Nortel Networks 8000 - Manual (Page 295)

Nortel Secure Router 8000 Series
Configuration -WAN Access 8 Frame relay configuration
You need to manually maintain static mapping. Its security and reliability is higher than
the dynamic FR address mapping.
FR LMI protocol
The LMI protocol maintains the link and PVC status of the FR through the status enquiry
packet and the status packet.
The maintenance consists of:
• Adding the PVC record
• Deleting the interrupted PVC record
• Monitoring the change of PVC status
• Authenticating the link integrity
The system supports three LMI protocols:
• LMI complying with ITU-T Q.933 Appendix A
• LMI complying with ANSI T1.617 Appendix D
• Nonstandard compatible protocol
Their working mechanism is as follows:
• DTE sets a status enquiry packet at certain intervals to search the VC status.
• After receiving the packet, the destination DTE notifies the status of all the VCs to the
interfaces through the status packet.
Meanings of the parameters used in the above process are shown in Table 8-1. You can
configure the parameters to optimize the functioning of the device.
Table 8-1 Meanings of FR LMI protocol parameters
Operation
Mode
Parameter Range Default
Value
DTE The PVC status request timer
(N391) 1 to 255 times 6 times
Error threshold (N392) 1 to 10 times 3 times
Event timer (N393) 1 to 10 times 4 times
Polling timer on DTE (T391),
with 0 indicating that LMI
protocol is prohibited.
5 to 30 seconds 10 seconds
DCE Error threshold (N392) 1 to 10 times 3 times
Event timer (N393) 1 to 10 times 4 times
Polling timer on DCE (T392) 5 to 30 seconds 15 seconds
These parameters are defined in the Q.933 Appendix A as follows:
The meanings of the parameters related to DTE are as follows:
Issue 5.3 (30 March 2009) Nortel Networks Inc. 8-5