your SFP's need to have the DOMhave a look on the SFP data sheet:http://www.cisco.com/en/US/partner/prod/collateral/modules/ps5455/ps6577/product_data_sheet0900aecd8033f885.htmlexemple:GLC-SX-MM is without DOMGLC-SX-MMD with DOMfor your GLC-ZX-SM, yo...