Addressing
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... Hierarchical routing requires that aggregation boundaries for the
addressing information be formed along some hierarchy. As a result,
many exceptions will be injected into the routing system in the
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... that inject the routing information. Aggregation of addressing
information (via CIDR) could reduce the cost, as it allows an
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... Internet routing system with non-
aggregatable addressing information; however they have other
drawbacks which may prove awkward in certain situations.
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