Chapter 5 Viewing MPLS Logical Inventory
Viewing MPLS VPN Properties
Two LDP peer discovery types are supported:
•Basic discovery—Used to discover directly connected LDP LSRs. An LSR sends hello messages to the all-routers-on-this-subnet multicast address, on interfaces for which LDP has been configured.
•Extended discovery—Used between indirectly connected LDP LSRs. An LSR sends targeted hello messages to specific IP addresses. Targeted sessions are configured because the routers are not physically connected, and broadcasting would not reach the peers. The IP addresses of both peers are required for extended discovery.
Note If two LSRs are connected with two separate interfaces, two LDP discoveries are performed.
The following properties are displayed on the LDP Neighbors tab for each LDP peer:
•LDP ID—The LDP identifier of the neighbor (peer) for the session.
•Transport IP Address—The IP address advertised by the peer in the hello message or the hello source address.
•Session State—The current state of the session, which may be one of the following:
–Transient
–Initialized
–Open Rec
–Open Sent
–Operational
•Protocol Type—The protocol used to establish the session, which may be LDP or TDP (Tag Distribution Protocol).
•Label Distribution Method—The method of label distribution. This might be Downstream or Downstream On Demand.
•Session Keepalive Interval—The negotiated number of seconds between keepalive messages.
•Session Hold Time—The amount of time (in seconds) that an LDP session can be maintained with an LDP peer, without receiving LDP traffic or an LDP keepalive message from the peer.
•Discovery Sources—An indication of whether the peer has one or more discovery sources.
Note You can see the discovery sources in the LDP Neighbor Properties window, by double-clicking the row of the peer in the table.
•Sending Alarms—This option is currently unavailable.
Double-clicking an entry (peer) in the table opens the LDP Neighbor Properties window that displays the basic and targeted discovery sources for the peer. Each peer can have several discovery sources. The following information is displayed:
•Interface Name—The interface on which LDP is configured.
•Source IP Address—The IP address of the peer that sends the targeted hello messages for extended discovery.
•Adjacency Type—The type of LDP adjacency used for discovery, which may be Link (basic) or Targeted (extended).
•Sending Alarms—This option is currently unavailable.
Cisco Active Network Abstraction 3.6.6 MPLS User Guide
