Below are all the Specific reasons why end-users may see error messages appearing on the core:
Noticed that one of the cores is not sending the socket information on the SMLT packets headers which is the reason why you may be getting the socket read errors on a core switch.
sometimes the "SMLT-VIRTUAL-BMAC" is not configured the same on both the core switches; this configuration is not correct. The "virtual-bmac" should be configured the same on both IST peer switches.
Example of BMAC configuration being incorrect:
Core-A: spbm 1 smlt-virtual-bmac 00:49:01:45:00:01
Core-B: spbm 1 smlt-virtual-bmac 00:49:01:45:00:02
Other possible reasons for the error are:
1. MLT / SMLT is configured on one switch and not configured on switch at the other end of the link.
2. Invalid VLAN configuration on the port(s) and MLT/SMLT.
Note: It is recommended to properly follow the configuration guide for MLT / SMLT configurations strictly.