Ring Switch - Ericsson Marconi OMS 1200 Product Description

7.12.1

Ring Switch

There is only a single physical section around the Ring. Normal traffic connections are
set up on the allocated Worker channels (for example. channels #1–8). Protection
channels, which are normally idle (i.e. Protection channels #9–16), provide a shared
resource for channel protection switching.
Transmission Failure
When there is a complete failure of both Worker and Protection sections on the Span
between Nodes B and C, then a full Ring switch is required to restore the transport
circuit X traffic. Node B senses the failure and Bridges Working channels East-bound
onto Protection channels West-bound, away from the failure. Nodes F, E and D
provide pass-through connections for the protected traffic to complete a path to Node
C. In response to the Bridge at Node B, Node C Switches the protected traffic from
East back onto Worker channels East-bound. Node D now receives the working traffic
from West, as if no failure had occurred.
In the reverse direction of transmission, with Node C also detecting failure, it would
Bridge Working channels West-bound onto Protection channels East-bound, away
from the failure and Node B would Switch the protected traffic from West back onto
Worker channels West-bound. Node A then, is not aware of failure either.
Note:
Note:
221 02-ZAP 701 25/1 Rev C 2006-08-04
03PHB00004AAV-CUA
Transport circuit Y is unaffected by the protection switching. Likewise, circuit
connections between, Node B and Node A, or B and F via A, are not
affected by the protection switching.
As both Worker and Protection sections are transported on the same
physical medium, there are no Span Switch options in 2–Fibre Rings.
Marconi OMS 1200
Technical Product Description
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