You are asked to design a Layer 2 VPN service for a service provider network that supports Ethernet and ATM transport.Which two Layer 2 VPN technologies will meet this requirement? (Choose two.)
A.
LDP-signaled VPLS, using draft martini encapsulation
B.
BGP-signaled VPLS, using the RFC 4448 Layer 2 frame format
C.
LDP Layer 2 circuit, using the RFC 4448 Layer 2 frame format
D.
BGP Layer 2 VPN, using draft-Martini encapsulation
C, D
Layer 2 VPNs Are Point to Point
Border Gateway Protocol (BGP) Layer 2 VPNs and LDP Layer 2 circuits are point to point in nature and
support Ethernet, ATM, Frame Relay, Point-to-Point Protocol (PPP), and Cisco’s High-Level Data Link Control
(Cisco HDLC). Even though Ethernet media can be used between PE and CE devices, only two CE devices
can interact over a single emulated Layer 2 circuit or virtual LAN (VLAN). Although this behavior works
well as it is, some customers prefer to have their Ethernet media behave like Ethernet so that more than
two hosts or routers can interact over the Layer 2 circuit. This need on behalf of the customer, and other
factors, is what led to the development of VPLS.
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Option A: could be right
Option B: wrong – rfc 4448 is ldp signalled.
Option C: right
Option D: wrong – bgp used kirti/compella draft while ldp used martini/rosen draft
The correct possibilities looks A and C.
But the question confuses by asking “Which two Layer 2 VPN technologies” as there are only 2 technology bgp and ldp signalled.
I will put my bet on A and C.
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Correct option are C and D.
draft-kompella-l2vpn-l2vpn —> BGP Layer 2 VPN
RFC 4447 ———————> LDP Layer 2 Circuit *1
RFC 4761 ———————> BGP VPLS
RFC 4762 ———————> LDP VPLS
All use martini encapsulation(RFC 4448) as data plane(control word).
*1 – draft-martini-l2circuit-encap-mpls already expired
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