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Difficulty: EasyRouting Concepts and Dynamic Routing Protocols

A network administrator is reviewing a router's configuration where both a static route and an OSPF dynamic routing protocol offer paths to the exact same destination subnet. Which attribute does the router evaluate first to determine which routing source is more trustworthy and should be installed into the active routing table?

  1. Administrative distanceAnswer
  2. B
    Metric value
  3. C
    Port protocol mapping
  4. D
    PAT overload translation table

Answer

Administrative distance is evaluated first when comparing routes to the same destination from different routing protocols or static configuration.
Administrative distance measures the trustworthiness of a routing information source. When a router receives route information for an identical destination prefix from different sources, it selects the source with the lowest administrative distance to populate the active routing table.

Step-by-Step Solution

1
Identify the routing sources competing for entry in the routing table.
The router has learned paths to the same destination via both static routing and OSPF dynamic routing.
When multiple sources provide routes to identical destination networks, a selection tie-breaker mechanism is required.
2
Determine the primary criterion used to rate protocol trustworthiness.
Administrative Distance (AD) assigns a numerical believability rating to each routing source (e.g., Static = 1, OSPF = 110).
Lower Administrative Distance values take precedence over higher values before internal protocol metrics are considered.

Key Concept

Administrative Distance vs. Metric in Route Selection
Estimated Time:45s
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Topics

Routing Concepts and Dynamic Routing Protocols

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