Patton electronics 3120, Справочное руководство администратора

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14 • Frame Relay Model 3120 RAS Administrators’ Reference Guide
182 DLMI Window
Signalling (frDlcmiState)
Inband signalling used to communicate link and PVC status between the User equipment and the Network
equipment. LMI is the generic term used to indicate Frame Relay signaling, however the three specific types of
signaling are:
• LMI Frame Relay Forum Implementation agreement. Uses DLCI = 1023 for management
• Annex D. ANSI T1.617 Uses DLCI = 0 for management
• Annex A. ITU Q.933 Uses DLCI = 0 for management
Data Link Protocol (frDlcmiAddress)
The layer 2 link protocol for Frame Relay is LAPF, otherwise referred to as Q.922. The factory default of
q922(4) will be the most common.
DLCI Length (frDlcmiAddressLen)
The DLCI identifies the virtual connection on the bearer channel for the Frame Relay Interface. The factory
setting of two-octets(2) represents 10-bit addressing. Your access server can support a maximum of 32 separate
PVCs or virtual channels per Frame Relay link.
Polling Interval (T391)( frDlcmiPollingInterval)
Each side of the Frame Relay interface, the Network side and the User side, communicate status. T391 is the
number of seconds between subsequent Status Enquiry messages. An Error Count is logged if no response
from the previous Status Enquiry message was received during the T391 interval. The default value is 10.
Full Enquiry Interval (N391)( frDlcmiFullEnquiryInterval)
Status Enquiry messages are of two different varieties: 1) Link Integrity Verification, which simply exchange
sequence numbers between peers and 2) Full Status messages, which is a request from the peer for the list of all
active/inactive PVCs. The default is 6.
Error Threshold (N392)( frDlcmiErrorThreshold)
N392 is the number of errors (T392 and T391 timeouts and sequence number errors) before action is taken.
Action consists of changing all the PVCs from active to inactive. N392 must be less than or equal to N393.
The default value is 3.
Monitored Events (N393)( frDlcmiMonitoredEvents)
Expected and unexpected events are counted up till the Event Count reaches N393, whereupon the Event
Count is cleared and the Error Threshold Count is cleared. Events consist of timer (T391 and T392) expira-
tions and received Status Enquiry messages. N393 must be greater or equal to N392. The default value is 4.
MultiCast Service (frDlcmiMulticast)
TBD.
Max Virtual Circuits (frDlcmiMaxSupportedVCs)
The maximum number of PVCs determines the amount of internal resources are allocated for the Frame Relay
system. The default value is 32.