In this blogtorial we will go over the basics of LDP, discuss how LDP adjacencies are formed, and also take a look at LDP packets on the wire to gain better understanding of the inner workings of LDP.
LDP stands for Label Distribution Protocol and it is used by routers to share label information about prefixes. For more information regarding LDP check out RFC 5036. At a high glance, LDP first uses UDP hello messages to discover neighbors on the shared segment and then forms a TCP peering with the LDP neighbor to share the label to prefix mapping information. We will see this in detail (packet captures) later in this blogtorial.
Here is a simple topology to follow along.