7-23
Cisco ONS 15454 Installation and Operations Guide
November 2001
Chapter7 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 a nd i nsert s STM tra ffic in
unprotected or 1+1 protection mode. Each STM-1 signal is mapped as a 155 Mbps co ncat ena ted sign al
(STS-3c) for transparent transport over a SONET network. The or igin al ST M- 1 tr affic ma y be ha nded
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 per forms se c tion a nd line o ve rhea d
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 rema pp ed i nto a n STM -1 fo r han doff
to an SDH network element (node). Tab le 7-9 shows the SDH ov er 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 s igna ls .
•The path overhead (POH) must be compatible on both sides an d 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 (p ay lo ad f orm at ) .
•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, ch oose SDH .
Step 4 Click Apply.
Tab l e 7-9 OC - N – SDH Over SONET Mapping
Card SDH SDH over SONE T
OC-3 STM-1 STS-3c
OC-12 STM-4 STS-12c
OC-48 STM-16 STS-48c
OC-192 STM-64 STS-192c