H3C Technologies H3C SR8800 - Manual (Page 29)

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Configuring POS interfaces
Overview
SONET
Synchronous Optical Network (SONET), a synchronous transmission system defined by ANSI, is an
international standard transmission protocol. It uses optical transmission where transmission rates form a
sequence of STM-1, STM-4, and STM-16, each four times the immediate lower level. Because signals are
synchronous, SDH can multiplex multiple signals conveniently.
SDH
Synchronous Digital Hierarchy (SDH), defined by the CCITT (the ITU-T at present), uses a SONET rate
subset. SDH adopts synchronous multiplexing and allows for flexible mapping structure. It can add or
drop low-speed tributary signals to or from SDH signals without a large amount of
multiplexing/demultiplexing devices. This reduces signal attenuation and investment in network devices.
POS
Packet over SONET/SDH (POS) is a technology popular on WAN and MAN. It can support packet data
such as IP packets.
POS maps length-variable packets directly to SONET synchronous payloads and uses the SONET
physical layer transmission standard. It offers high-speed, reliable, and point-to-point data connectivity.
The POS interfaces on your router support PPP, HDLC and FR at the data link layer and IP at the network
layer. Depending on the subcards of a POS interfaces, its transmission rate can be STM-1, STM-4, and
STM-16, each four times the immediate lower level.
Configuring a POS interface
Before you configure the link layer and network layer protocols on a POS interface, you must configure
its physical parameters.
Configuring a POS interface
To configure a POS interface:
Step Command Remarks
1. Enter system view. system-view N/A
2. Enter POS interface view. interface pos interface-number N/A