Table of Contents
Advertisement
Unit Timing
The MX2800 STS-1 multiplexer allows three timing methods. The
first is
the incoming STS-1 signal. A failure in this signal, such as a loss-
of-signal (LOS) or a loss-of-framing (LOF) will cause the unit to
enter
defect. During
rate as the receive signal prior to entering its defect condition.
Stability of the transmit during
over 24 hours. The defect condition must be cleared before
time mode can be resumed.
The second mode of operation is
mode, an internal oscillator is used to generate transmit timing.
F
REE
specification of +/- 20 ppm.
The third timing operation mode is
mode allows the MX2800 STS-1 to derive its transmit timing from
any one of the 28 DSX-1/E1 physical ports. The ports selected may
be data carrying ports. Two sources can be specified to provide
external timing: a primary and a secondary source. Failure of the
primary source (due to LOS or AIS) will cause the unit to switch to
the secondary source, if available. In the event that both the primary
and secondary sources are lost, the unit will enter
as described previously. Holdover mode will be exited upon
recovery of at least one clock source.
SNMP
The MX2800 STS-1's embedded SNMP feature allows the unit to
be accessed and controlled by a network manager through the
10BaseT local area network (LAN) port. The MX2800 STS-1
61200659L1-1
timed, in which the multiplexer derives timing from
L
OOP
mode for the duration of the receive signal
H
(HO)
OLDOVER
HO
, the unit will continue transmitting at the same
-
mode provides a SONET minimum clock
RUNNING
MX2800 STS-1 User Manual
Chapter 1. Introduction
is guaranteed to +/- 4.9 ppm
HO
F
-R
(FR)
REE
UNNING
E
.
E
XTERNAL
XTERNAL
H
L
OOP
mode. In this
timing
mode
OLDOVER
1-5
Advertisement
Table of Contents
