Layer 2 VPN Pseudowire Components - Exam 400-201 - Cisco CCIE Service Provider Written Exam

Layer 2 VPN Pseudowire Components


Which three Layer 2 VPN pseudowire components are true? (Choose three.)



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A. B. C. D. E. F.


Layer 2 VPN pseudowires are used to connect two sites over a Layer 2 infrastructure, allowing the transmission of Ethernet frames between the sites as if they were on the same LAN. A pseudowire is essentially a point-to-point connection between two provider edge (PE) routers. Here are the explanations for the three true components:

A. Attachment Circuit: This refers to the physical or logical interface on a CE (Customer Edge) device that connects to the provider network. The attachment circuit is the source or destination of the Layer 2 traffic that will be transported over the pseudowire.

D. Virtual Circuit Label: This is a label used to identify a pseudowire. It is used by the provider routers to forward traffic from one end of the pseudowire to the other. Each pseudowire has a unique virtual circuit label assigned to it.

E. Pseudowire Identifier: This is a unique identifier used to identify a pseudowire. It is used by the control plane protocols that set up and maintain the pseudowire. The pseudowire identifier is used by the PE routers to determine which pseudowire a received packet belongs to.

The other components mentioned in the question are not Layer 2 VPN pseudowire components:

B. Bandwidth Requirement: While bandwidth requirements are important considerations for designing a network, they are not a component of a Layer 2 VPN pseudowire.

C. Route Distinguisher and F. Route Target: These are components of a VPN route target (RT), which is used to control the distribution of VPN routes between different VPNs. While a Layer 2 VPN may use VPN RTs, they are not specific components of a pseudowire.