Examkin

Soru

Zorluk: OrtaFirst Hop Redundancy Protocols (HSRP and VRRP)

Two Layer 3 switches, Core-1 and Core-2, provide default gateway redundancy for hosts in VLAN 30 (10.30.0.0/2410.30.0.0/24). Core-1 is configured with physical interface IP address 10.30.0.2/2410.30.0.2/24 and Core-2 with 10.30.0.3/2410.30.0.3/24. A network administrator enters the configuration command `standby 30 ip 10.30.0.2` on Core-1's VLAN 30 interface. Which outcome occurs when this command is executed?

  1. The router rejects the command because HSRP does not allow the virtual IP address to match an IP address assigned to a physical interface.Cevap
  2. B
    The command is accepted, and Core-1 automatically raises its HSRP priority to 255 to become the permanent Active router.
  3. C
    The command is accepted into the running configuration, but Core-1 logs duplicate IP address conflict messages continuously.
  4. D
    The router accepts the command and dynamically derives a virtual MAC address using Core-1's physical burned-in MAC address.

Cevap

The command is rejected because HSRP virtual IP addresses cannot match any physical interface IP address configured on the router.
Cisco IOS/IOS-XE enforces a fundamental operational rule in HSRP: the virtual IP address must be unique within the subnet and cannot match the physical IP address of any router interface in the HSRP group. Attempting to assign an interface's physical IP address as the HSRP virtual IP results in an immediate CLI error rejecting the command.

Adım Adım Çözüm

1
Analyze the HSRP virtual IP address configuration rule.
In Hot Standby Router Protocol (HSRP v1 and v2), the virtual IP address must be an unused IP address within the subnet assigned to the interface.
Assigning an existing physical interface IP address as the virtual IP would cause internal IP routing conflicts and ARP table ambiguities on the local router.
2
Compare HSRP behavior with VRRP.
While Virtual Router Redundancy Protocol (VRRP) allows a router to act as the IP address owner by assigning its physical IP address as the virtual IP (setting priority to 255), HSRP explicitly forbids this.
Understanding protocol implementation differences is essential for gateway redundancy administration.
3
Determine the CLI execution result.
Entering `standby 30 ip 10.30.0.2` on an interface already configured with physical IP 10.30.0.210.30.0.2 causes Cisco IOS to return a command syntax/validation error and reject the entry.
The CLI parser validates the virtual IP against existing interface address configurations immediately upon entry.

Anahtar Kavram

HSRP Virtual IP Address Assignment Restrictions
Bu soruyu puanla

Konular

First Hop Redundancy Protocols (HSRP and VRRP)

Bu konudan daha fazla soru