Marconi OMS 1200
Technical Product Description
221 02-ZAP 701 25/1 Rev C 2006-08-04
© Ericsson AB 2006
03PHB00004AAV-CUA
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7.11.6
Multi Ring Switch
This parameter allows the operator to Enable/Disable Multiple Ring Switch handling in
the Ring. This permits the MS-Spring managers to either operate on Ring Bridge
requests, when multiple Ring Bridge requests become active on the Ring (refer to
Figure 7-12) or to clear down multiple requests to No Request conditions. In this latter
case, clearing down will leave unprotected failures in the Ring. The MS-Spring
Manager will raise the new protection switch status event - ‘No Request’. However it
shall also raise a ‘Multiple Multiplex Section Fail’ supervisory alarm.
The default config is ‘Multiple Ring Switch Handling - Disabled’.
The configuration must be applied to all NEs in the Ring, in common.
When Multiple Ring Switches are disabled no traffic misconnections can occur in the
MS-Spring.
If the operator ‘Enables’ Multiple Ring Switches, they must be warned that multiple
Ring Switch actions can cause traffic misconnections in the MS-Spring (refer to Figure
7-13), unless they set up Trail Trace processing at the VC- layer (and/or Tandem VC-
layer) trail termination points across the Network and enable fault actions AIS injection
from defect detections.
Where an MS-Spring Manager actions a Ring Switch request, when another Ring
Switch is active on the Ring, it shall raise a ‘Potential Network Traffic Misconnections’
supervisory alarm. In this way, when VC- / Tandem VC- trail trace mismatch alarms
are detected in the Network due to actual misconnections, there is an indication of the
potential cause from the MS-Spring switching Nodes.
7.11.7
Path of TCM Trail Trace used for Squelch of Mis–Connected Traffic
With multiple Ring Switch handling by NEs in a Ring network, there is the potential for
traffic misconnections. That is, where more than one NE bridges worker traffic onto
the Ring protection channels, then the different worker signals could each contend for
access to the same protection channels in certain spans of the Ring.
To prevent misconnections the Network relies on VC– (and Tandem VC–) Trail Trace
processing at the path termination points. Trail Trace Mismatch (dTIM) invokes signal
squelching with AIS injection.
7.11.8
Signal Squelching Rules
The following basic rules apply for squelching signal misconnections caused by
multiple Ring Switch request handling in MS–SPRINGs.
•
If MS–SPRINGs are set up in a single operator Network, VC–1/2/3/4 layer
signal squelching will be applied at the Nodes which handle the VC– trail
termination points, from VC– Trail Trace Mismatch detection, for all VC–s
which traverse an MS–SPRING.
•
If MS–SPRINGs are set up in an operator’s Domain in a multi–operator
Network, and that Domain predominantly uses Nodes with FULL TCM
functionality, VC–1/2/3/4 layer signal squelching will be applied as identified
above. For any Tandem VC–s which traverse an MS–SPRING, signal
squelching will be applied at the Tandem VC– trail termination points, from
Tandem VC– Trail Trace Mismatch detection. This may be handled both by
TCM Boundary Nodes, and by Tandem trail termination Nodes.
