Cisco ONS 15327, Пользовательская документация

Страница: 140 / 559

3-14
Cisco ONS 15327 User Documentation, R3.3
June 2002
Chapter 3 Node Setup
Setting Up ONS 15327 Timing
Step 3
In the BITS Facilities section, complete the following information:
Note
The BITS Facilities section sets the parameters for your BITS1 and BITS2 timing references.
Many of these settings are determined by the timing source manufacturer. If equipment is
timed through BITS Out, you can set timing parameters to meet the requirements of the
equipment.
•
State —Set the BITS reference to IS (In Service) or OOS (Out of Service). For nodes set to Line
timing with no equipment timed through BITS Out, set State to OOS. For nodes using External
timing or Line timing with equipment timed through BITS Out, set State to IS.
•
Coding —Set to the coding used by your BITS reference, either B8ZS or AMI.
•
Framing —Set to the framing used by your BITS reference, either ESF (Extended Super Frame, or
SF (D4) (Super Frame). SSM is not available with Super Frame.
• Sync Messaging —Check to enable SSM.
•
AIS Threshold— Sets the quality level where a node sends an Alarm Indication Signal (AIS) from
the BITS 1 Out and BITS 2 Out MIC connections. When a node times at or below the AIS Threshold
quality, AIS is sent (used when SSM is disabled or frame is SF).
• LBO— Line build out (LBO) relates to the length of the bits cable. Select the appropriate distance
depending on the length of cable required to connect the ONS 15327 BITS port to the BITS timing
source.
Step 4
Under Reference Lists, complete the following information:
Note
Reference lists define up to three timing references for the node and up to six BITS Out
references. BITS Out references define the timing references used by equipment that can be
attached to the node’s BITS Out connections on the MIC. If you attach equipment to BITS
Out connections, you normally attach it to a node with Line mode because equipment near
the External timing reference can be directly wired to the reference.
•
NE Reference —Allows you to define three timing references (Ref 1, Ref 2, Ref3). The node uses
Reference 1 unless a failure occurs to that reference, in which case, the node uses Reference 2. If
that fails, the node uses Reference 3, which is typically set to Internal Clock. This is the Stratum 3
clock provided on the XTC. The options displayed depend on the Timing Mode setting.
– Timing Mode set to External—options are BITS1, BITS2, and Internal Clock.
–
Timing Mode set to Line—options are the node’s working optical cards and Internal Clock.
Select the cards/ports that are directly or indirectly connected to the node wired to the BITS
source, that is, the node’s trunk cards. Set Reference 1 to the trunk card that is closest to the
BITS source. For example, if Slot 5 is connected to the node wired to the BITS source, select
Slot 5 as Reference 1.
– Timing Mode set to Mixed—both BITS and optical cards are available, allowing you to set a
mixture of external BITS and optical trunk cards as timing references.
•
BITS 1 Out/BITS 2 Out —Define the timing references for equipment wired to the BITS Out
connections on the MIC. Normally, BITS Out is used with Line nodes, so the options displayed are
the working optical cards. BITS 1 and BITS 2 Out are enabled as soon as BITS-1 and BITS-2
facilities are placed in service.