Carrier Access Broadmore 1750 - Manual (Page 158)

7-44 Broadmore 1750 - Release 4.6
Configuration
Unstructured DS3 SAM
Table 7-2: Unstructured DS3 SAM Configuration Items
Item Options Comments
Port Name A descriptive field to identify the port
Port Mode On-line
Off-line This is a status field that can be toggled to online or offline. When the port is in
offline status, it is not available to make calls, and passive SVCs are refused.
Framing C-bit
M13
Unframed C-bit is a framing mode using DS2 stuff bits associated with M23 multiplexing
for other purposes such as Far End Alarm Control (FEAC) Channel. M13 is a
mode that maps 28 DS1s directly into the DS3. The DS1s do not exist
independently as is the case when M23 multiplexing is used. Unframed requires
a 44.736 Mbps input.
Clock Mode SRTS
Adaptive
Network
BITS
Loop NOTE: SRTS is a proprietary timing algorithm and may ONLY be
used with specific written prior permission from Carrier Access
Corporation. Additional license fees may apply.
SRTS-This method measures the Service Clock input frequency against a
network-wide ATM synchronization clock and sends the difference signals in the
AAL1 header to the destination Broadmore 1700 circuit emulation interface. The
different signals are then combined with the network-wide ATM synchronization
clock to re-create the input service clock. If more than one ATM clock
synchronization is present in the network, an alternate timing recovery method
must be selected. For this method to work, the ATM network must be
synchronized to a single network-wide clock source. User equipment should be
configured to internal clock.
Adaptive Timing –This technique maintains a pre-defined fill level in the Circuit
Emulation Re-assembly buffer to control the timing output to user equipment.
This method of timing recovery does not require a Synchronous ATM network
and is used in applications where network wide synchronization is not available.
(Synchronous) Network-This method of clock recovery derives timing from the
ATM Network and propagates it to the CE Service Interface. The ATM network
must be synchronized to a single source clock. User equipment should be
configured to recover timing from the Broadmore 1700 CE service interface.
(Synchronous) Loop-The Broadmore 1700 CE interface will derive clock from
the attached DS3 user equipment and transmit from the CE interface at that rate.
The user equipment should be configured for Internal timing if the Broadmore
1700 CE service interface is configured for Synchronous loop.
BITS- (Building Integrated Timing Supply)- distributes standard timing to
equipment within the central office. The Broadmore 1700 accepts BITS via either
NIM IOM. The fallback for the primary BITS clock is the other BITS clock. The
fallback for no BITS is the internal clock of the NIM.