Ericsson MINI-LINK TN R4 ETSI - Page 57

Basic Node
The 1+1 E1 SNCP function is independent of the 1+1 radio protection and
the MSP 1+1.
6632
Tx
Rx
Tx
Rx
Protected E1
Unprotected E1Unprotected E1
Protected E1
1+1 E1 SNCP group
1+1 E1 SNCP group
Link or
sub-network
Figure 42 1+1 E1 SNCP principle
Performance data is collected and fault management is provided for unprotected
as well as protected VC interfaces (that is the 1+1 E1 SNCP group). This gives
accurate information on the availability of network connections.
3.10.2.2 1+1 SDH SNCP
1+1 SDH Sub-Network Connection Protection (1+1 SDHSNCP) is a protection
mechanism used for network protection on VC4, VC3 or VC12 level, between
two MINI-LINK TN R4 NEs. It is based on the simple principle that one VC4,
VC3 or VC12 is transmitted on two separate VC4, VC3 or VC12 connections
(permanently bridged).
The switching is performed at the receiving end where the two connections are
terminated. It switches automatically between the two incoming VC4, VC3 or
VC12s in order to use the better of the two. The decision to switch is based on
signal failure of the signal received (LOP or AIS).
At each end of the protected VC4, VC3 or VC12 connection, two VC4, VC3 or
VC12 level connections must be configured to form a SNCP group.
An operator may also control the switch manually.
The connections may pass through other equipment in between, provided
that AIS is propagated end-to-end.
The 1+1 VC SNCP function is independent of the 1+1 radio protection and
the MSP 1+1.
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