| Technology / Role | Elected item | Primary criterion | Tie-break | Higher / Lower? |
|---|---|---|---|---|
| OSPF | Router-ID | Manual `router-id` if set | Highest loopback IP, else highest active int IP | Highest |
| DR / BDR | Highest priority | Highest Router-ID | Highest | |
| EIGRP | Router-ID | Highest loopback IP | Highest active phys IP | Highest |
| STP / RSTP | Root Bridge | Lowest bridge ID (priority + MAC) | Lower MAC | Lowest |
| PIM-SM | Designated Router | Highest PIM priority | Highest interface IP | Highest |
| Bidir-PIM | Designated Forwarder | Highest DF priority | Highest interface IP | Highest |
| IGMP / MLD | Designated Querier | Lowest source IP | — | Lowest |
| HSRP | Active Router | Highest priority | Highest interface IP | Highest |
| VRRP | Master Router | Highest priority | Highest interface IP | Highest |
| GLBP | Active Virtual Gateway | Highest priority | Highest interface IP | Highest |
| IGMP Snooping | Querier (switch) | Lowest IP among switches | — | Lowest |