Por Ernesto Vilarrasa -- Rosario - Argentina
Tomado de: http://www.vilarrasa.com.ar/rip_con_25_redes.htm
Prueba de cantidad máxima de redes publicadas en RIP
Tomado de: http://www.vilarrasa.com.ar/rip_con_25_redes.htm
Prueba de cantidad máxima de redes publicadas en RIP
Fecha: 4 de Octubre del 2012 Clase: Exploration 2
Detalle
Repasando el tema para la clase del 4 de Octubre, me
quedo con un gráfico de la currícula donde está el scope de un
paquete RIP y detalla un máximo de 25 redes
publicadas, esto no sebe confundirse con la cantidad máxima de saltos,
que es 15. ¿ Entonces, que pasaría si hay mas de 25
redes ? allí vamos, pasemos los límites.
Puntos 7.1.3
y 7.2.1 de Exploration 2
Buscamos en la RFC de RIP v2
3. Protocol Extensions
This document does not change the RIP protocol per se. Rather, it
provides extensions to the message format which allows routers
to
share important additional information.
The first four octets of a RIP message contain the RIP
header. The
remainder of the message is composed of 1 - 25 route entries
(20
octets each). The new
RIP message format is:
0
1 2 3 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Command (1) | Version
(1) | unused
|
+---------------+---------------+-------------------------------+
| Address Family Identifier (2) | Route Tag (2)
|
+-------------------------------+-------------------------------+
|
IP Address (4)
|
+---------------------------------------------------------------+
| Subnet Mask (4) |
+---------------------------------------------------------------+
|
Next Hop (4)
|
+---------------------------------------------------------------+
|
Metric (4)
|
+---------------------------------------------------------------+
Escenario
Configuramos en Packet Tracer un router 1841 con 29
interfaces loopback para simular las 29 redes, y realizamos el debug
de RIP para ver tanto las actualizaciones salientes,
como las entrantes en router Borde, que tiene dos segmentos: 10.x.x.x
y 192.168.x.x , compartiendo la 10.0.0.0 /24, y por
lo tanto, no hay sumarización.
Borde#sh ip route (verificamos convergencia)
---resumido---
10.0.0.0/24 is subnetted, 26 subnets
C 10.0.0.0 is directly connected,
FastEthernet0/0
R 10.0.1.0 [120/1] via 10.0.0.1,
00:00:20, FastEthernet0/0 (1ra red)
R 10.0.2.0 [120/1] via 10.0.0.1,
00:00:20, FastEthernet0/0
R 10.0.3.0 [120/1] via 10.0.0.1,
00:00:20, FastEthernet0/0
R 10.0.4.0 [120/1] via 10.0.0.1,
00:00:20, FastEthernet0/0
R 10.0.5.0 [120/1] via 10.0.0.1,
00:00:20, FastEthernet0/0
R 10.0.6.0 [120/1] via 10.0.0.1,
00:00:20, FastEthernet0/0
R 10.0.7.0 [120/1] via 10.0.0.1,
00:00:20, FastEthernet0/0
R 10.0.8.0 [120/1] via 10.0.0.1,
00:00:20, FastEthernet0/0
R 10.0.9.0 [120/1] via 10.0.0.1,
00:00:20, FastEthernet0/0
R 10.0.10.0 [120/1] via 10.0.0.1,
00:00:20, FastEthernet0/0
R 10.0.11.0 [120/1] via 10.0.0.1,
00:00:20, FastEthernet0/0
R 10.0.12.0 [120/1] via 10.0.0.1,
00:00:20, FastEthernet0/0
R 10.0.13.0 [120/1] via 10.0.0.1,
00:00:20, FastEthernet0/0
R 10.0.14.0 [120/1] via 10.0.0.1,
00:00:20, FastEthernet0/0
R 10.0.15.0 [120/1] via 10.0.0.1,
00:00:19, FastEthernet0/0
R 10.0.16.0 [120/1] via 10.0.0.1,
00:00:19, FastEthernet0/0
R 10.0.17.0 [120/1] via 10.0.0.1,
00:00:19, FastEthernet0/0
R 10.0.18.0 [120/1] via 10.0.0.1,
00:00:19, FastEthernet0/0
R 10.0.19.0 [120/1] via 10.0.0.1,
00:00:19, FastEthernet0/0
R 10.0.20.0 [120/1] via 10.0.0.1,
00:00:19, FastEthernet0/0
R 10.0.21.0 [120/1] via 10.0.0.1,
00:00:19, FastEthernet0/0
R 10.0.22.0 [120/1] via 10.0.0.1,
00:00:19, FastEthernet0/0
R 10.0.23.0 [120/1] via 10.0.0.1,
00:00:19, FastEthernet0/0
R 10.0.24.0 [120/1] via 10.0.0.1,
00:00:19, FastEthernet0/0
R 10.0.25.0 [120/1] via 10.0.0.1,
00:00:19, FastEthernet0/0 (25ta red)
R 10.0.26.0 [120/1] via 10.0.0.1,
00:00:19, FastEthernet0/0
R 10.0.27.0 [120/1] via 10.0.0.1,
00:00:19, FastEthernet0/0
R 10.0.28.0 [120/1] via 10.0.0.1,
00:00:19, FastEthernet0/0
R 10.0.29.0 [120/1] via 10.0.0.1,
00:00:19, FastEthernet0/0
C 192.168.0.0/24 is directly connected,
FastEthernet0/1
Borde#deb ip rip
RIP protocol debugging is
on
Borde#
RIP: sending v1 update to 255.255.255.255 via
FastEthernet0/0 (10.0.0.2)
RIP: build update entries
network 192.168.0.0 metric 1
RIP: received v1 update
from 10.0.0.1 on FastEthernet0/0
10.0.1.0 in 1 hops
10.0.2.0 in 1 hops
10.0.3.0 in 1 hops
10.0.4.0 in 1 hops
10.0.5.0 in 1 hops
10.0.6.0 in 1 hops
10.0.7.0 in 1 hops
10.0.8.0 in 1 hops
10.0.9.0 in 1 hops
10.0.10.0 in 1 hops
10.0.11.0 in 1 hops
10.0.12.0 in 1 hops
10.0.13.0 in 1 hops
10.0.14.0 in 1 hops
10.0.15.0 in 1 hops
10.0.15.0 in 1 hops
10.0.16.0 in 1 hops
10.0.17.0 in 1 hops
10.0.18.0 in 1 hops
10.0.19.0 in 1 hops
10.0.20.0 in 1 hops
10.0.21.0 in 1 hops
10.0.22.0 in 1 hops
10.0.23.0 in 1 hops
10.0.24.0 in 1 hops
10.0.25.0 in 1 hops
RIP: received v1 update
from 10.0.0.1 on FastEthernet0/0 (actualización
extra,
10.0.26.0 in 1 hops instantánea, no es a los próximos
30 segundos)
10.0.27.0 in 1 hops
10.0.28.0 in 1 hops
10.0.29.0 in 1 hops
Borde#undebug all
All possible debugging has
been turned off
Borde#
Router_1#debug ip rip
RIP protocol debugging is
on
Router_1#
RIP: received v1 update
from 10.0.0.2 on FastEthernet0/0 (desde Borde)
192.168.0.0 in 1 hops
RIP: sending v1 update to 255.255.255.255 via Loopback29
(10.0.29.1)
RIP: build update entries
network 10.0.0.0 metric 1
network 10.0.1.0 metric 1
network 10.0.2.0 metric 1
network 10.0.3.0 metric 1
network 10.0.4.0 metric 1
network 10.0.5.0 metric 1
network 10.0.6.0 metric 1
network 10.0.7.0 metric 1
network 10.0.8.0 metric 1
network 10.0.9.0 metric 1
network 10.0.10.0 metric 1
network 10.0.11.0 metric 1
network 10.0.12.0 metric 1
network 10.0.13.0 metric 1
network 10.0.14.0 metric 1
network 10.0.15.0 metric 1
network 10.0.16.0 metric 1
network 10.0.17.0 metric 1
network 10.0.18.0 metric 1
network 10.0.19.0 metric 1
network 10.0.20.0 metric 1
network 10.0.21.0 metric 1
network 10.0.22.0 metric 1
network 10.0.23.0 metric 1
network 10.0.24.0 metric 1
RIP: sending v1 update to 255.255.255.255 via Loopback29
(10.0.29.1)
RIP: build update entries (actualización extra)
network 10.0.25.0 metric 1
network 10.0.26.0 metric 1
network 10.0.27.0 metric 1
network 10.0.28.0 metric 1
network 192.168.0.0 metric 2
Router_1#undebug all
All possible debugging has
been turned off
Router_1#
Borde#sh runn
Building configuration...
Current configuration :
524 bytes
!
!
hostname Borde
!
interface FastEthernet0/0
ip address 10.0.0.2 255.255.255.0
!
interface FastEthernet0/1
ip address 192.168.0.1 255.255.255.0
!
router rip
network 10.0.0.0
network 192.168.0.0
!
end
Borde#
Router_1#sh runn
Building configuration...
Current configuration :
1312 bytes
!
!
hostname Router_1
!
interface Loopback1
ip address 10.0.1.1 255.255.255.0
!
interface Loopback2
ip address 10.0.2.1 255.255.255.0
!
interface Loopback3
ip address 10.0.3.1 255.255.255.0
!
interface Loopback4
ip address 10.0.4.1 255.255.255.0
!
interface Loopback5
ip address 10.0.5.1 255.255.255.0
!
interface Loopback6
ip address 10.0.6.1 255.255.255.0
!
interface Loopback7
ip address 10.0.7.1 255.255.255.0
!
interface Loopback8
ip address 10.0.8.1 255.255.255.0
!
interface Loopback9
ip address 10.0.9.1 255.255.255.0
!
interface Loopback10
ip address 10.0.10.1 255.255.255.0
!
interface Loopback11
ip address 10.0.11.1 255.255.255.0
!
interface Loopback12
ip address 10.0.12.1 255.255.255.0
!
interface Loopback13
ip address 10.0.13.1 255.255.255.0
!
interface Loopback14
ip address 10.0.14.1 255.255.255.0
!
interface Loopback15
ip address 10.0.15.1 255.255.255.0
!
interface Loopback16
ip address 10.0.16.1 255.255.255.0
!
interface Loopback17
ip address 10.0.17.1 255.255.255.0
!
interface Loopback18
ip address 10.0.18.1 255.255.255.0
!
interface Loopback19
ip address 10.0.19.1 255.255.255.0
!
interface Loopback20
ip address 10.0.20.1 255.255.255.0
!
interface Loopback21
ip address 10.0.21.1 255.255.255.0
!
interface Loopback22
ip address 10.0.22.1 255.255.255.0
!
interface Loopback23
ip address 10.0.23.1 255.255.255.0
!
interface Loopback24
ip address 10.0.24.1 255.255.255.0
!
interface Loopback25
ip address 10.0.25.1 255.255.255.0
!
interface Loopback26
ip address 10.0.26.1 255.255.255.0
!
interface Loopback27
ip address 10.0.27.1 255.255.255.0
!
interface Loopback28
ip address 10.0.28.1 255.255.255.0
!
interface Loopback29
ip address 10.0.29.1 255.255.255.0
!
interface FastEthernet0/0
ip address 10.0.0.1 255.255.255.0
!
router rip
network 10.0.0.0
!
ip classless
!
end
Router_1#
Prueba con equipo real, para sacarnos dudas de la
reacción de Packet Tracer.
Router# debug ip rip
*Oct 4 19:12:53.731: RIP: sending v1 update to
255.255.255.255 via FastEthernet0/0 (10.0.0.1)
*Oct 4 19:12:53.731: RIP: build update entries
*Oct 4 19:12:53.731: subnet 10.0.1.0 metric 1
*Oct 4 19:12:53.731: subnet 10.0.2.0 metric 1
*Oct 4 19:12:53.731: subnet 10.0.3.0 metric 1
*Oct 4 19:12:53.731: subnet 10.0.4.0 metric 1
*Oct 4 19:12:53.731: subnet 10.0.5.0 metric 1
*Oct 4 19:12:53.731: subnet 10.0.6.0 metric 1
*Oct 4 19:12:53.731: subnet 10.0.7.0 metric 1
*Oct 4 19:12:53.731: subnet 10.0.8.0 metric 1
*Oct 4 19:12:53.731: subnet 10.0.9.0 metric 1
*Oct 4 19:12:53.731: subnet 10.0.10.0 metric 1
*Oct 4 19:12:53.731: subnet 10.0.11.0 metric 1
*Oct 4 19:12:53.731: subnet 10.0.12.0 metric 1
*Oct 4 19:12:53.731: subnet 10.0.13.0 metric 1
*Oct 4 19:12:53.731: subnet 10.0.14.0 metric 1
*Oct 4 19:12:53.731: subnet 10.0.15.0 metric 1
*Oct 4 19:12:53.731: subnet 10.0.16.0 metric 1
*Oct 4 19:12:53.731: subnet 10.0.17.0 metric 1
*Oct 4 19:12:53.731: subnet 10.0.18.0 metric 1
*Oct 4 19:12:53.731: subnet 10.0.19.0 metric 1
*Oct 4 19:12:53.731: subnet 10.0.20.0 metric 1
*Oct 4 19:12:53.731: subnet 10.0.21.0 metric 1
*Oct 4 19:12:53.731: subnet 10.0.22.0 metric 1
*Oct 4 19:12:53.731: subnet 10.0.23.0 metric 1
*Oct 4 19:12:53.731: subnet 10.0.24.0 metric 1
*Oct 4 19:12:53.731: subnet 10.0.25.0 metric 1
*Oct 4 19:12:53.731: RIP: build update entries (actualización
extra)
*Oct 4 19:12:53.731: subnet 10.0.26.0 metric 1
*Oct 4 19:12:53.731: subnet 10.0.27.0 metric 1
*Oct 4 19:12:53.735: subnet 10.0.28.0 metric 1
*Oct 4 19:12:53.735: subnet 10.0.29.0 metric 1
Detalle de las tramas RIP
Frame 1 (546 bytes on
wire, 546 bytes captured)
Arrival Time: Oct 4, 2012 21:16:04.657240000 (primeras 25
redes)
[Time delta from previous captured frame: 0.000000000 seconds]
Frame 2 (126 bytes on
wire, 126 bytes captured)
Arrival Time: Oct 4, 2012 21:16:04.657310000 (no es
otra publicación a los 30 segundos)
[Time delta from previous captured frame: 0.000070000
seconds]
No. Time Source
Destination Protocol
Info
1 0.000000
10.0.0.1
255.255.255.255 RIPv1 Response
Ethernet II, Src: 00:1d:46:a5:27:60
(00:1d:46:a5:27:60), Dst: ff:ff:ff:ff:ff:ff (ff:ff:ff:ff:ff:ff)
Internet Protocol, Src: 10.0.0.1
(10.0.0.1), Dst: 255.255.255.255 (255.255.255.255)
User Datagram Protocol,
Src Port: 520 (520), Dst Port: 520 (520)
Routing Information
Protocol
Command: Response (2)
Version: RIPv1 (1)
IP Address: 10.0.1.0, Metric: 1
IP Address: 10.0.2.0, Metric: 1
IP Address: 10.0.3.0, Metric: 1
IP Address: 10.0.4.0, Metric: 1
IP Address: 10.0.5.0, Metric: 1
IP Address: 10.0.6.0, Metric: 1
IP Address: 10.0.7.0, Metric: 1
IP Address: 10.0.8.0, Metric: 1
IP Address: 10.0.9.0, Metric: 1
IP Address: 10.0.10.0, Metric: 1
IP Address: 10.0.11.0, Metric: 1
IP Address: 10.0.12.0, Metric: 1
IP Address: 10.0.13.0, Metric: 1
IP Address: 10.0.14.0, Metric: 1
IP Address: 10.0.15.0, Metric: 1
IP Address: 10.0.16.0, Metric: 1
IP Address: 10.0.17.0, Metric: 1
IP Address: 10.0.18.0, Metric: 1
IP Address: 10.0.19.0, Metric: 1
IP Address: 10.0.20.0, Metric: 1
IP Address: 10.0.21.0, Metric: 1
IP Address: 10.0.22.0, Metric: 1
IP Address: 10.0.23.0, Metric: 1
IP Address: 10.0.24.0, Metric: 1
IP Address: 10.0.25.0, Metric: 1
No. Time Source
Destination Protocol
Info
2 0.000070 10.0.0.1 255.255.255.255 RIPv1 Response
Ethernet II, Src: 00:1d:46:a5:27:60
(00:1d:46:a5:27:60), Dst: ff:ff:ff:ff:ff:ff (ff:ff:ff:ff:ff:ff)
Internet Protocol, Src: 10.0.0.1
(10.0.0.1), Dst: 255.255.255.255 (255.255.255.255)
User Datagram Protocol,
Src Port: 520 (520), Dst Port: 520 (520)
Routing Information
Protocol
Command: Response (2)
Version: RIPv1 (1)
IP Address: 10.0.26.0, Metric: 1
IP Address: 10.0.27.0, Metric: 1
IP Address: 10.0.28.0, Metric: 1
IP Address: 10.0.29.0, Metric: 1
Datos del layer 4 de las capturas, según el RFC 1700
utime 519/udp unixtime
efs 520/tcp extended file name server
router 520/udp local routing process (on site);
# uses variant of
Xerox NS routing
# information protocol
# 521-524 Unassigned
timed 525/tcp timeserver
Reflexión: entonces, sirve de algo este escenario ? sólo se
trata de llevar al límite el protocolo y ver que pasa.
No existen routers reales con 29 interfaces loopback, pero sí un escenario
como el siguiente podría ser real,
aunque ningún administrador con amor propio
implementaría RIP.
Con OSPF u otro protocolo de enrutamiento esto no
sucedería ya que se intercambian bases de datos con información
acerca de las redes conocidas.
Asuncion#show ip route
---resumido---
Gateway of last resort is
172.16.4.2 to network 0.0.0.0
172.16.0.0/24 is
subnetted, 32 subnets
R 172.16.1.0 [120/1] via 172.16.2.1,
00:00:26, Serial0/1 (ruta aprendida por otra
interfaz)
C 172.16.2.0 is directly connected,
Serial0/1
C 172.16.3.0 is directly connected,
FastEthernet0/0
C 172.16.4.0 is directly connected,
Serial0/0
R 172.16.5.0 [120/1] via 172.16.4.2,
00:00:01, Serial0/0
R 172.16.6.0 [120/1] via 172.16.4.2,
00:00:01, Serial0/0
R 172.16.7.0 [120/2] via 172.16.4.2,
00:00:01, Serial0/0
R 172.16.8.0 [120/2] via 172.16.4.2,
00:00:01, Serial0/0
R 172.16.9.0 [120/3] via 172.16.4.2,
00:00:01, Serial0/0
R 172.16.10.0 [120/3] via 172.16.4.2,
00:00:01, Serial0/0
R 172.16.11.0 [120/4] via 172.16.4.2,
00:00:01, Serial0/0
R 172.16.12.0 [120/4] via 172.16.4.2,
00:00:01, Serial0/0
R 172.16.13.0 [120/5] via 172.16.4.2,
00:00:01, Serial0/0
R 172.16.14.0 [120/5] via 172.16.4.2,
00:00:01, Serial0/0
R 172.16.15.0 [120/6] via 172.16.4.2,
00:00:01, Serial0/0
R 172.16.16.0 [120/6] via 172.16.4.2,
00:00:01, Serial0/0
R 172.16.17.0 [120/7] via 172.16.4.2,
00:00:01, Serial0/0
R 172.16.18.0 [120/7] via 172.16.4.2,
00:00:01, Serial0/0
R 172.16.19.0 [120/8] via 172.16.4.2,
00:00:01, Serial0/0
R 172.16.20.0 [120/8] via 172.16.4.2,
00:00:01, Serial0/0
R 172.16.21.0 [120/9] via 172.16.4.2,
00:00:01, Serial0/0
R 172.16.22.0 [120/9] via 172.16.4.2,
00:00:01, Serial0/0
R 172.16.23.0 [120/10] via 172.16.4.2,
00:00:01, Serial0/0
R 172.16.24.0 [120/10] via 172.16.4.2,
00:00:01, Serial0/0
R 172.16.25.0 [120/11] via 172.16.4.2,
00:00:01, Serial0/0
R 172.16.26.0 [120/11] via 172.16.4.2,
00:00:01, Serial0/0
R 172.16.27.0 [120/12] via 172.16.4.2,
00:00:01, Serial0/0
R 172.16.28.0 [120/12] via 172.16.4.2,
00:00:01, Serial0/0
R 172.16.30.0 [120/13] via 172.16.4.2,
00:00:01, Serial0/0
R 172.16.31.0 [120/14] via 172.16.4.2,
00:00:01, Serial0/0
R 172.16.32.0 [120/14] via 172.16.4.2,
00:00:01, Serial0/0
R 172.16.33.0 [120/15] via 172.16.4.2,
00:00:01, Serial0/0
R* 0.0.0.0/0 [120/13] via 172.16.4.2,
00:00:01, Serial0/0 (29 rutas aprendidas en RIP vía
s0/0)
Asuncion#debug ip rip
RIP: received v1 update
from 172.16.4.2 on Serial0/0
0.0.0.0 in 13 hops
172.16.5.0 in 1 hops
172.16.6.0 in 1 hops
172.16.7.0 in 2 hops
172.16.8.0 in 2 hops
172.16.9.0 in 3 hops
172.16.10.0 in 3 hops
172.16.11.0 in 4 hops
172.16.12.0 in 4 hops
172.16.13.0 in 5 hops
172.16.14.0 in 5 hops
172.16.15.0 in 6 hops
172.16.16.0 in 6 hops
172.16.17.0 in 7 hops
172.16.18.0 in 7 hops
172.16.19.0 in 8 hops
172.16.20.0 in 8 hops
172.16.21.0 in 9 hops
172.16.22.0 in 9 hops
172.16.23.0 in 10 hops
172.16.24.0 in 10 hops
172.16.25.0 in 11 hops
172.16.26.0 in 11 hops
172.16.27.0 in 12 hops
172.16.28.0 in 12 hops
RIP: received v1 update
from 172.16.4.2 on Serial0/0
172.16.30.0 in 13 hops
172.16.31.0 in 14 hops
172.16.32.0 in 14 hops
172.16.33.0 in 15 hops
(2012) Networking scare pretty girls
Rosario, Argentina
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