By default, QFX10000, QFX5100, QFX5110, QFX5200, and QFX5210 switches that act as spine and
leaf devices in an EVPN-VXLAN overlay network implement the core isolation feature. If one of these
QFX switches loses all of its EVPN internal BGP (IBGP) peering sessions, the core isolation feature,
working in conjunction with Link Aggregation Control Protocol (LACP), automatically brings down all
Layer 2 Ethernet Switch Identifier (ESI) link aggregation group (LAG) interfaces on the switch. In some
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situations, this feature produces an undesired outcome that you can prevent by disabling the feature
with the no-core-isolation configuration statement at the [edit protocols evpn] hierarchy level.
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