Optical Data Rate Derivations - Cisco ONS 15454 DWDM Reference Manual

10.9 Optical Data Rate Derivations

Figure 10-24
SPAN SPAN
10.9 Optical Data Rate Derivations
This section discusses the derivation of several data rates commonly used in optical networking.
10.9.1 OC-192/STM-64 Data Rate (9.95328 Gbps)
The SONET OC-1 rate is 51.84 Mbps. This rate results from a standard SONET frame, which consists
of 9 rows of 90 columns of 8-bit bytes (810 bytes total). The transmission rate is 8000 frames per second
(125 microseconds per frame). This works out to 51.84 Mbps, as follows:
STM-64 is an SDH rate that is equivalent to the SONET OC-192 data rate.
10.9.2 10GE Data Rate (10.3125 Gbps)
10.3125 Gbps is the standard 10 Gbps Ethernet LAN rate. The reason the rate is higher than 10.000 Gbps
is due to the 64-bit to 66-bit data encoding. The result is 10 Gbps x 66/64 = 10.3125 Gbps. The reason
for 64-bit to 66-bit encoding is to ensure that there are adequate data transitions to ensure proper
operation of a clock and data recovery circuit at the far end. Additionally, the encoding assures a data
stream that is DC balanced.
10.9.3 10G FC Data Rate (10.51875 Gbps)
The Fibre Channel rate is based on the OC-192 rate of 9.95328 Gbps, with the addition of 64-bit to 66-bit
encoding and WAN Interconnect Sublayer (WIS) overhead bytes.
Cisco ONS 15454 DWDM Reference Manual, R8.5
10-34
System Tilt Compensation With an ROADM Node
= 25 dB = 25 dB SPAN SPAN
1 1
DCU
OPT-PRE
G > 21dB
OPT-PRE
Unregulated Tilt
(9) x (90 bytes/frame) x (8 bits/byte) x (8000 frames/sec) = 51.84 Mbps
OC-192 is 192 x 51.84 Mbps = 9953.28 Mbps = 9.95328 Gbps
2 2
32 WSS 32 WSS
Per-channel
Power Equalization
Chapter 10 Network Reference
SPAN SPAN SPAN SPAN
3 3
OPT-BST
Tilt Reference = 0
4 4
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