Huawei BGP AS_PATH filters use regular expressions to match autonomous system sequences contained in BGP routing updates.
Option A uses 00$, which matches an AS_PATH ending in 00. The provided path ends in AS 300, so the expression matches.
Option B uses .*, which matches any sequence of characters, including the entire AS_PATH. Consequently, this expression would deny all matching BGP routes.
Option C matches the substring 200, which appears in the middle of the AS_PATH.
Option D uses 00.*30, which matches a sequence beginning with 00, followed by any number of characters, and subsequently 30. The supplied AS_PATH satisfies this expression.
All four expressions match the specified path and can deny it. However, option B is excessively broad for selective production filtering.
HCIP-Datacom-Advanced Routing & Switching Technology V1.0 Training Material.pdf
================
