Mutual redistribution between different routing protocols can cause routing loops and suboptimal routing due to:
Route feedback loops (routes being re-imported back into the originating protocol).
Inconsistent administrative distances (AD) leading to selection of suboptimal paths.
Two key mechanisms avoid these issues:
A. Administrative Distance (AD) manipulation: Ensures that one protocol is consistently preferred over the other when duplicate routes exist.
C. Route tagging: Assigns tags to redistributed routes to identify the source of the route and prevent re-importation (looping) into the originating protocol.
These methods align with CCDE v3.1 principles for multi-protocol control plane design and stability.
Why other options are incorrect:
B and F: Matching routes or process IDs do not directly prevent loops or suboptimal routing.
D is a duplicate of C.
E: Filtering helps but is reactive, not a comprehensive prevention mechanism.
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