* B (Encapsulation at source and destination):Overlay networks encapsulate payloads inside another protocol (e.g. VXLAN, GRE, MPLS), adding headers that enable separation from the underlay network while introducing minor overhead due to encapsulation.
Other options explained:
* A: Describes underlay behavior.
* C: Overlay encapsulation occurs independently of L3/L4 reliability.
* D: NAT or VRF are isolation mechanisms but not how overlays function.

* B (RPVST+ - Rapid Per VLAN Spanning Tree Plus): Provides fast convergence while blocking redundant paths to prevent loops - fail closed behavior under failure scenarios.
* C (MST - Multiple Spanning Tree): Provides loop prevention and isolates failures to specific instances (VLANs), maintaining fail closed protection.
Why other options are incorrect:
* A: EIGRP is a routing protocol; does not operate at Layer 2 to provide fail-closed loop protection.
* D: L2MP (Layer 2 Multipathing) allows multiple active links but requires additional loop prevention mechanisms.
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GLOP addressing is defined in RFC 2770. It assigns globally unique multicast addresses based on an organization's ASN by mapping the 16-bit ASN into the middle two octets of the 233.0.0.0/8 address space.
* 233.0.0.0/8 is specifically reserved for GLOP addressing.
* The uniqueness of the address is derived from the assigned ASN.
Why other options are incorrect:
* A: 232.0.0.0/8 is SSM address space.
* C: 239.0.0.0/8 is for administratively scoped multicast.
* D: 224.0.0.0/24 is reserved for local multicast (link-local scope).
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#Explanation:
* B: Segmentation isolates network zones (e.g., separating finance from guest access), limiting lateral movement after a breach.
* E: Microperimeters apply security controls closer to the application or workload, providing granular control and defense in depth.
Other options:
* A: Microzoning is not a widely defined or standard practice in network security.
* C: Domain fencing is not a standard security term or methodology.
* D: Virtualization is a technology, not a security architecture.