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Intermittent packet loss on DCAv1 Interconnect switches (Brocade 8000)

Problem 

There is Intermittent packet loss on DCAv1 Interconnect switches.

Cause

DCA (Data Computing Appliance) uses Brocade 8000 as interconnect switches for inter-rack communication when more than one rack is present. Interconnect switches in each rack use Brocade proprietary Link Aggregation Protocol (LAG) to connect to aggregation switches which are also Brocade 8000.
 
There is a known problem of Brocade LAG that frames could be dropped by the switch and in the worst case the LAG ceasing to function. The problem takes place when a particular sequence of events occurs involving two or more Brocade 8000s connected via Brocade trunking (details below) – that coupled with mac addresses aging out of different 8000s at different times – specifically when macs are aged out of some Brocade 8000s but not others.

Solution

To turn off mac aging on a Brocade 8000, use the following steps

1. Login to Brocade 8000 
2. At FOS prompt, enter the Ethernet side of switch
                    Brocade_8000:admin> cmsh
                    Brocade_8000#
3. Enter configuration mode
                    Brocade_8000#config t
                    Enter configuration commands, one per line.  End with CNTL/Z.
                    Brocade_8000(config)#
4. Disable the mac address aging time (default is 5 minutes)
                    Brocade_8000(config)#mac-address-table aging-time 0
5. Verify mac address aging time
                    Brocade_8000(config)#do sho mac-address-table aging-time
                    MAC Aging-time : 0 seconds

Notes 

if you still see Packet dropping issues in switches with the correct mac address aging setting, please create a case with Customer Service for investigation.

Workaround

Turn off mac aging to avoid having macs aged out of the forwarding tables.


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