Serial Number not been reported in Ops Centre Update 4 (12.1.4.2319)

Hi,

I have a number of assets whose serial numbers are not been reported and therefore I can't get them to register in MOS.  I ran a report and get the following: ( removed host names for security reasons)

Filters:

Asset Name,Model,Serial Number

<hostname>,Netra X4200 M2,0000000000                     

<hostname>,SPARC-ENTERPRISE-T5220,-

<hostname>,SPARC T4-2,1202BDY4DA

<hostname>,SUN NETRA X4250,To Be Filled By O.E.M.

<hostname>,SPARC T4-2,1233BDY48D

<hostname>,-,-

How can I resolve this?

Regards,

Ed