CHAPTER
20-1
Ethernet Card Software Feature and Configuration Guide, R7.2
January 2009
20
POS on ONS Ethernet Cards
This chapter describes packet-over-SONET/SDH (POS) a nd its implementation on ONS Ethernet card s.
This chapter contains the following major sections:
POS Overview, page 20-1
POS Interoperability, page 20-2
POS Encapsulation Types, page 20-4
POS Framing Modes, page 20-7
POS Characteristics of Specific ONS Ethernet Cards, page 20-7
Ethernet Clocking Versus SONET/SDH Clocking, page 20-11

POS Overview

Unlike Asynchronous Transfer Mode (ATM) and Frame Relay, Ethernet was not originally designed for
interfacing with SONET/SDH. Ethernet data packets need to be framed and encapsulated into a
SONET/SDH frame for transport across the SONET/SDH network. Th is framing and encapsulation
process is known as POS.