IBM3009K2672
IBM SONET/SDH Framer
1:4 Protection with One SONET/SDH Framer: Normal Operation
APH
APH
APH
APH
APH
APH
APH
APH
TACC
RACC
To/From
To/From
External TX
External RX
APS
APS
Protection
Channel
Protection
Channel
Working Channels
Working Channels
1:4 Protection with One SONET/SDH Framer: Switch and Bridge to Protection Channel
APH
APH
APH
APH
APH
APH
APH
APH
TACC
RACC
To/From
External TX
APS
To/From
External RX
APS
Protection
Channel
Protection
Channel
Working Channels
Working Channels
As shown in the previous figures, the External Transmit and Receive APS interfaces do not need to be used
for the 1:4 protection scheme. However, if multiple SONET/SDH framers are used, then the External Transmit
APS interfaces of the SONET/SDH framers can be connected together and, similarly, the External Receive
APS interfaces of the SONET/SDH framers can be connected together. In this way a 1:N protection scheme
can be achieved. N can range from 1-14 depending on the number of SONET/SDH framers used. The next
two figures show a 1:N APS scheme when there is no failure and when there is a failure.
The APS functionality is not active when STM-4c or STS-12C payloads are being processed or when the
Telecom Bus interface is being used. Only when ATM and PPP data in 4 x STM-1/STS-3c are processed can
the TACC and RACC be used, since the external APS port can handle data from only one STM-1/STS-3c
stream at a time. However, the TACC/RACC are still operational in STM-4 and STS-12 modes, but only one
C-4 can be switched/bridged.
Block Diagram and Block Descriptions
Page 10 of 279
ssframer.01
8/27/99
IBM [ IBM ]
