To convert from PDH to SDH, I use something called container, and this is fixed size, because SDH is Synchronous and PDH is Plesiochronous.
- C-12 >> container (9*4)-2= 34 Byte.
- LO-POH >> Lower order path overhead (for VC-11, VC-12 or VC-2).
- VC-12 >> Virtual Container-12 (C-12 + LO-POH ).
- TU-PTR >> Tributary unit pointer (1-3 Level).
- TUG-2 >> Tributary User Group 2.
- TUG-3 >> Tributary User Group 3.
- C-4 >> Level 4.
- AU-PTR >> Administrative Unit pointer (Level 4).
- RSOH >> Regenerator section overhead.
- MSOH >> Multiplex section overhead.
63 E1= 3 TU-12 * 7 TUG-2 * TUG-3 = 63 E1 or 3 E3 or 1 E4
STM Hierarchy and Container Bit Rates.
- STM-1: 155,520 kbit/s. (155 Mbit/s)
- STM-4: 622,080 kbit/s. (620 Mbit/s)
- STM-16: 2,488,320 kbit/s. (2.5 Gbit/s)
- STM-64: 9,953,280 kbit/s. (10 Gbit/s)
SDH allows for various PDH input rates to be mapped into containers as shown below:
- Container C11: 1544 kbit/s (1.5 Mbit/s)
- Container C12: 2048 kbit/s (2 Mbit/s)
- Container C2: 6312 kbit/s (6 Mbit/s)
- Container C3: 49,536 kbit/s (45 & 34 Mbit/s)
- Container C4: 139,264 kbit/s (140 Mbit/s)
- RSOH, MSOH, LO-POH, HO-POH: will be explained later.
Credits: 