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Zorluk: Çok zorFloating Static Routes

An enterprise edge router receives a primary internal route for destination prefix 10.50.0.0/1610.50.0.0/16 via Internal EIGRP (Administrative Distance 90) and a primary default route for 0.0.0.0/00.0.0.0/0 via external BGP (eBGP, Administrative Distance 20). A network administrator needs to configure floating static routes to serve as automatic failover backups for both destinations. Which TWO configuration statements correctly specify the Administrative Distance requirements for these static routes to operate strictly as floating backups? (Select TWO.)

  1. The floating static route backing up destination 10.50.0.0/1610.50.0.0/16 must be configured with an Administrative Distance value greater than 90.Cevap
  2. The floating static route backing up destination 0.0.0.0/00.0.0.0/0 must be configured with an Administrative Distance value greater than 20.Cevap
  3. C
    The floating static route backing up destination 0.0.0.0/00.0.0.0/0 should use the default static Administrative Distance of 1 so it takes precedence during failure scenarios.
  4. D
    The floating static route backing up destination 10.50.0.0/1610.50.0.0/16 should be configured with an Administrative Distance of 85 to prevent route flapping between routing processes.

Cevap

The floating static route for 10.50.0.0/16 must have an Administrative Distance greater than 90, and the floating static route for 0.0.0.0/0 must have an Administrative Distance greater than 20.
Cisco IOS routing table selection prioritizes routes with lower Administrative Distance (AD). For a static route to function as a 'floating' backup, its AD must be manually configured to a value higher than that of the active primary routing protocol (Internal EIGRP AD 90, eBGP AD 20). This ensures the static route remains untracked in the routing table until the primary route's AD source is lost.

Adım Adım Çözüm

1
Identify the default Administrative Distance (AD) of the primary routing protocols.
Internal EIGRP has a default AD of 90; external BGP (eBGP) has a default AD of 20.
Cisco IOS selects routes with the lowest Administrative Distance when multiple sources provide routes to the same destination.
2
Determine the required AD for floating static backup routes.
Backup route AD for EIGRP must be > 90 (e.g., 95). Backup route AD for eBGP must be > 20 (e.g., 25).
A floating static route must remain out of the routing table while the primary protocol is active, which requires the static route to have a higher numerical AD than the primary route.

Anahtar Kavram

Floating Static Route Administrative Distance Requirements
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