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Dshell Troubleshooting Troubleshooting Source Learning
page 3-8 OmniSwitch Troubleshooting Guide September 2005
000001f3
Total L2 SA entry amount = 1
Both of the MAC addresses are learned in the correct VLANs on the right NI.
Now, if device A is trying to communicate to device B then the next thing to look for is the destination
MAC address table. This is to verify that the destination MAC address table has the information about the
device B.
Working: [Kernel]->slcDumpL2DA 8,0
Index Mac Address Vlan GlobalPort 4-words content
-------+-------------------+------+-----------+---------------------------------
----
0x3004 00:20:da:00:70:04 1 0 00010020 da007004 c0004000
00024000
0x3538 00:10:a4:b5:b5:38 114 499 00720010 a4b5b538 00180000
1f057f3
So the entry do show up for the destination device.
Similarly for bidirectional traffic the entry should show up on slot 16.
Working: [Kernel]->slcDumpL2DA 16,0
Index Mac Address Vlan GlobalPort 4-words content
-------+-------------------+------+-----------+---------------------------------
----
0x3004 00:20:da:00:70:04 1 0 00010020 da007004 c0004000
00024000
0x371b 00:c0:4f:12:f7:1b 114 250 007200c0 4f12f71b 00180000
1f05b3a
So, the two devices should be able to communicate.
The L2SA and L2DA tables will be different for each slot. L2SA table will be based on the MAC address
learned on that slot. This will not be synchronized to all the other modules. Only the CMM will know
about it. When the request comes in from device A for device B, first a lookup is done on the local L2SA
and L2DA tables to see if there is a matching entry. If there is no matching entry then a request is sent on
the BBUS to all the other Coronados, if any Coronado has the matching entry in its L2SA table it responds
back with the Global port number of that entry. L2DA table is updated on the originating Coronado and
the packet is forwarded to the Global port to reach the destination.
If no other Coronado responds back to the request then the packet is sent over the flood queue to all the
other Coronado to be flooded out of the ports in the same VLAN. If a device responds back on the flooded
request, L2SA for that NI is updated and the Global port number is send to the originating device using the
same lookup as the response will be a unicast packet.
To see Source learning in action on an NI, set the debug level higher (levels are 1-6):
-> Sl_NiDebug=4
To see Source Learning in action on a CMM, set the debug level higher (levels are 1-6):
-> Sl_CmmDebug=5
To view the messages on the console, disable systrace:
-> Sl_no_systrace=1
The following is a sample output: