User manual

Wide Bank 28 DS3 - Release 2.4 July 2004 2-19
Product Description
Controller and DS3 Redundancy
Electronics and Network Protection Mode
The highest level of protection, electronics and network protection, allows both the Controller cards
and the DS3 lines to be switched. This mode is available with two Controllers and two active DS3
lines. Switching must be enabled (arm on) and protection must be enabled (DS3 protect on).In this
mode, the primary Controller is connected to the primary DS3 line and the secondary Controller is
connected to the secondary DS3 line. The low-speed transmit streams are multiplexed, framed and
simultaneously broadcast on both the primary and secondary DS3 lines, thus transmitting the
identical payload to the far-end service and protection line. Also, each Controller is framed up to its
respective DS3 line and the controller-select signal determines which Controller has access to the
low-speed cards, and thus carries the service.
Figure 2-9 Electronics and Network Protection Mode of the Wide Bank 28 DS3
If the active Controller malfunctions, the DS3 line condition deteriorates, or a maintenance switch
is invoked (the switch command), a protection switch will occur. The Wide Bank will enable the
secondary DS3 path through the other Controller card. If revertive switching is enabled (revertive
ds3 on), there will be a five minute delay (beginning when the previously-active Controller’s error
rate equals zero). Then the Wide Bank will switch back to the previously-active Controller and DS3
line, provided that there is no longer a malfunction in that path during the five-minute delay. If
revertive switching is not enabled (revertive ds3 off), no switch-back will occur.
Active
(Primary)
M13 Mux
Controller
DS3OUT+
DS3IN+
28/21 LS
XMT Stream
28/21 LS
RCV Stream
Electronics & Netrwork
Protection Mode
Standby
(Secondary)
M13 Mux
Controller
DS3OUT+
DS3IN+
28/21 LS
RCV Stream
28/21 LS
XMT Stream
Controller
Select
Disable
Enable
xmt
rcv
Primary
DS3
xmt
rcv
Secondary
DS3