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Cisco ONS 15454 Installation and Operations Guide
November 2001
Chapter 7 Card Provisioning
Provisioning Optical Cards
Click Apply.
7.3.2 Provisioning OC-N Cards for SDH
You can provision the ONS 15454 OC-3, OC-12, and OC-48 cards to support either SONET or SDH over
SONET signals. When provisioned for SDH, each OC-N port drops and inserts STM traffic in
unprotected or 1+1 protection mode. Each STM-1 signal is mapped as a 155 Mbps concatenated signal
(STS-3c) for transparent transport over a SONET network. The original STM-1 traffic may be handed
off as an STM-1 or OC-3.
Because SDH and SONET frame format and size are nearly identical, their line speeds meet, starting at
155 Mbps. For example, at the STM-1/OC-3 level, the ONS 15454 performs section and line overhead
conversions and maps the 261x9 byte VC-4 into an STS-3c for transparent transport across the SONET
domain. At the far end, the STS-3c carrying the original VC-4 is remapped into an STM-1 for handoff
to an SDH network element (node). Table 7-9 shows the SDH over SONET mapping for the ONS 15454
OC-N cards.
The ONS 15454 performs section, line overhead, and pointer conversions between SDH and SONET.
However, to ensure operability, the following requirements must be met:
• The embedded payload must be compatible on both sides and require no conversion of any kind.
Examples of such payloads include concatenated ATM or Packet over SONET/SDH signals.
• The path overhead (POH) must be compatible on both sides and require no conversion of any kind.
Each overhead byte must be processed identically or simultaneously ignored. Key POH bytes to
consider are the J1 (path indicator) and C2 (payload format).
• You cannot enable intermediate path protection monitoring (IPPM) on OC-12 and OC-48 ports that
are enabled for SDH.
Most SONET and SDH routers and ATM switches can be configured to meet these requirements.
Procedure: Provision an OC-N Card for SDH
Step 1 Log into the node and double-click the OC-N card.
Step 2 Click the Provisioning > Line tabs.
Step 3 Under Type, choose SDH.
Step 4 Click Apply.
Ta b l e 7 - 9 O C - N – SDH Over SONET Mapping
Card SDH SDH over SONET
OC-3 STM-1 STS-3c
OC-12 STM-4 STS-12c
OC-48 STM-16 STS-48c
OC-192 STM-64 STS-192c