Explains how route summarization simplifies route tables by replacing multiple specific addresses with a single address in ACI environments.
Route summarization is a network optimization technique that
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simplifies route tables by replacing many specific addresses with a single address
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enables routes to be shared efficiently among border leaf switches and their neighboring switches, and
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reduces the scale requirements of the fabric through route filtering and aggregation.
Route summarization forms in ACI
Two forms of route summarization are supported in ACI beginning in the Cisco APIC 5.2(4) release:
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Route Summarization at the L3Out External EPG Level: This configuration of route summarization at the L3Out External EPG Level allows route summarization towards external L3Out peers only.
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Route Filtering and Aggregation at the VRF Level: Beginning in the Cisco APIC 5.2(4) release, Cisco APIC also provides option to perform route filtering and aggregation of routes that are advertised in a fabric to reduce the scale requirements of the fabric. This feature is configured at the VRF level. Enabling route summarization at the VRF level helps to achieve summarization of routes into the ACI fabric, as well as towards external BGP L3Out peers.
Route summarization example
For example, 10.1.1.0/24, 10.1.2.0/24, and 10.1.3.0/24 can be replaced with 10.1.0.0/16.