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Cisco ONS 15454 Reference Manual, R7.0
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Chapter 6 Storage Access Networking Cards
6.3 6.2.4 Link Recovery
Data port disabled if SONET/SDH transport is errored

6.2.4 Link Recovery

Link recovery has the following features:
Reduces the impact of SONET/SDH disruptions on attached Fibre Channel equipment
Speeds up the recovery of Inter-Switch Links (ISLs)
Allows monitoring of B2B credit depletion due to SONET outage and full recovery of the credits,
thus preventing the slow decay of bandwidth/throughput
Note Distance extension and link recovery cannot be enabled at the same time.
6.3 FC_MR-4 Card Application
The FC_MR-4 card reliably transports carrier-class, private-line Fibre Channel/FICON transport
service. Each FC_MR-4 card can support up to four 1-Gbps circuits or four 2-Gbps circuits. Four
1.0625-Gbps FC channels can be mapped into containers as small as STS-1 (subrate), with a minimum
of STS-18c/VC4-6v for full rate. Four 2.125-Gbps FC channels can be mapped into containers as small
as STS-1 (sub-rate), with a minimum of STS-36c/VC4-12v for full rate.
The FC_MR-4 card incorporates features optimized for carrier-class applications such as:
Carrier-class Fibre Channel/FICON
50 ms of switch time through SONET/SDH protection as specified in Telcordia GR-253-CORE
Note Protection switch traffic hit times of less than 60 ms are not guaranteed with differential delay in effect.
Hitless software upgrades
Note Hitless software upgrades are not possible with an activation from Software R5.0 to Software R6.0 or
higher in enhanced card mode. This is because the FPGA must be upgraded to support differential delay
in enhanced mode. Upgrades are still hitless with the line rate mode.
Remote Fibre Channel/FICON circuit bandwidth upgrades through integrated Cisco Transport
Controller (CTC)
Multiple management options through CTC, Cisco Transport Manager (CTM), TL1, and Simple
Network Management Protocol (SNMP)
Differential delay compensation of up to 122 ms for diversely routed VCAT circuits
The FC_MR-4 payloads can be transported over the following protection types:
Path Protection
BLSR
Unprotected
Protection channel access (PCA)