Cisco ASR 900 Series Configuration Guide

Overview of SDH
SDH was defined by European Telecommunications Standards Institute (ETSI) and is now being controlled
by the ITU-T standards body. SDH standard is prevalently used everywhere outside North America and Japan.
The following are true for SDH:
•
Network Node Interface (NNI) defined by CCITT/ITU-TS for worldwide use and partly aompatible
with SONET
•
One of the two options for the User-Network Interface (UNI) (the customer connection) and formally
the U reference point interface for support of BISDN
Basic SDH Signal
The basic format of an SDH signal allows it to carry many different services in its VC because SDH signal
is bandwidth-flexible. This capability allows the transmission of high-speed packet-switched services, ATM,
contribution video, and distribution video. However, SDH still permits transport and networking at the 2
Mbit/s, 34 Mbit/s, and 140 Mbit/s levels, accommodating the existing digital hierarchy signals. In addition,
SDH supports the transport of signals based on the 1.5 Mbit/s hierarchy.
SDH Hierarchy
SDH Frame Structure
The STM-1 frame is the basic transmission format for SDH. The frame lasts for 125 microseconds, therefore,
there are 8000 frames per second. The STM-1 frame consists of overhead plus a Virtual Container (VC)
capacity.
1-Port OC-192 or 8-Port Low Rate CEM Interface Module Configuration Guide, Cisco IOS XE Everest 16.7.x
(Cisco ASR 900 Series)
70
Configuring SDH on 1-Port OC-192/STM-64 or 8-Port OC-3/12/48/STM-1/-4/-16 Module
Overview of SDH

Cisco ASR 900 Series Specifications

General

Brand	Cisco
Model	ASR 900 Series
Category	Network Router
Language	English