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Difficulty: MediumIPv6 Static Routing

Complete the Cisco IOS command by entering the missing administrative distance value to configure a floating static route.

Answer:An engineer is configuring a backup IPv6 static route to network 2001:db8:40::/64 via next-hop 2001:db8:10::2. The route must remain inactive in the routing table unless the primary OSPFv3 route (administrative distance 110) fails.

Complete the command below by filling in a valid administrative distance value in 【111】:

`Router(config)# ipv6 route 2001:db8:40::/64 2001:db8:10::2 【111】`

Answer

Any integer from 111 through 254 (for example, 130) that is greater than the OSPFv3 administrative distance of 110.
A floating static route requires an Administrative Distance (AD) higher than the routing protocol it backs up. Since OSPFv3 has a default AD of 110, any integer value between 111 and 254 (such as 120, 130, or 150) placed at the end of the `ipv6 route` command correctly configures the floating static route.

Step-by-Step Solution

1
Identify the primary route's Administrative Distance (AD).
The primary route uses OSPFv3, which has a default AD of 110.
Floating static routes rely on a higher AD than the active routing protocol so they are only installed when the primary route fails.
2
Determine the valid range for the floating static route AD.
The AD must be strictly greater than 110 and less than 255 (valid Cisco IOS AD range for static routes is 1–254).
An AD of 255 makes a route unroutable/untrustworthy, while an AD of 110 or less would cause the static route to preempt or equal-cost load-share with OSPFv3.
3
Place the AD parameter in the Cisco IOS IPv6 static route syntax.
The syntax is `ipv6 route <prefix/length> <next-hop> [administrative-distance]`.
The final optional position in the command specifies the administrative distance.

Key Concept

IPv6 Floating Static Route Administrative Distance Configuration
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Topics

IPv6 Static Routing

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