When implementing VPLS on Cisco IOS XR routers, the VPLS PW neighbors can be statically defined under which configuration mode?

Question

Options

• Abridge group
• Bbridge-domain
• Cvfi
• Dmpls ldp
• El2transport

• A
  15% (4)
• B
  4% (1)
• C
  70% (19)
• D
  7% (2)
• E
  4% (1)

Explanation

In Cisco IOS XR, VPLS pseudowire neighbors are defined under the VFI (Virtual Forwarding Instance) configuration mode, which exists specifically to handle the signaling and neighbor relationships for VPLS service. Within the VFI stanza, you specify remote PE neighbors and their corresponding pseudowire IDs, enabling the VPLS mesh or hub-and-spoke topology.

Why the distractors are wrong:

• A (bridge group) - A bridge group is merely an organizational container that groups bridge-domains together; no PW configuration happens here.
• B (bridge-domain) - The bridge-domain is the parent of the VFI and handles local attachment circuits (ACs), but PW neighbors are delegated to the VFI child configuration block.
• D (mpls ldp) - This mode configures LDP globally (transport label distribution), not VPLS service endpoints.
• E (l2transport) - This mode is used for point-to-point Layer 2 cross-connects (VPWS/Xconnect), not for multipoint VPLS neighbor definitions.

Memory tip: Think VFI = "Virtual Fabric of Interconnections" - it's the logical mesh fabric for VPLS, so naturally it's where you stitch in your remote neighbors. If you remember that VFI is the multipoint construct (vs. l2transport for point-to-point), you'll never confuse C and E on the exam.

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