I have 3 x670 switches stacked together (with ethernet ports). All 3 are running with an Advanced Edge License. We currently have ospf running (but with only a few vlans, that allows us to get by with an Advanced Edge license). We want to enable PIM fro multicast routing, however in order to do that you need to have a Core license. My question is on which switches do I need to have a Core license installed? Stack Topology is a Ring Active Topology is a Ring Node MAC Address Slot Stack State Role Flags ------------------ ---- ----------- ------- --- *00:04:96:6d:65:87 1 Active Master CA- 00:04:96:6d:65:6d 2 Active Backup CA- 00:04:96:8b:f5:8b 3 Active Standby CA- * - Indicates this node Flags: (C) Candidate for this active topology, (A) Active Node (O) node may be in Other active topology Stack MAC in use: 02:04:96:6d:65:87 Node Slot Alternate Alternate MAC Address Cfg Cur Prio Mgmt IP / Mask Gateway Flags Lic ------------------ --- --- ---- ------------------ --------------- --------- --- *00:04:96:6d:65:87 1 1 Auto CcEeMm-Nn -- 00:04:96:6d:65:6d 2 2 Auto CcEeMm-Nn -- 00:04:96:8b:f5:8b 3 3 Auto CcEeMm-Nn -- * - Indicates this node Flags: (C) master-Capable in use, (c) master-capable is configured, (E) Stacking is currently Enabled, (e) Stacking is configured Enabled, (M) Stack MAC in use, (m) Stack MACs configured and in use are the same, (i) Stack MACs configured and in use are not the same or unknown, (N) Enhanced protocol is in use, (n) Enhanced protocol is configured, (-) Not in use or not configured License level restrictions: (C) Core, (A) Advanced edge, or (E) Edge in use, (c) Core, (a) Advanced edge, or (e) Edge configured, (-) Not in use or not configured Do I just need 2, one for Master and the other for Backup, in case Slot 2 becomes Master? What if I want all 3 switches to be Master. Do I need to put a Core license on all 3? Thanks in advance! -B