We want to replace 3 D-Link non manageable switch with the HP manageable switch. Currently these unmanageable switch is connected with Cisco Catalyst 2960 Switch with three uplink to Cisco switch. I want to connect three HP switch to new 2 HP Core switch working as Active-Active with 10 GBPS uplink between them. As per the HP Chat, their recommendation is to have 3 HP Switch model 2920-48 G J9728A. The core switch suggest here by local supplier is HP 5820-24XG-SFP+Switch. I don't have any idea about how many transceiver I need to connect between them. Please advice.