This section contains information on the following topics:
The 7705 SAR supports SONET/SDH ports on the following adapter cards:
4-port OC3/STM1 Clear Channel Adapter card
2-port OC3/STM1 Channelized Adapter card
4-port OC3/STM1 / 1-port OC12/STM4 Adapter card
SONET/SDH ports can be clear channel (non-channelized) and channelized. The 4-port OC3/STM1 Clear Channel Adapter card supports only clear channel ports. The 2-port OC3/STM1 Channelized Adapter card supports channelized ports. The 4-port OC3/STM1 / 1-port OC12/STM4 Adapter card is a mixed-use adapter card that supports clear channel and channelized ports. The mda-mode command is used to configure the 4-port OC3/STM1 / 1-port OC12/STM4 Adapter card for 4-port or 1-port mode. See Configuring Cards for details.
Clear channel ports use the whole port—other than overhead bytes—as a single stream of bits. Channelized ports use various channel hierarchies to split the larger bandwidth into smaller channels, such as DS1, E1, DS3, or E3. Figure: SONET Hierarchy at STS-12 and Figure: SDH Hierarchy at STM-4 show the standards-based channel mapping for SONET and SDH, respectively. Channelized ports on the 2-port OC3/STM1 Channelized Adapter card and the 4-port OC3/STM1 / 1-port OC12/STM4 Adapter card support a subset of the standards-based mapping options, as shown in Table: SONET/SDH Paths Supported on the 7705 SAR .
For SONET, the basic frame format unit is STS-1 (51.84 Mb/s), which is carried in the optical carrier level 1 (OC-1) signal, and three STS-1 frames can be carried in an STS-3 frame at the OC-3 level. For SDH, the basic frame format unit is STM-1 (155.52 Mb/s), which is carried in an OC-3 signal. SDH STM-1 using OC-3 and SONET STS-3 are functionally equivalent.