Here are the results of your search through the public section of the IEEE Standards OUI database report for ECI Telecom:
00-02-0E (hex) ECI Telecom, Ltd., NSD-US 00020E (base 16) ECI Telecom, Ltd., NSD-US 1300 Omega Dr. Pittsburgh PA 15205 UNITED STATES
00-06-5F (hex) ECI Telecom - NGTS Ltd. 00065F (base 16) ECI Telecom - NGTS Ltd. 30 Hasivim St. Petah-Tikva 49130 ISRAEL
00-16-FA (hex) ECI Telecom Ltd. 0016FA (base 16) ECI Telecom Ltd. 30 Hasivim St. Petah Tikva 49133 ISRAEL
00-20-8F (hex) ECI TELECOM LTD. 00208F (base 16) ECI TELECOM LTD. HASIVIM ST. 30, PETACH-TIKVA 49133 ISRAEL
Your attention is called to the fact that the firms and numbers listed may not always be obvious in product implementation. Some manufacturers subcontract component manufacture and others include registered firms' OUIs in their products.