Cisco NCS 4200 Series Configuration Manual page 8

Modes of SDH
Modes of SDH
A Synchronous Transport Module (STM) signal is the Synchronous Digital Hierarchy (SDH) equivalent of
the SONET STS. In this document, STM term refers to both path widths and optical line rates. The paths
within an STM signals are called administrative units (AUs).
An AU is the information structure that provides adaptation between the higher-order path layer and the
multiplex section layer. It consists of an information payload (the higher-order VC) and an AU pointer, which
indicates the offset of the payload frame start relative to the multiplex section frame start.
The AU-3 pointer is composed of 3 bytes; the AU-4 pointer is composed of 9 bytes.
The payload of the STM-1 frame consists of one AU-4 unit or three AU-3 units.
Augment Mapping
An administrative unit group (AUG) consists of one or more administrative units occupying fixed, defined
positions in an STM payload. Augment mapping is supported at STM1 level.The following types of augment
mapping are supported:
• Augment Mapping AU-4
• Augment Mapping AU-3
• Mixed (AU-3 and AU-4) Augment Mapping
The supported modes of SDH are:
• AU-4-16c (VC4-16c)
• AU-4-4c (VC4-4c)
• AU-4 (VC4)
• AU-4 — TUG-3 — VC-3 — DS3
• AU-4 — TUG-3 — VC-3 — E3
• AU-4 — TUG-3 — TUG-2 — VC-11 — T1
• AU-4 — TUG-3 — TUG-2 — VC-12 — E1
• AU-4 — TUG-3 — TUG-2 — VC-11
• AU-4 — TUG-3 — TUG-2 — VC-12
• AU-3 — VC-3 — DS3
• AU-3 — TUG-2 — VC-11 — T1
• AU-3 — TUG-2 — VC-12 — E1
• AU-3 — TUG-2 — VC-11
• AU-3 — TUG-2 — VC-12
• AU-3 — VC-3 — E3
1 port OC-48/ 4 port OC-12/OC-3 + 12 port T1/E1 + 4 port T3/E3 CEM Interface Module Configuration Guide, Cisco
IOS XE Fuji 16.7.x (Cisco NCS 4200 Series)
8
This is the default augment mapping mode.
Note
Configuring SDH