Ldp Session Establishment And Maintenance; Figure 14 Ldp Session Establishment - Zte ZXR10 8900 Series User Manual

F 14 LDP S
IGURE ESSION
LDP Session Establishment and
Maintenance
ZXR10 supports LDP regulations defined in RFC3036, including
neighbor discovery, label request, label mapping, label repeal, la-
bel release and error management.
� Neighbor discovery: LSR sends Hello messages to neighbors
periodically to discover LDP peers.
� Session establishment and maintenance: LSRs establish TCP
connections and finish session initializations.
� LSP establishment and maintenance: LSRs distribute labels for
FECs and establish LSPs.
� Session repeal: when session hold time ends, the session is
interrupted.
The detailed procedure of LDP session establishment is described
as follows, as shown in
E
STABLISHMENT
1. R1 and R2 send multicast Hello messages to protocol inter-
faces. The messages are encapsulated by UDP and port num-
ber is 646. Meanwhile, protocol interfaces on R1 and R2 mon-
itor Hello messages in real time to discover neighbors.
2. After R1 and R2 receive Hello messages, they judge whether
the session is established with the peer. If session has not
been established, they prepare to establish a session. The
session is a TCP connection establishment procedure, using
port number 646. Before establishing the TCP connection, R1
Confidential and Proprietary Information of ZTE CORPORATION
Chapter 2 MPLS Configuration
Figure 14.
17