Enhanced Fec (E-Fec) Feature - Cisco ONS 15454 DWDM Reference Manual

8.4.5 Enhanced FEC (E-FEC) Feature

and regenerate) transponder functionality for this 10-Gbps trunk interface. Therefore, the card is suited
for use in long-range amplified systems. The DWDM interface is complaint with ITU-T G.707, ITU-T
G.709, and Telcordia GR-253-CORE standards.
The DWDM trunk port operates at a rate that is dependent on the input signal and the presence or absence
of the ITU-T G.709 Digital Wrapper/FEC. The possible trunk rates are:
•
•
•
•
The maximum system reach in filterless applications without the use of optical amplification or
regenerators is nominally rated at 23 dB over C-SMF fiber. This rating is not a product specification, but
is given for informational purposes. It is subject to change.
8.4.5 Enhanced FEC (E-FEC) Feature
A key feature of the TXP_MR_10E is the availability to configure the forward error correction in three
modes: NO FEC, FEC, and E-FEC. The output bit rate is always 10.7092 Gbps as defined in
ITU-T G.709, but the error coding performance can be provisioned as follows:
•
•
•
The E-FEC of the ONS 15454 and Cisco ASR 9000 are not compatible.
Note
8.4.6 FEC and E-FEC Modes
As client side traffic passes through the TXP_MR_10E card, it can be digitally wrapped using FEC
mode, E-FEC mode, or no error correction at all. The FEC mode setting provides a lower level of error
detection and correction than the E-FEC mode setting of the card. As a result, using E-FEC mode allows
higher sensitivity (lower optical signal-to-noise ratio [OSNR]) with a lower bit error rate than FEC
mode. E-FEC enables longer distance trunk-side transmission than with FEC.
The E-FEC feature is one of three basic modes of FEC operation. FEC can be turned off, FEC can be
turned on, or E-FEC can be turned on to provide greater range and lower BER. The default mode is FEC
on and E-FEC off. E-FEC is provisioned using CTC.
Because the transponder has no visibility into the data payload and detect circuits, the TXP_MR_10E
Caution
card does not display circuits under the card view.
8.4.7 Client-to-Trunk Mapping
The TXP_MR_10E card can perform ODU2-to-OCh mapping, which allows operators to provision data
payloads in a standard way across 10-Gbps optical links.
Cisco ONS 15454 DWDM Reference Manual, R8.5
8-14
OC192 (9.95328 Gbps)
OTU2 (10.70923 Gbps)
10GE (10.3125 Gbps) or 10GE into OTU2 (ITU G.sup43 11.0957 Gbps)
10G FC (10.51875 Gbps) or 10G FC into OTU2 (nonstandard 11.31764 Gbps)
NO FEC—No forward error correction
FEC—Standard ITU-T G.975 Reed-Solomon algorithm
E-FEC—Standard ITU-T G.975.1 I.7 algorithm, which is a super FEC code
Chapter 8 Transponder and Muxponder Cards
78-18343-02