.. _example_protocols_bgp_neighbor_allowas-in:

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Allowas-In
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This scenario demonstrates how to configure the allowas-in feature for a BGP neighbor.
By default, BGP rejects routes that contain its own AS number in the AS_PATH to prevent loops.
The allowas-in feature allows a router to accept routes with its own AS in the path up to a specified number of occurrences,
which is useful in hub-and-spoke eBGP topologies where the same AS may appear multiple times legitimately.

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Test eBGP - Allowas-in enabled
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Description
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Test to verify that allowas-in allows routes with own AS in the AS_PATH.
DUT0 is configured with allowas-in number 3.
DUT0 should now accept the route even though it contains its own AS number.

Scenario
========

.. include:: allowas-in/testebgp-allowas-inenabled

.. raw:: html

  <hr>

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Test eBGP - Allowas-in disabled (default)
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Description
===========

Test to verify that by default BGP rejects routes containing its own AS in the AS_PATH.
DUT1 prepends DUT0's AS (100) to the AS_PATH, simulating a route that has traversed DUT0's AS.
DUT0 should reject this route because it contains its own AS number.

Scenario
========

.. include:: allowas-in/testebgp-allowas-indisabled(default)

.. raw:: html

  <hr>