Which BGP attribute is used to prevent routing loops within an IBGP full mesh?
- MED
- IBGP split-horizon rule
- LOCAL_PREF
- AS_PATH
Explanation: According to the sources, the IBGP split-horizon rule is the primary mechanism used to prevent routing information loops within an Autonomous System (AS). This rule states that routing information received through an IBGP session is never forwarded to another IBGP neighbor, but only toward EBGP neighbors. To ensure that all BGP-speaking routers within the AS have consistent routing information while adhering to this rule, a full mesh of IBGP sessions is required. While the AS_PATH attribute is used to detect loops between different autonomous systems, it is not modified during internal propagation and therefore cannot prevent loops within the same AS.
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