When an enterprise router receives an IP packet, it executes a standardized path selection hierarchy to determine the optimal route for packet forwarding. Place the following route evaluation steps in the correct sequential order from first decision criteria to last.
- 1Filter all candidate destination entries in the routing table to find routes that match the packet's destination IP address.
- 2Select the route with the longest prefix length (most specific subnet mask) among all matching candidates.
- 3Compare the Administrative Distance (AD) of routes sharing the exact same prefix length from different routing sources and select the lowest AD.
- 4Compare protocol-specific metrics for routes with matching prefix lengths and equal Administrative Distance, selecting the route with the lowest metric cost.
- 5Install multiple identical paths into the routing table to perform Equal-Cost Multi-Path (ECMP) load balancing if prefix length, AD, and metric are all identical.
Cevap
The correct sequence for router path selection is: 1) Filter matching routing table entries, 2) Select the longest prefix match, 3) Select the route with the lowest Administrative Distance, 4) Select the route with the lowest metric, and 5) Install equal-cost paths for Equal-Cost Multi-Path (ECMP) load balancing.
The correct order follows the standard IP routing decision tree: the router first filters candidate routes, selects the route with the Longest Prefix Match (LPM), breaks ties between different protocols using Administrative Distance (AD), breaks ties within the same protocol using metric cost, and finally utilizes Equal-Cost Multi-Path (ECMP) if all parameters are completely identical.
Adım Adım Çözüm
Anahtar Kavram
Router Path Selection Hierarchy (LPM -> AD -> Metric -> ECMP)