Mdl Standards; Timeout Of Received Mdl Messages; Table 5: Mdl Message Strings And Message Types - Juniper PHYSICAL LAYER - CONFIGURATION GUIDE V11.1.X Configuration Manual

JUNOSe 11.1.x Physical Layer Configuration Guide

MDL Standards

You can configure T3 interfaces to send MDL messages that comply with ANSI
T1.107a-1990 Standard for Telecommunications Digital Hierarchy – Supplement
to Formats Specification (August 1990). MDL messages identify a particular link by
sharing common codes for data such as the equipment identifier, line identifier,
frame identifier, and unit.

Timeout of Received MDL Messages

When a line module receives an MDL message string, it stores the strings for a period
of 10 seconds after the last message was received. If the line module does not receive
another message of any type containing the same string within 10 seconds, it erases
the local copy of the message.
Most MDL message strings are common to all three types of messages that can be
transmitted: path identifications, idle signals, and test signals. Certain message strings,
however, are unique to a particular message type. Table 5 on page 46 briefly describes
each MDL message string and indicates, with a checkmark ( ), the types of messages
in which it can be sent.

Table 5: MDL Message Strings and Message Types

As long as another message of any type containing the same string is received within
10 seconds, the line module retains the local copy of the message string and resets
the 10-second timer for that string.
For example, if a line module receives an MDL test signal message containing an eic
string, and then receives a idle signal message within 10 seconds that also contains
an eic string, it retains the local copy of the most recent eic string received and resets
the 10-second timer for that message. However, if 10 seconds pass without the line
module receiving a path identification, test signal, or idle signal message containing
an eic string, the line module erases the local copy of the eic message string.
46
Overview
Message
String Description
eic Equipment identification code
fic Frame identification code
generator Generator number
lic Line identification code
pfi Facility identification code
port Equipment port number
unit Unit identification code
Path Idle Signal Test Signal
Message Message Message
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