Escenario multi ISP para migrar enlaces a PPP

Fecha: 8 de septiembre del 2012, Clase: CCNA 4

En este escenario existen dos sucursales: Rosario y Córdoba, unidos por 4 ISP, los cuales existen dentro de la "nube", a la cual

no se puede acceder, por lo tanto, deberemos aplicar habilidades adquiridas en CCNA2.

Escenario disponible en: ftp://ftp.vilarrasa.com.ar/ (user y pass: ccna)

Para poder migrar los enlaces, debemos ingresar primero en una sucursal (en este ejemplo Rosario), luego "pararnos" en uno

de los ISP de la nube y de allí, en la sucursal remota (en este ejemplo Córdoba).

Una vez allí debemos comenzar a migrar desde HDLC (encapsulación por defecto) a PPP, siguiendo el sentido inverso hacia

Rosario, porque de lo contrario si migraramos primero nuestro extremo perdemos contacto con el extremo opuesto, y por lo

tanto no podremos cambiar de protocolo.

Si comenzamos en Rosario y tener que entrar en Córdoba vía la solapa CLI, significaría "un viajecito" en avión hasta allá y

tomar control del router (bien hecho y mas barato en remoto).

Si efectuaramos el procedimiento incorrecto, nos encontraríamos con esta situación:

Rosario#sh ip ospf nei(buscamos vecinos)

Neighbor ID Pri State Dead Time Address Interface

172.16.5.2 0 FULL/ - 00:00:30 172.16.1.2 Serial0/1

172.16.6.2 0 FULL/ - 00:00:32 172.16.2.2 Serial0/2

172.16.7.2 0 FULL/ - 00:00:39 172.16.3.2 Serial0/3

172.16.4.2 0 FULL/ - 00:00:32 172.16.0.2 Serial0/0 (elegimos un vecino)

Rosario#conf t

Enter configuration commands, one per line. End with CNTL/Z.

Rosario(config)#int s0/0

Rosario(config-if)#encapsulation ppp (el enlace se caerá)

%LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/0, changed state to down

00:00:37: %OSPF-5-ADJCHG: Process 1, Nbr 172.16.4.2 on Serial0/0 from FULL to DOWN,

Neighbor Down: Interface down or detached

Rosario(config-if)#exit

Rosario(config)#exit

%SYS-5-CONFIG_I: Configured from console by console

Rosario#telnet 172.16.0.2 (intentamos cambiar a PPP el extremo)

Trying 172.16.0.2 ...

% Connection timed out; remote host not responding

Rosario#sh ip ospf nei (no existe vecino en la Serial0/0)

Neighbor ID Pri State Dead Time Address Interface

172.16.5.2 0 FULL/ - 00:00:32 172.16.1.2 Serial0/1

172.16.6.2 0 FULL/ - 00:00:35 172.16.2.2 Serial0/2

172.16.7.2 0 FULL/ - 00:00:31 172.16.3.2 Serial0/3

Rosario#sh int s0/0 (verificamos capa 2 en la interfaz)

Serial0/0 is up, line protocol is down (disabled)

Hardware is HD64570

Internet address is 172.16.0.1/24

MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec,

reliability 255/255, txload 1/255, rxload 1/255

Encapsulation PPP, loopback not set, keepalive set (10 sec)

LCP Closed

Closed: LEXCP, BRIDGECP, IPCP, CCP, CDPCP, LLC2, BACP (protocolos L3 soportados por NCP)

Last input never, output never, output hang never

---resumido---

Detalle de la migración ( un solo ISP )

Verificación inicial

Rosario#sh ip osp nei (buscamos vecinos)

Neighbor ID Pri State Dead Time Address Interface

172.16.7.2 0 FULL/ - 00:00:30 172.16.3.2 Serial0/3 (elegimos uno, no confundir ID

172.16.5.2 0 FULL/ - 00:00:30 172.16.1.2 Serial0/1 con IP del router (Address))

172.16.4.2 0 FULL/ - 00:00:38 172.16.0.2 Serial0/0

172.16.6.2 0 FULL/ - 00:00:31 172.16.2.2 Serial0/2

Rosario#172.16.3.2 (nos conectamos)

Trying 172.16.3.2 ...Open

User Access Verification

Password: (cisco)

Telmex>sh ip ospf nei (buscamos vecinos)

Neighbor ID Pri State Dead Time Address Interface

172.16.3.1 0 FULL/ - 00:00:36 172.16.3.1 Serial0/0

172.16.7.1 0 FULL/ - 00:00:36 172.16.7.1 Serial0/1 (elegimos uno)

Telmex>172.16.7.1 (nos conectamos)

Trying 172.16.7.1 ...Open

User Access Verification

Password: (cisco)

Cordoba>enable

Password: (class)

Cordoba#sh ip ospf nei (verificamos vecinos)

Neighbor ID Pri State Dead Time Address Interface

172.16.7.2 0 FULL/ - 00:00:30 172.16.7.2 Serial0/3 (Telmex)

172.16.6.2 0 FULL/ - 00:00:32 172.16.6.2 Serial0/2

172.16.4.2 0 FULL/ - 00:00:32 172.16.4.2 Serial0/0

172.16.5.2 0 FULL/ - 00:00:30 172.16.5.2 Serial0/1

Cambios de configuración

Cordoba#conf t

Enter configuration commands, one per line. End with CNTL/Z.

Cordoba(config)#int s0/3

Cordoba(config-if)#encap ppp (cambiamos protocolo, la conexión se perderá)

% Connection refused by remote host

Telmex>

Telmex#sh int s0/1 (interfaz involucrada)

Serial0/1 is up, line protocol is down (disabled)

Hardware is HD64570

Internet address is 172.16.7.2/24

MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec,

reliability 255/255, txload 1/255, rxload 1/255

Encapsulation HDLC, loopback not set, keepalive set (10 sec)

Last input never, output never, output hang never

---resumido---

Telmex#conf t

Enter configuration commands, one per line. End with CNTL/Z.

Telmex(config)#int s0/1

Telmex(config-if)#encap ppp (cambiamos protocolo, la conexión se reestablece)

Telmex(config-if)#^Z

Telmex#sh int s0/1 (verificamos)

Serial0/1 is up, line protocol is up (connected)

Hardware is HD64570

Internet address is 172.16.7.2/24

MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec,

reliability 255/255, txload 1/255, rxload 1/255

Encapsulation PPP, loopback not set, keepalive set (10 sec)

LCP Open (subcapa inferior)

Open: IPCP, CDPCP (protocolos de capa 3 que utilizan el protocolo de capa 2)

Last input never, output never, output hang never

---resumido---

Telmex#conf t

Enter configuration commands, one per line. End with CNTL/Z.

Telmex(config)#int s0/0 (interfaz involucrada a Rosario)

Telmex(config-if)#encap ppp (cambiamos protocolo, la conexión se perderá)

% Connection refused by remote host

Rosario#

Rosario#sh int s0/3 (interfaz involucrada)

Serial0/3 is up, line protocol is down (disabled)

Hardware is HD64570

Internet address is 172.16.3.1/24

MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec,

reliability 255/255, txload 1/255, rxload 1/255

Encapsulation HDLC, loopback not set, keepalive set (10 sec)

Last input never, output never, output hang never

---resumido---

Rosario#

Rosario#conf t

Enter configuration commands, one per line. End with CNTL/Z.

Rosario(config)#int s0/3

Rosario(config-if)#encap ppp (cambiamos protocolo, la conexión se reestablece)

Rosario(config-if)#^Z

Rosario#

%SYS-5-CONFIG_I: Configured from console by console

%LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/3, changed state to up

00:10:30: %OSPF-5-ADJCHG: Process 1, Nbr 172.16.7.2 on Serial0/3 from LOADING to FULL, Loading Done

Rosario#sh int s0/3 (verificamos)

Serial0/3 is up, line protocol is up (connected)

Hardware is HD64570

Internet address is 172.16.3.1/24

MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec,

reliability 255/255, txload 1/255, rxload 1/255

Encapsulation PPP, loopback not set, keepalive set (10 sec)

LCP Open

Open: IPCP, CDPCP

Last input never, output never, output hang never

---resumido---

Rosario#

Rosario#sh ip route (verificamos)

---resumido---

10.0.0.0/24 is subnetted, 2 subnets

C 10.0.1.0 is directly connected, FastEthernet0/0

O 10.0.2.0 [110/129] via 172.16.2.2, 00:01:00, Serial0/2

[110/129] via 172.16.0.2, 00:01:00, Serial0/0

[110/129] via 172.16.1.2, 00:01:00, Serial0/1

[110/129] via 172.16.3.2, 00:01:00, Serial0/3

172.16.0.0/16 is variably subnetted, 9 subnets, 2 masks

C 172.16.0.0/24 is directly connected, Serial0/0

C 172.16.1.0/24 is directly connected, Serial0/1

C 172.16.2.0/24 is directly connected, Serial0/2

C 172.16.3.0/24 is directly connected, Serial0/3

C 172.16.3.2/32 is directly connected, Serial0/3

O 172.16.4.0/24 [110/128] via 172.16.0.2, 00:11:11, Serial0/0

O 172.16.5.0/24 [110/128] via 172.16.1.2, 00:11:11, Serial0/1

O 172.16.6.0/24 [110/128] via 172.16.2.2, 00:11:11, Serial0/2

O 172.16.7.0/24 [110/128] via 172.16.3.2, 00:01:00, Serial0/3 (segmento migrado)

Rosario#

Rosario#trace 172.16.7.1 (verificamos tráfico, la IP es la Serial0/3 de Córdoba)

Type escape sequence to abort.

Tracing the route to 172.16.7.1

1 172.16.3.2 31 msec 31 msec 32 msec (Rosario-Telmex)

2 172.16.7.1 50 msec 63 msec 63 msec (Telmex-Córdoba)

Rosario#

Migramos PPP con autenticación CHAP

Rosario#172.16.3.2

Trying 172.16.3.2 ...Open

User Access Verification

Password: (cisco)

Telmex>ena

Password: (class)

Telmex#172.16.7.1

Trying 172.16.7.1 ...Open

User Access Verification

Password: (cisco)

Cordoba>ena

Password: (class)

Cordoba#conf t

Enter configuration commands, one per line. End with CNTL/Z.

Cordoba(config)#username Telmex pass P4$$word (atención case-sensitive)

Cordoba(config)#int s0/3

Cordoba(config-if)#ppp authentication chap (la conexión se cortará)

% Connection timed out; remote host not responding

Telmex#

Telmex#conf t

Enter configuration commands, one per line. End with CNTL/Z.

Telmex(config)#username Cordoba password P4$$word (atención case-sensitive)

Telmex(config)#username Rosario password P4$$word (atención case-sensitive)

Telmex(config)#int s0/1

Telmex(config-if)#ppp auth chap (el otro extremo ya es CHAP)

Telmex(config-if)#exit

Telmex(config)#int s0/0

Telmex(config-if)#ppp auth chap (la conexión se cortará)

%LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/3, changed state to down

00:17:01: %OSPF-5-ADJCHG: Process 1, Nbr 172.16.7.2 on Serial0/3 from FULL to DOWN,

Neighbor Down: Interface down or detached

% Connection timed out; remote host not responding

Rosario#

Rosario#conf t

Enter configuration commands, one per line. End with CNTL/Z.

Rosario(config)#username Telmex pass P4$$word (atención case-sensitive)

Rosario(config)#int s0/3

Rosario(config-if)#ppp auth chap (el otro extremo ya es CHAP)

%LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/3, changed state to up

00:17:58: %OSPF-5-ADJCHG: Process 1, Nbr 172.16.7.2 on Serial0/3 from LOADING to FULL, Loading Done

Rosario(config-if)#^Z

Rosario#sh ip route (verificamos)

---resumido---

10.0.0.0/24 is subnetted, 2 subnets

C 10.0.1.0 is directly connected, FastEthernet0/0

O 10.0.2.0 [110/129] via 172.16.2.2, 00:01:01, Serial0/2 (Córdoba vía 3 enlaces de 4)

[110/129] via 172.16.0.2, 00:01:01, Serial0/0

[110/129] via 172.16.1.2, 00:01:01, Serial0/1

172.16.0.0/16 is variably subnetted, 9 subnets, 2 masks

C 172.16.0.0/24 is directly connected, Serial0/0

C 172.16.1.0/24 is directly connected, Serial0/1

C 172.16.2.0/24 is directly connected, Serial0/2

C 172.16.3.0/24 is directly connected, Serial0/3

C 172.16.3.2/32 is directly connected, Serial0/3

O 172.16.4.0/24 [110/128] via 172.16.0.2, 00:17:37, Serial0/0

O 172.16.5.0/24 [110/128] via 172.16.1.2, 00:17:37, Serial0/1

O 172.16.6.0/24 [110/128] via 172.16.2.2, 00:17:37, Serial0/2

O 172.16.7.0/24 [110/192] via 172.16.2.2, 00:01:01, Serial0/2 (todavía no hay convergencia, esta red

[110/192] via 172.16.0.2, 00:01:01, Serial0/0 se alcanza vía los otros 3 ISP, ver el

[110/192] via 172.16.1.2, 00:01:01, Serial0/1 costo cuando el enlace esté UP UP)

Rosario#sh ip route (nuevamente)

---resumido---

10.0.0.0/24 is subnetted, 2 subnets

C 10.0.1.0 is directly connected, FastEthernet0/0

O 10.0.2.0 [110/129] via 172.16.2.2, 00:00:12, Serial0/2 (Córdoba vía 4 enlaces de 4)

[110/129] via 172.16.0.2, 00:00:12, Serial0/0

[110/129] via 172.16.1.2, 00:00:12, Serial0/1

[110/129] via 172.16.3.2, 00:00:12, Serial0/3

172.16.0.0/16 is variably subnetted, 9 subnets, 2 masks

C 172.16.0.0/24 is directly connected, Serial0/0

C 172.16.1.0/24 is directly connected, Serial0/1

C 172.16.2.0/24 is directly connected, Serial0/2

C 172.16.3.0/24 is directly connected, Serial0/3

C 172.16.3.2/32 is directly connected, Serial0/3

O 172.16.4.0/24 [110/128] via 172.16.0.2, 00:17:50, Serial0/0

O 172.16.5.0/24 [110/128] via 172.16.1.2, 00:17:50, Serial0/1

O 172.16.6.0/24 [110/128] via 172.16.2.2, 00:17:50, Serial0/2

O 172.16.7.0/24 [110/128] via 172.16.3.2, 00:00:12, Serial0/3 (ver ahora el costo OSPF menor)

Rosario#trace 172.16.7.1 (verificamos)

Type escape sequence to abort.

Tracing the route to 172.16.7.1

1 172.16.3.2 31 msec 31 msec 31 msec (Telmex)

2 172.16.7.1 62 msec 47 msec 62 msec (Córdoba)

Rosario#

El escenario un día sin nubes:

Escenario alternativo:user y pass mal configurados

Rosario#debug ppp auth (monitoreo de la autenticación)

Rosario#debug ppp nego (monitoreo de negociación LCP)

Rosario#conf t

Enter configuration commands, one per line. End with CNTL/Z.

Rosario(config)#username Telmex pass Pa$$word (en router Telmex es P4$$word)

Rosario(config)#int s0/3

Rosario(config-if)#shut (bajamos el enlace)

%LINK-5-CHANGED: Interface Serial0/3, changed state to administratively down

Serial0/3 PPP: Phase is TERMINATING

Serial0/3 LCP: State is Closed

Serial0/3 PPP: Phase is DOWN

%LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/3, changed state to down

00:22:38: %OSPF-5-ADJCHG: Process 1, Nbr 172.16.7.2 on Serial0/3 from FULL to DOWN,

Neighbor Down: Interface down or detached

Rosario(config-if)#no shut (levantamos enlace)

%LINK-5-CHANGED: Interface Serial0/3, changed state to up

Serial0/3 PPP: Using default call direction

Serial0/3 PPP: Treating connection as a dedicated line

Serial0/3 PPP: Phase is ESTABLISHING, Active Open

Serial0/3 LCP: State is Open

Serial0/3 PPP: Phase is AUTHENTICATING

Serial0/3 IPCP: O CONFREQ [Closed] id 1 len 10

Serial0/3 IPCP: I CONFACK [Closed] id 1 len 10

Serial0/3 IPCP: O CONFREQ [Closed] id 1 len 10

Serial0/3 IPCP: I CONFNACK [REQsent] id 1 len 10

Serial0/3 IPCP: I CONFREQ [Closed] id 1 len 10 (nuevo intento)

Serial0/3 IPCP: O CONFACK [Closed] id 1 len 10

Serial0/3 IPCP: I CONFREQ [REQsent] id 1 len 10

Serial0/3 IPCP: O CONFNACK [REQsent] id 1 len 10

Rosario(config-if)#shut (bajamos el enlace)

%LINK-5-CHANGED: Interface Serial0/3, changed state to administratively down

Serial0/3 PPP: Phase is TERMINATING

Serial0/3 LCP: State is Closed

Serial0/3 PPP: Phase is DOWN

Rosario(config-if)#exit

Rosario(config)#username Telmex pass P4$$word (corregimos password)

Rosario(config)#int s0/3

Rosario(config-if)#no shut (levantamos nuevamente)

%LINK-5-CHANGED: Interface Serial0/3, changed state to up

Serial0/3 PPP: Using default call direction

Serial0/3 PPP: Treating connection as a dedicated line

Serial0/3 PPP: Phase is ESTABLISHING, Active Open

Serial0/3 LCP: State is Open

Serial0/3 PPP: Phase is AUTHENTICATING

Serial0/3 IPCP: O CONFREQ [Closed] id 1 len 10

Serial0/3 IPCP: I CONFACK [Closed] id 1 len 10

Serial0/3 IPCP: O CONFREQ [Closed] id 1 len 10

Serial0/3 IPCP: I CONFACK [REQsent] id 1 len 10

Serial0/3 PPP: Phase is FORWARDING, Attempting Forward

Serial0/3 Phase is ESTABLISHING, Finish LCP

Serial0/3 Phase is UP

%LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/3, changed state to up

00:22:03: %OSPF-5-ADJCHG: Process 1, Nbr 172.16.7.2 on Serial0/3 from LOADING to FULL, Loading Done

(2012) Networking is a scarecrow for pretty girls

Rosario, Argentina