Examkin

Soru

Zorluk: OrtaOSPFv2 Network Types and DR/BDR Selection

A network administrator evaluates an OSPFv2-enabled router interface on a multiaccess Ethernet network and issues the following Cisco IOS command:

text
Router1# show ip ospf interface GigabitEthernet0/1
GigabitEthernet0/1 is up, line protocol is up
Internet Address 192.168.10.1/24, Area 0
Process ID 1, Router ID 10.1.1.1, Network Type BROADCAST, Cost: 1
Trans Delay is 1 sec, State DROTHER, Priority 0
Designated Router (ID) 10.4.4.4, Interface address 192.168.10.4
Backup Designated Router (ID) 10.3.3.3, Interface address 192.168.10.3
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5

Which two statements accurately describe the operational status and election behavior of this router on the segment? (Choose two.)

  1. The router is completely ineligible to be elected as Designated Router (DR) or Backup Designated Router (BDR) because its interface priority is set to 0.Cevap
  2. If the active Designated Router (10.4.4.4) fails, the Backup Designated Router (10.3.3.3) will be promoted to Designated Router while this router remains a DROTHER.Cevap
  3. C
    If the active Designated Router fails, this router will automatically claim the Backup Designated Router role because its priority value is 0.
  4. D
    Modifying the interface priority from 0 to 255 will immediately cause this router to preempt the current Designated Router.
  5. E
    Reconfiguring the network type on this interface to POINT_TO_POINT will trigger an election for a single Designated Router without electing a BDR.

Cevap

The correct statements are that the router is completely ineligible for DR/BDR election due to an interface priority of 0, and that if the active DR fails, the active BDR will be promoted to DR while this router remains a DROTHER.
In OSPFv2 broadcast multiaccess networks, setting an interface priority to 0 makes the router completely ineligible for Designated Router (DR) or Backup Designated Router (BDR) roles, forcing it into the DROTHER state. Furthermore, when an active DR fails, the existing BDR is promoted to DR. Because this router's priority is 0, it cannot participate in the election for the replacement BDR and remains a DROTHER.

Adım Adım Çözüm

1
Analyze interface priority settings from the command output.
The interface priority is configured as Priority 0.
In OSPFv2, an interface priority of 0 signifies that the router is ineligible to participate in DR or BDR elections.
2
Determine the router's current state and election behavior.
The state is DROTHER, and it will remain in this state even if the active DR fails.
Upon DR failure, the current BDR (10.3.3.3) takes over as DR. A new BDR election occurs among eligible routers (priority > 0). Since this router has priority 0, it cannot become the new BDR.
3
Evaluate preemption and alternative network types.
OSPF DR/BDR elections are non-preemptive, and Point-to-Point links suppress DR/BDR elections entirely.
Modifying priorities does not trigger preemption on broadcast links, and changing to Point-to-Point eliminates DR/BDR roles entirely.

Anahtar Kavram

OSPFv2 DR/BDR Election Rules and Priority 0 Ineligibility
Bu soruyu puanla

Konular

OSPFv2 Network Types and DR/BDR Selection

Bu konudan daha fazla soru