PL-3
Encyclopedia
PL-3 or POS-PHY Level 3 was the name of the interface that the Optical Internetworking Forum
's SPI-3
Interoperability Agreement is based on. It was proposed by PMC-Sierra
to the Optical Internetworking Forum
and adopted in June of 2000. The name means Packet Over SONET Physical layer level 3. PL-3 was developed by PMC-Sierra in conjunction with the SATURN Development Group
.
, supports reads and writes of memory addresses. The second broad category carries user packets over 1 or more channels and is exemplified by the IEEE 802.3
family of Media Independent Interface
s and the Optical Internetworking Forum
family of System Packet Interface
s. Of these last two, the family of System Packet Interfaces is optimized to carry user packets from many channels. The family of System Packet Interfaces is the most important packet-oriented, chip-to-chip interface family used between devices in the Packet over SONET and Optical Transport Network
, which are the principal protocols used to carry the internet between cities.
interfaces . A typical application of PL-3 (SPI-3) is to connect a framer device to a network processor. It has been widely adopted by the high speed networking marketplace.
There are several clocking options. The interface operates around 100 MHz. Implementations of SPI-3 (PL-3) have been produced which allow somewhat higher clock rates. This is important when overhead bytes are added to incoming packets.
were highly successful interfaces with many semiconductor devices produced to it.
Optical Internetworking Forum
The Optical Internetworking Forum is a non-profit, member-driven organization founded in 1998. It promotes the development and deployment of interoperable networking solutions and services through the creation of Implementation Agreements for optical networking products, network processing...
's SPI-3
SPI-3
SPI-3 or System Packet Interface Level 3 is the name of a chip-to-chip, channelized, packet interface widely used in high-speed communications devices. It was proposed by PMC-Sierra based on their PL-3 interface to the Optical Internetworking Forum and adopted in June of 2000...
Interoperability Agreement is based on. It was proposed by PMC-Sierra
PMC-Sierra
PMC-Sierra is a fabless semiconductor company which develops and sells devices into the communications, storage, printing, and embedded computing marketplaces.-Corporate history:...
to the Optical Internetworking Forum
Optical Internetworking Forum
The Optical Internetworking Forum is a non-profit, member-driven organization founded in 1998. It promotes the development and deployment of interoperable networking solutions and services through the creation of Implementation Agreements for optical networking products, network processing...
and adopted in June of 2000. The name means Packet Over SONET Physical layer level 3. PL-3 was developed by PMC-Sierra in conjunction with the SATURN Development Group
SATURN Development Group
The SATURN Development Group was an important industry forum that enabled the specification of chip-to-chip interfaces for the communications industry. It was co-founded in 1992 by PMC-Sierra and Sun Microsystems. Several significant specifications were completed through its actions including...
.
Context
There are two broad categories of chip-to-chip interfaces. The first, exemplified by PCI-Express and HyperTransportHyperTransport
HyperTransport , formerly known as Lightning Data Transport , is a technology for interconnection of computer processors. It is a bidirectional serial/parallel high-bandwidth, low-latency point-to-point link that was introduced on April 2, 2001...
, supports reads and writes of memory addresses. The second broad category carries user packets over 1 or more channels and is exemplified by the IEEE 802.3
IEEE 802.3
IEEE 802.3 is a working group and a collection of IEEE standards produced by the working group defining the physical layer and data link layer's media access control of wired Ethernet. This is generally a local area network technology with some wide area network applications...
family of Media Independent Interface
Media Independent Interface
The Media Independent Interface was originally defined as a standard interface used to connect a Fast Ethernet MAC-block to a PHY chip.The MII design has been extended to support reduced signals and increases speeds...
s and the Optical Internetworking Forum
Optical Internetworking Forum
The Optical Internetworking Forum is a non-profit, member-driven organization founded in 1998. It promotes the development and deployment of interoperable networking solutions and services through the creation of Implementation Agreements for optical networking products, network processing...
family of System Packet Interface
System Packet Interface
The System Packet Interface family of Interoperability Agreements from the Optical Internetworking Forum specify chip-to-chip, channelized, packet interfaces commonly used in synchronous optical networking and ethernet applications. A typical application of such a packet level interface is between...
s. Of these last two, the family of System Packet Interfaces is optimized to carry user packets from many channels. The family of System Packet Interfaces is the most important packet-oriented, chip-to-chip interface family used between devices in the Packet over SONET and Optical Transport Network
Optical Transport Network
ITU-T defines an Optical Transport Network as a set of Optical Network Elements connected by optical fibre links, able to provide functionality of transport, multiplexing, switching, management, supervision and survivability of optical channels carrying client signals...
, which are the principal protocols used to carry the internet between cities.
Applications
It was designed to be used in systems that support OC-48 SONETSonet
Sonet may refer to:* Sonet Records, European record label* Synchronous optical networking * Saab Sonett...
interfaces . A typical application of PL-3 (SPI-3) is to connect a framer device to a network processor. It has been widely adopted by the high speed networking marketplace.
Technical details
The interface consists of (per direction):- 32 TTL signals for the data path
- 8 TTL signals for control
- one TTL signal for clock
- 8 TTL signals for optional additional multi-channel status
There are several clocking options. The interface operates around 100 MHz. Implementations of SPI-3 (PL-3) have been produced which allow somewhat higher clock rates. This is important when overhead bytes are added to incoming packets.
Trivia
The name is an acronym of an acronym of an acronym as the P in PL stands for "POS-PHY" and the S in POS-PHY stands for "SONET" (Synchronous Optical Network). The L in PL stands for "Layer".PL-3 in the marketplace
PL-3 and SPI-3SPI-3
SPI-3 or System Packet Interface Level 3 is the name of a chip-to-chip, channelized, packet interface widely used in high-speed communications devices. It was proposed by PMC-Sierra based on their PL-3 interface to the Optical Internetworking Forum and adopted in June of 2000...
were highly successful interfaces with many semiconductor devices produced to it.