Escenario
homenaje Alemania – Brasil
Fecha: 8 de julio del
2014
Escenario
Este escenario reproduce en forma simbólica el
toqueteo de Alemania contra Brasil, en el que terminó 7 a 1.
El fútbol no me interesa pero durante la clase miramos
el partido y me inspiró para llevarlo como un juego al ámbito del enrutamiento.
Objetivo: La jugada (el tracert) arranca desde el arco de Neuer, Lahm, Khedira,
Kross, Schweinsteiger, Müller, klose entra al área 0 y al arco.
El término “entra al área 0” implica utilizar OSPF, como este busca la
ruta mas corta (o la más rápida) no es posible el “toqueteo” de Alemania,
por lo tanto habrá que jugar con los anchos de
banda o los costos OSPF.
Solución
Una vez configurados todos los routers, primero
hay que verificar que el tracert “llegue al arco” por la vía mas corta (SPF).
PC>tracert
192.168.2.1
Tracing route to 192.168.2.1 over a
maximum of 30 hops:
1 0 ms 0 ms 0 ms 192.168.1.254 (Lahm)
2 0 ms 0 ms 0 ms 10.0.0.2 (Boateng)
3 0 ms 1 ms 0 ms 10.0.0.10 (Khedira)
4 0 ms 0 ms 0 ms 10.0.0.18
(Schweinsteiger)
5 0 ms 0 ms 0 ms 10.0.0.62 (Klose)
6 0 ms 0 ms 0 ms 192.168.2.1 (Julio César)
Trace complete.
PC>
Una vez completados
los bandwidth o ip ospf cost verificamos:
PC>tracert
192.168.2.1
Tracing route to 192.168.2.1 over a
maximum of 30 hops:
1 1 ms 0 ms 0 ms 192.168.1.254 (Lahm)
2 0 ms 0 ms 0 ms 10.0.0.26 (Kedira)
3 0 ms 0 ms 0 ms 10.0.0.38 (Kross)
4 0 ms 0 ms 0 ms 10.0.0.42
(Schweinsteiger)
5 0 ms 0 ms 0 ms 10.0.0.50 (Müller)
6 0 ms 0 ms 0 ms 10.0.0.54 (Klose)
7 0 ms 0 ms 0 ms 192.168.2.1 (Julio César)
Trace complete.
PC>
Cabe detallar lo siguiente: al seleccionar el camino del tracert (o de la pelota),
debemos jugar con el
bandwidth o el costo OSPF, pero, en Packet Tracert es una cosa o la otra y BW le
gana al costo OSPF:
Lahm#sh runn
Building configuration...
Current configuration : 827 bytes
!
version 12.2
---resumido---
!
hostname Lahm
!
!
interface FastEthernet0/0
ip
address 192.168.1.254 255.255.255.0
duplex
auto
speed auto
!
interface GigabitEthernet1/0
bandwidth
8000 (costo
OSPF: 12)
ip address
10.0.0.5 255.255.255.252
!
interface GigabitEthernet2/0
bandwidth
8000 (costo
OSPF: 12)
ip address
10.0.0.1 255.255.255.252
!
interface GigabitEthernet3/0 (bandwidth por
defecto, o sea 1 Gbps, o sea costo OSPF: 1)
ip address 10.0.0.25 255.255.255.252
!
---resumido---
!
end
Lahm#sh ip ospf int Gi3/0 (verificamos)
GigabitEthernet3/0 is up, line protocol is up
Internet address is
10.0.0.25/30, Area 0
Process ID 1, Router ID
192.168.1.254, Network Type BROADCAST, Cost:
1
Transmit Delay is 1 sec, State
DR, Priority 1
Designated Router (ID)
192.168.1.254, Interface address 10.0.0.25
Backup Designated Router (ID)
10.0.0.58, Interface address 10.0.0.26
Timer intervals configured,
Hello 10, Dead 40, Wait 40, Retransmit 5
Hello due in 00:00:03
Index 4/4, flood queue length 0
Next 0x0(0)/0x0(0)
Last flood scan length is 1,
maximum is 1
Last flood scan time is 0 msec,
maximum is 0 msec
Neighbor Count is 1, Adjacent
neighbor count is 1
Adjacent with neighbor
10.0.0.58 (Backup Designated Router)
Suppress hello for 0 neighbor(s)
Lahm#
Si configuramos el ancho de banda real:
Lahm(config)#interface GigabitEthernet3/0
Lahm(config-if)#band 2000
Lahm#sh int Gi3/0 (verificamos)
GigabitEthernet3/0 is up, line protocol is up (connected)
Hardware is Lance, address is
00d0.d3e7.0cab (bia 00d0.d3e7.0cab)
Internet address is 10.0.0.25/30
MTU 1500 bytes, BW 2000 Kbit, DLY 10 usec,
reliability 255/255, txload
1/255, rxload 1/255
Encapsulation ARPA, loopback not
set
---resumido---
Lahm#sh ip ospf int Gi3/0 (verificamos que cambia el costo)
GigabitEthernet3/0 is up, line protocol is up
Internet address is
10.0.0.25/30, Area 0
Process ID 1, Router ID
192.168.1.254, Network Type BROADCAST, Cost:
50
Transmit Delay is 1 sec, State
DR, Priority 1
---resumido---
Lahm#
Modificamos el costo:
Lahm(config-if)#ip ospf cost 1
(para que le gane al costo 12 de las
otras interfaces)
Lahm(config-if)#
Lahm#sh ip ospf int Gi3/0 (verificamos)
GigabitEthernet3/0 is up, line protocol is up
Internet address is
10.0.0.25/30, Area 0
Process ID 1, Router ID
192.168.1.254, Network Type BROADCAST, Cost:
50 (no cambia)
Transmit Delay is 1 sec, State
DR, Priority 1
---resumido---
Lahm#
Prueba en un equipo real:
C1841#sh ip ospf int fa0/0 (verificamos costo 1)
FastEthernet0/0
is up, line protocol is up
Internet Address 192.168.0.1/24, Area 0
Process ID 1, Router ID 192.168.72.253, Network Type BROADCAST, Cost: 1
Transmit Delay is 1 sec, State WAITING, Priority 1
---resumido---
C1841#conf t
(modificamos BW, del costo cambiaría a 10^8/2.000.000=50)
Enter
configuration commands, one per line. End with
CNTL/Z.
C1841(config)#int
fa0/0
C1841(config-if)#band 2000
C1841(config-if)#^Z
C1841#sh ip ospf int fa0/0 (verificamos costo)
FastEthernet0/0
is up, line protocol is up
Internet Address 192.168.0.1/24, Area 0
Process ID 1, Router ID 192.168.72.253, Network Type BROADCAST, Cost: 50 (OK)
Transmit Delay is 1 sec, State DR, Priority 1
---resumido---
C1841#conf t
Enter
configuration commands, one per line. End with
CNTL/Z.
C1841(config)#int
fa0/0 (modificamos costo sin alterar el BW)
C1841(config-if)#ip ospf cost 1
C1841(config-if)#^Z
C1841#sh ip ospf int fa0/0
FastEthernet0/0
is up, line protocol is up
Internet Address 192.168.0.1/24, Area 0
Process ID 1, Router ID 192.168.72.253, Network Type BROADCAST, Cost: 1
Transmit
Delay is 1 sec, State DR, Priority 1
---resumido---
C1841#sh int fa0/0
(verificamos BW alterado por el costo)
FastEthernet0/0
is up, line protocol is up
Hardware is Gt96k FE, address is 001f.9ec9.0b16 (bia 001f.9ec9.0b16)
Internet address is 192.168.0.1/24
MTU 1500 bytes, BW 2000 Kbit/sec,
DLY 100 usec,
(no cambia, sólo sucede en Packet Tracer)
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full-duplex,
100Mb/s, 100BaseTX/FX
---resumido---
C1841#
C1841#sh runn
Building configuration...
Current configuration : 827 bytes
!
version 12.4
---resumido---
!
hostname C1841
!
interface FastEthernet0/0
ip
address 192.168.1.254 255.255.255.0
duplex
auto
speed auto
!
interface GigabitEthernet1/0
bandwidth
8000 (costo
OSPF: 12)
ip address
10.0.0.5 255.255.255.252
!
interface GigabitEthernet2/0
bandwidth
8000 (costo
OSPF: 12)
ip address
10.0.0.1 255.255.255.252
!
interface GigabitEthernet3/0
bandwidth 2000
ip
address 10.0.0.25 255.255.255.252
ip ospf cost 1
!
---resumido---
!
end
De la currícula Exploration 2:
(2014) Talking about networking scares pretty
girls
Rosario, Argentina