MAC Flapping

[marcoanvm]

Buen Día, tengo el siguiente problema con la vlan 50, lo que ocasiona que toda esa vlan se quede sin red. 

Aug 27 08:44:45.004: %SW_MATM-4-MACFLAP_NOTIF: Host 80ce.62a4.9f96 in vlan 50 is flapping between port Gi2/0/47 and port Gi2/0/2
Aug 27 08:44:45.120: %SW_MATM-4-MACFLAP_NOTIF: Host 80ce.62a5.5559 in vlan 50 is flapping between port Gi2/0/47 and port Gi2/0/12
Aug 27 08:44:45.191: %SW_MATM-4-MACFLAP_NOTIF: Host 80ce.62a5.35d4 in vlan 50 is flapping between port Gi2/0/47 and port Gi2/0/15
Aug 27 08:44:45.193: %SW_MATM-4-MACFLAP_NOTIF: Host e86a.645a.bbbb in vlan 50 is flapping between port Gi2/0/47 and port Gi2/0/18
Aug 27 08:44:45.201: %SW_MATM-4-MACFLAP_NOTIF: Host 80ce.62a4.7f87 in vlan 50 is flapping between port Gi2/0/47 and port Gi2/0/29
Aug 27 08:44:45.385: %SW_MATM-4-MACFLAP_NOTIF: Host 10e7.c66e.0c7e in vlan 50 is flapping between port Gi2/0/47 and port Gi2/0/35
Aug 27 08:44:45.388: %SW_MATM-4-MACFLAP_NOTIF: Host 0026.7344.f063 in vlan 50 is flapping between port Gi2/0/47 and port Gi2/0/24
Aug 27 08:44:45.491: %SW_MATM-4-MACFLAP_NOTIF: Host 80ce.62a5.4528 in vlan 50 is flapping between port Gi2/0/47 and port Gi2/0/33

Los trunks estan configurados de la siguiente manera

interface GigabitEthernet2/0/47
description To SWLM-S21
switchport trunk allowed vlan 1,2,40,50,51,102-114,120-122,200
switchport mode trunk

[luis_cordova]

Hola @marcoanvm ,

El flapeo de MAC, en ocaciones, es debido a loops.

Tienes alguna redundancia en tu red?

Puedes verificar que STP esté bien configurado?

Saludos

[marcoanvm]

Si, es probable, para la redundacia no utilizo varios switches, tenemos port channel de cara a el Firewall.

El error me arroja en el equipo que da cara a el Firewall, para conectar el otro switch, tan solo hacemos una cascada y no requerimos de STP. 

[Julio E. Moisa]

Hola

Solo para estar claros con esto:  tan solo hacemos una cascada y no requerimos de STP. ¿Tienes deshabilitado el STP? Eso no es recomendable. 

Ahora bien como menciona @luis_cordova , ese flapping es un loop de capa 2, existen muchas razones:

- Conexion fisica que genera el loop

- Roaming de computadoras entre equipos Access Points

- Equipos finales que generan algun tipo de mensaje como BPDUs

etc.

Primero debes rastrear que hay ese puerto y si hay otro dispositivo verificar si ahi tambien se muestra el mensaje, en el mejor de los casos es contactar al Cisco TAC, hay ciertas lineas de comandos que pueden apoyar a identificar la causa.

Saludos 

[luis_cordova]

Hola @marcoanvm ,

Que dispositivos están conectados a las interfaces entre las que flapea las MACs?

Revistaste que las configuraciones del PortChannel en ambos extremos sea correcto?

Saludos

[marcoanvm]

Son teléfonos Yealink y Computadoras, si esta habilitado STP. 

Entre ambos Switches no se tiene Port Channel, 

Adjunto configuracion de ambos extremos

Current configuration : 146 bytes
!
interface GigabitEthernet1/0/48
description TO-B11
switchport trunk allowed vlan 1,2,40,50,51,102-114,120-122,200
switchport mode trunk
end

interface GigabitEthernet2/0/47
description To SWLM-S21
switchport trunk allowed vlan 1,2,40,50,51,102-114,120-122,200
switchport mode trunk
end

Puerto de Acceso

SWLM-B11#sh run int Gi2/0/9
Building configuration...

Current configuration : 138 bytes
!
interface GigabitEthernet2/0/9
switchport access vlan 50
switchport mode access
switchport voice vlan 2
spanning-tree portfast
end

SWLM-B11#

[luis_cordova]

Hola @marcoanvm ,

Creo que el problema puede estar en las configuraciones entre el switch y el firewall.

Revisa las configuraciones del PortChannel en ambos extremos.

Saludos

[marcoanvm]

Hola,

Corrí un debug y me arrojo lo siguiente:

Aug 27 14:04:02.030: %SW_MATM-4-MACFLAP_NOTIF: Host 001a.6494.7e4c in vlan 50 is flapping between port Gi2/0/47 and port Gi2/0/46
Aug 27 14:04:02.057: %SW_MATM-4-MACFLAP_NOTIF: Host 8c89.a53b.3bf5 in vlan 50 is flapping between port Gi2/0/47 and port Gi2/0/48
Aug 27 14:04:02.142: %SW_MATM-4-MACFLAP_NOTIF: Host 0009.0f09.000a in vlan 50 is flapping between port Gi2/0/47 and port Po2
Aug 27 14:04:04.108: %SW_MATM-4-MACFLAP_NOTIF: Host 805e.c053.0df1 in vlan 50 is flapping between port Gi2/0/47 and port Gi2/0/9
Aug 27 14:04:04.489: %SW_MATM-4-MACFLAP_NOTIF: Host 000c.29c0.1828 in vlan 50 is flapping between port Gi2/0/47 and port Gi2/0/46
Aug 27 14:04:04.593: %SW_MATM-4-MACFLAP_NOTIF: Host 0009.0f09.000a in vlan 2 is flapping between port Gi2/0/47 and port Po2
Aug 27 14:04:05.135: %SW_MATM-4-MACFLAP_NOTIF: Host 0023.24a3.1753 in vlan 50 is flapping between port Gi2/0/47 and port Gi2/0/48
Aug 27 14:04:06.209: %SW_MATM-4-MACFLAP_NOTIF: Host 10e7.c671.621b in vlan 50 is flapping between port Gi2/0/47 and port Gi1/0/39
Aug 27 14:04:06.371: RSTP(50): Gi2/0/47 rcvd info expired
Aug 27 14:04:06.372: RSTP(50): updt roles, information on root port Gi2/0/47 expired
Aug 27 14:04:06.372: RSTP(50): we become the root bridge
Aug 27 14:04:06.377: RSTP(50): Gi2/0/47 is now designated
Aug 27 14:04:06.378: RSTP(2): Gi2/0/47 rcvd info expired
Aug 27 14:04:06.379: RSTP(2): updt roles, information on root port Gi2/0/47 expired
Aug 27 14:04:06.379: RSTP(2): we become the root bridge
Aug 27 14:04:06.383: RSTP(2): Gi2/0/47 is now designated
Aug 27 14:04:06.402: RSTP(50): updt roles, received superior bpdu on Gi2/0/47
Aug 27 14:04:06.402: RSTP(50): Gi2/0/47 is now root port
Aug 27 14:04:06.403: RSTP(50): starting topology change timer for 35 seconds
Aug 27 14:04:06.403: STP[50]: Generating TC trap for port GigabitEthernet2/0/47
Aug 27 14:04:06.410: RSTP(2): updt roles, received superior bpdu on Gi2/0/47
Aug 27 14:04:06.410: RSTP(2): Gi2/0/47 is now root port
Aug 27 14:04:06.410: RSTP(2): starting topology change timer for 35 seconds
Aug 27 14:04:06.411: STP[2]: Generating TC trap for port GigabitEthernet2/0/47
Aug 27 14:04:07.382: RSTP(50): Gi2/0/47 received a tc ack
Aug 27 14:04:07.411: RSTP(2): Gi2/0/47 received a tc ack
Aug 27 14:04:13.384: RSTP(50): Gi2/0/47 rcvd info expired
Aug 27 14:04:13.385: RSTP(50): updt roles, information on root port Gi2/0/47 expired
Aug 27 14:04:13.385: RSTP(50): we become the root bridge
Aug 27 14:04:13.391: RSTP(50): Gi2/0/47 is now designated
Aug 27 14:04:13.411: RSTP(2): Gi2/0/47 rcvd info expired
Aug 27 14:04:13.411: RSTP(2): updt roles, information on root port Gi2/0/47 expired
Aug 27 14:04:13.412: RSTP(2): we become the root bridge
Aug 27 14:04:13.417: RSTP(2): Gi2/0/47 is now designated
Aug 27 14:04:13.427: RSTP(50): updt roles, received superior bpdu on Gi2/0/47
Aug 27 14:04:13.428: RSTP(50): Gi2/0/47 is now root port
Aug 27 14:04:13.428: RSTP(50): starting topology change timer for 35 seconds
Aug 27 14:04:13.428: STP[50]: Generating TC trap for port GigabitEthernet2/0/47
Aug 27 14:04:13.436: RSTP(2): updt roles, received superior bpdu on Gi2/0/47
Aug 27 14:04:13.436: RSTP(2): Gi2/0/47 is now root port
Aug 27 14:04:13.436: RSTP(2): starting topology change timer for 35 seconds
Aug 27 14:04:13.437: STP[2]: Generating TC trap for port GigabitEthernet2/0/47
Aug 27 14:04:14.395: RSTP(50): Gi2/0/47 received a tc ack
Aug 27 14:04:14.420: RSTP(2): Gi2/0/47 received a tc ack
Aug 27 14:04:20.394: RSTP(50): Gi2/0/47 rcvd info expired
Aug 27 14:04:20.395: RSTP(50): updt roles, information on root port Gi2/0/47 expired
Aug 27 14:04:20.395: RSTP(50): we become the root bridge
Aug 27 14:04:20.401: RSTP(50): Gi2/0/47 is now designated
Aug 27 14:04:20.411: RSTP(50): updt roles, received superior bpdu on Gi2/0/47
Aug 27 14:04:20.411: RSTP(50): Gi2/0/47 is now root port
Aug 27 14:04:20.411: RSTP(50): starting topology change timer for 35 seconds
Aug 27 14:04:20.412: STP[50]: Generating TC trap for port GigabitEthernet2/0/47
Aug 27 14:04:21.409: RSTP(50): Gi2/0/47 received a tc ack
Aug 27 14:04:48.437: RSTP(2): stopping topology change timer
Aug 27 14:04:48.514: RSTP(2): starting topology change timer for 35 seconds
Aug 27 14:04:55.412: RSTP(50): stopping topology change timer
Aug 27 14:04:56.506: RSTP(50): starting topology change timer for 35 seconds
Aug 27 14:05:23.517: RSTP(2): stopping topology change timer
Aug 27 14:05:24.601: RSTP(2): starting topology change timer for 35 seconds
Aug 27 14:05:31.506: RSTP(50): stopping topology change timer

[luis_cordova]

Hola @marcoanvm ,

Que dispositivo está conectado a Gi2/0/47?

Con el log que muestras, se evidencia que el problema está relacionado con STP.

Saludos

[marcoanvm]

A el puerto Gi2/0/47 se encuentra conectado el Firewall, por lo que veo se tienen varios cambios de topologias para la VLAN 50 y VLAN 2, lo raro que para el resto de VLAN no se tiene problemas.

[luis_cordova]

Hola @marcoanvm ,

Recuerdo que indicaste que entre el switch y el firewall había un PortChannel.

En las configuraciones que enviaste de este puerto no veo que esté asociado a un PortChannel.

Podrias compartir las configuraciones de los puertos del switch que conectan con el firewall y las configuraciones de las interfaces del firewall que conectan con el switch?

Apostaría a que el problema se encuentra en esas configuraciones :)

Saludos

[marcoanvm]

Perdon, el puerto Gi2/0/47 es el trunk que da cara con el otro switch.

SWLM-B11#sh run int GigabitEthernet2/0/47
Building configuration...

Current configuration : 152 bytes
!
interface GigabitEthernet2/0/47
description To SWLM-S21
switchport trunk allowed vlan 1,2,40,50,51,102-114,120-122,200
switchport mode trunk
end

SWLM-B11#

Configuracion de el PortChannel

SWLM-B11# sh run int Gi2/0/44
Building configuration...

Current configuration : 146 bytes
!
interface GigabitEthernet2/0/44
description Port-Channel Opt
switchport mode trunk
speed 1000
duplex full
channel-group 2 mode active
end

SWLM-B11#

SWLM-B11#sh run int po2
Building configuration...

Current configuration : 54 bytes
!
interface Port-channel2
switchport mode trunk
end

SWLM-B11#

[Alfredo Elias]

Por los log mostrados efectivamente tienes un loop de capa 2 en los switches aunque solo sean dos lo que yo te recomiendo es lo siguiente:

Que coloques un root de vlan en uno de los switches esto te ayudara a que los cambios de topologias generados por loop se han de menos impacto en la red la prioridad debe ser 0 te envio un ejemplo.

spanning-tree vlan 1-8,10,29,200,210,240-247,350,400,551,662,2173 priority 0

Saludos,