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We are facing some problem with configuration of servers: There are 2 servers, each one contain 2 NICs which are in bond. Each server is connected to 2 Cisco switches (one connection from each NIC to separate switch). The port on the switch is configured to have VLAN 1111. There is also interconnection between switches (this VLAN is part of the interconnection).

There is following error on the switch2 (Gi0/25 is where server is connected, Gi0/30 is the interconnection)

*Jun  1 16:18:23.182: %SW_MATM-4-MACFLAP_NOTIF: Host 1cc1.de7a.04b6 in vlan 1111 is flapping between port Gi0/25 and port Gi0/30 
*Jun  1 16:18:45.093: %SW_MATM-4-MACFLAP_NOTIF: Host 1cc1.de7a.04b6 in vlan 1111 is flapping between port Gi0/30 and port Gi0/25 
*Jun  1 16:18:56.031: %SW_MATM-4-MACFLAP_NOTIF: Host 1cc1.de7a.04b6 in vlan 1111 is flapping between port Gi0/25 and port Gi0/30 
*Jun  1 16:19:15.141: %SW_MATM-4-MACFLAP_NOTIF: Host 1cc1.de7a.04b6 in vlan 1111 is flapping between port Gi0/25 and port Gi0/30 
*Jun  1 16:19:23.479: %SW_MATM-4-MACFLAP_NOTIF: Host 1cc1.de7a.04b6 in vlan 1111 is flapping between port Gi0/30 and port Gi0/25 
*Jun  1 16:19:45.616: %SW_MATM-4-MACFLAP_NOTIF: Host 1cc1.de7a.04b6 in vlan 1111 is flapping between port Gi0/30 and port Gi0/25 

when checking configuration you can see that both switches has learned 1cc1.de7a.04b6 MAC address

NLS-PDC-SW2>show mac address-table vlan 1111 
          Mac Address Table
-------------------------------------------
Vlan    Mac Address       Type        Ports
----    -----------       --------    -----
1111    1cc1.de7a.046a    DYNAMIC     Gi0/26
1111    1cc1.de7a.04b6    DYNAMIC     Gi0/25
Total Mac Addresses for this criterion: 23

NLS-PDC-SW1>show mac address-table vlan 1111 
          Mac Address Table
-------------------------------------------
Vlan    Mac Address       Type        Ports
----    -----------       --------    -----
1111    1cc1.de7a.04b6    DYNAMIC     Gi0/25
Total Mac Addresses for this criterion: 24
NLS-PDC-SW1>

checking the modprobe file from both servers I've found that on server2 (which contain 1cc1.de7a.04b6)

alias bond0 bonding
options bond0 miimon=100

and on server1 (which contain 1cc1.de7a.046a)

alias bond0 bonding
options bond0 miimon=100 mode=1

I'm really confused with the needed configuration. Can you please suggest?

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A quick search on "sw_matm-4-macflap_notif" leads me to think that this is a Cisco routing configuration problem and not server configuration problem. I'd normally suggest serverfault.com, but this is a highly localized problem, likely specific to your particular configuration and I doubt you'll get much satisfaction there. I suggest you contact Cisco support and read their docs on HOWTO do what you want. –  msw Jul 31 '13 at 11:48
1  
I believe you are missing the bonding on the switch side. You have the ports assigned to a VLAN but they are working independently instead of bonding. –  BitsOfNix Jul 31 '13 at 11:48
    
@msw, we have already verified the switch configuration. It seems that it is configured OK. –  user1977050 Jul 31 '13 at 12:05
    
@AlexandreAlves - how the bonding on 2 separate switches are related? is there such option (I'm not familiar with such option). –  user1977050 Jul 31 '13 at 12:05

1 Answer 1

Your problem is mode 0, which causes all NICs in the bond to use the same MAC address. Because you have not specified a mode on the first server, you get the default, which is 0.

In mode 0, all interfaces use the same MAC address, and all interfaces actively transmit. This requires that the switch be configured for link aggregation.

Unless you have a Cisco Nexus switch, it is impossible for you to have configured 2 switches to support link aggregation between the switches. Only Nexus switches support it.

Your options are to either switch to a mode that doesn't require switch support (i.e., mode 1, like your other server that is not causing a problem) or connect both NIC's to the same switch and set up ling aggregation on the switch.

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