Information for opnet modeler users, Model architecture – IBM 6 MPLS User Manual
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Specialized Models User Guide
6
MPLS Model User Guide
SPM-6-22
Modeler/Release 10.0
Information for OPNET Modeler Users
The rest of this document contains information for model developers (such as 
OPNET Modeler users). The following sections describe the topics necessary 
for understanding the internal details of and interfacing to the MPLS model.
Model Architecture
Each node that can use MPLS has an IP module, which contains a dispatcher 
process that spawns MPLS processes. The following table lists the process 
models used by the MPLS model.
Table 6-4 MPLS Process Models
Process model
Description
mpls_mgr
One instance of this process is spawned by ip_dispatch on 
each MPLS enabled node in the network. It represents the 
forwarding component of MPLS and the forwarding control 
plane. 
When the IP module of an LSR receives labeled packets or 
packets with matching FEC descriptions, it performs no IP 
processing on the packet. Instead, the packet is re-directed to 
the mpls_mgr process for MPLS forwarding. 
mpls_mgr uses ILM (incoming label map) and FTN (FEC to 
NHLFE maps) to forward packets.
mpls_ldp_mgr
Implements the LDP control plane in the LDP module of all 
routers. This process is the dispatcher for the 
mpls_discovery_mgr, mpls_session_mgr, and mpls_lsp_mgr 
processes. 
mpls_discovery_mgr
Sends periodic broadcast hello messages over UDP to 
discover MPLS-enabled neighbor routers. 
mpls_session_mgr
Negotiates, opens, and maintains TCP sessions to neighboring 
LDP routers. The TCP sessions are used to exchange label 
maps. This process is based on RFC 3036.
mpls_lsp_mgr
Controls the exchange-to-label mappings between LDP peers. 
Communication with LDP peers occurs through the session 
established by the mpls_session_mgr process. This process is 
based on RFC 3036.
End of Table 6-4
