In an environment that is using LDP signaling to establish LSPs, the MPLS Topology Server matches various attributes (LocalAddress, PeerAddress) that are associated with the LdpProtocolEndpoints that are discovered on different PE and P devices, and creates an LdpAdjacency instance for each complementary match. the MPLS Topology Server sets each instance’s isTargeted attribute to False, to indicates that this LDP session is not targeted.
An LdpAdjacency is ConnectedTo two LdpProtocolEndpoints, where one LdpProtocolEndpoint is HostedBy one PE or P device, and the second is HostedBy a peering PE or P device. The LdpAdjacency provides a bidirectional signaling path through which the two directly connected peering devices exchange MPLS label information for the purpose of constructing, maintaining, or deleting LDP LSPs.
Here are some other relationships that are computed for LdpAdjacency (non-targeted):
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.
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.
LdpAdjacency relationship Underlying
Points from an LdpAdjacency to the LDP LSP that is associated with the LdpAdjacency.