Four routers on a shared Layer 2 Ethernet segment are configured to run OSPF using the broadcast network type. The administrator configures the OSPF interface priorities and router IDs as follows:
| Router | OSPF Interface Priority | Router ID |
|---|---|---|
| Router A | 1 | 192.168.1.10 |
| Router B | 2 | 10.10.10.1 |
| Router C | 0 | 10.20.20.20 |
| Router D | 2 | 10.10.10.2 |
Assuming all routers boot simultaneously and form adjacencies, which router will be elected as the Designated Router (DR) for this multi-access segment?
- Router DCevap
- BRouter C
- CRouter B
- DRouter A
Cevap
Router D will be elected as the Designated Router because it shares the highest priority (2) and has a higher Router ID than Router B.
In OSPF broadcast networks, the Designated Router election evaluates highest interface priority first. Routers with priority 0 are completely excluded. Routers B and D tie with a priority of 2. To break the tie, OSPF selects the router with the highest Router ID. Comparing 10.10.10.2 (Router D) against 10.10.10.1 (Router B), Router D has the higher Router ID and is elected DR.
Adım Adım Çözüm
Anahtar Kavram
OSPF Designated Router (DR) election criteria (Highest Priority > Highest Router ID; Priority 0 excludes).
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