Multi-Tech Systems FR111 - Manual (Page 63)

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LMI describes a protocol and associated procedures operating on the local
interface between the user and the network. It notifies the user of the
addition, deletion, and presence of the PVC in the network. It also notifies
the user of the end-to-end availability or unavailability of a PVC. Basic LMI
protocol is based on a synchronous polling scheme where the user polls
the network to obtain status information on the PVCs configured on the
interface. LMI simply augments the ANSI/CCITT standard Frame Relay
protocol and in no way interferes with the normal operation of user PVCs
on the interface.
Annex D provides additional procedures for permanent virtual connections
using unnumbered information frames. Annex D describes the means for
notification of outage of a permanent virtual connection and recovery from
such a condition. This follows the ANSI T1.617 standards.
Annex A provides additional procedures for permanent virtual connections
using unnumbered information frames. Annex A describes the means for
notification of outage of a permanent virtual connection and recovery from
such a condition. This follows the ITU-T Q.933 standard
Encapsulation Type
The Encapsulation Type depends on the type of device that is connected
at the other end of the trunk. If another MultiFRAD 100 is connected at the
other end of the trunk, then the Mux mode is used. If a non-MultiFRAD 100
is at the other end of the trunk, then the Raw mode is used.
Management Parameters
Polling Interval
The Polling Interval defines a time period in which a status enquiry message
is sent from the MultiFRAD to the network. The Status Enquiry message
requests the status of the PVC(s) or verification of the status of a physical
link. When the Status Enquiry message is sent by the MultiFRAD, the Polling
Interval is restarted. The network responds with a status message that
reports the status of the PVC or verifies the integrity of the physical link. The
polling interval is 5 to 30 seconds with a default of 10 seconds.