An LDP Layer 2 circuit is configured for VPN A and VPN B.Which three statements are true regarding LDP Layer 2 circuit signaling? (Choose three.)
A.
PE-P LDP sessions use Martini encapsulation.
B.
PE-PE LDP sessions can be extended or adjacent.
C.
VRF tables are needed on the PEs.
D.
TCC encapsulation is needed to interconnect different interface types.
E.
The VC type field in the LDP header specifies the encapsulation type.
The Junos operating system offers support for Layer 2 circuits based on the signaling techniques
defined in RFC 4447. Only remote provider edge (PE)-to-PE connections are supported; you cannot
use the LDP Layer 2 circuits to establish connections between customer edge (CE) devices that
attach to the same PE router.
LDP Signaling
RFC 4447 specifies the use of LDP for exchanging virtual circuit (VC) labels between PE routers. As a
result, PE routers no longer require BGP signaling between them. LDP Layer 2 circuits based on RFC
4447 do not use site identifiers, route distinguishers, or VPN routing and forwarding (VRF) policy.
RFC 4447 makes use of LDP extended neighbor relationships (as is used for LDP-over-RSVP tunnels)
such that the PE routers establish extended LDP sessions as needed, despite their not being directly
connected neighbors.If wanted, the LDP session between PE routers can be tunneled over a traffic
engineered RSVP path.
CCC or TCC Encapsulation
Configuring a LDP Layer 2 circuit is very similar to configuring CCC or translational cross-connect
(TCC) connections. When CCC encapsulation is used, the Layer 2 technology must be the same at
both ends of the connection. RFC 4447 connections are referred to as l2circuits in the Junos
OS.
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