosumarización y debe ser manual, usamos wildcards en lugar de máscaras de red, y se comparte la información de ruteo sólo entre los routers de la misma área, y un router puede estar en distintas áreas, según configuremos el protocolo, y podemos configurar también procesos de ruteo independientes.
Los paquetes hello, como en EIGRP se envían a una dirección de multicast (224.0.0.5), y se va construyendo una tabla de vecinos y una topológica de la cual con el algritmo de Dijkstra se calcula ruta más corta a otra red.
Se envían anuncios del estado del enlace sólo a aquellos routers con los que se forma una adjacencia, y se nombra un Designated Router cuando se trata de una red de "broadcast" (ethernet usualmente), no así cuando es una red basada en Frame Relay por ejemplo.
El área es un grupo de redes y routers que comparten el mismo Area ID, y todos los routers en el área tienen la misma tabla de topología; los anuncios se envían y reciben sólo desde el Designated Router, lo cual disminuye las adjacencias y evita que se duplique o deforme la información de la red; además las áreas nos permiten tener un diseño jerárquico.
La distancia administrativa por default es:
- Interface conectada 0
- Ruta estática 1
- EIGRP 90
- IGRP 100
- OSPF 110
- RIP 120
- External EIGRP 170
- 255 para las rutas que no serán usadas.
OSPF asigna un costo, que Cisco calcula como 10^8/Bandwidth, así que un link de 64Kbps tiene un costo de 1563.
Para el ejemplo de ruteo usaremos la topología de EIGRP que teníamos ya hecha y hacemos algunos cambios en cada router:
Descarga el ejemplo para Packet Tracer aquí
desactivamos el EIGRP
Corp(config)#no router eigrp 10
activamos el OSPF
Corp(config)#router ospf 100
Corp(config-router)#network 10.1.0.0 0.0.255.255 area 0
Y para verificarlo podemos usar los siguientes comandos:
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