In an environment that is using LDP signaling to establish L2VPNs, the MPLS Topology Server matches various attributes (LocalAddress, PeerAddress) that are associated with the LdpProtocolEndpoints that are discovered on different PE devices, and creates an LdpAdjacency instance for each complementary match. The MPLS Topology Server sets each instance’s isTargeted attribute to True, to indicates that the LDP session is targeted.
An LdpAdjacency is ConnectedTo two LdpProtocolEndpoints, where one LdpProtocolEndpoint is HostedBy one PE device, and the second is HostedBy another PE device. The LdpAdjacency provides a bidirectional signaling path through which the two PE devices exchange VC ID and other types of information for the purpose of constructing, advertising, maintaining, or deleting PseudoWires between the two PE devices.
Here are some other relationships that are computed for LdpAdjacency (targeted):
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LdpAdjacency relationship Endpoint1
Points from an LdpAdjacency to the LdpProtocolEndpoint that has the lower IP address of the two endpoints that are associated with the LdpAdjacency.
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LdpAdjacency relationship Endpoint2
Points from an LdpAdjacency to the LdpProtocolEndpoint that has the higher IP address of the two endpoints that are associated with the LdpAdjacency.
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LdpAdjacency relationship Underlying
Points from an LdpAdjacency to the one or more PseudoWires that are associated with the LdpAdjacency.