Passive Optical LAN Technical Overview & Benefits

Why Passive Optical LAN

Optical Line Terminal

The Optical Line Terminal (OLT) resides in the datacenter or core network. It connects to the core switch using traditional Ethernet pluggables.

  • Consists of modular PON cards
  • Provides redundant switching, control, and power capability
  • Each PON port typically connects 32 ONTs
  • Transmits Ethernet to end user ONTs on one wavelength (1490 nm)
  • Receives Ethernet from end user ONTs on a separate wavelength (1310 nm)
  • Utilizes 128 bit AES encryption for downstream (broadcast) traffic
  • Utilizes Time-Division-Multiple-Access (TDMA) for upstream traffic

Passive Optical Splitter

Passive Optical Splitters connect to each PON port and replicate traffic downstream (to the end user’s ONT) while combining end user traffic in the upstream direction.

  • Requires no power or cooling (hence the word “passive”)
  • Can be placed anywhere in the midspan of the fiber network
  • Typically deployed in above-ceiling fiber zone boxes near end user work areas
  • No need to perform cross connects after initial installation (networks are logically assigned)
  • The splitters and fiber components will last for decades

Optical Network Terminal

The ONT serves as the end user interface to the network.

  • Typically powered by a low voltage power brick
  • Converts the single mode fiber optical signal to RJ-45 Ethernet interfaces
  • Various models provide anywhere from 1 to 24 Ethernet Ports
  • Various models support Power-over-Ethernet (POE)
  • Supports VLAN, 802.1x, and QoS
  • Can be deployed on the desktop, wall-mounted, or rack-mounted

Passive Optical LAN Technical Overview

Technical Advantages

Passive Optical LAN is a new application of a proven access network solution. It is a better way to structure a LAN, because:

  • It flattens the Local Area Network
  • It simplifies network moves, adds, and changes
  • Is not limited by the distance and bandwidth constraints of twisted pair networks
  • Is secure by design, based on optical fiber and built-in encryption

Economic Advantages

Passive Optical LAN provides substantial savings in CapEx and OpEx compared to legacy LAN designs.

  • Can eliminate wiring closets
  • Eliminates the need for midspan electronics, power, and cooling infrastructure
  • Uses smaller, lighter, less expensive cables to reduce pathway and space requirements
  • Virtually eliminates the need to refresh cabling infrastructures
  • As technology evolves, only the active endpoints need a refresh

Who Benefits?

  • Design engineers
  • Architects
  • Building owners
  • CIOs and IT departments
  • End users

Passive Optical LAN Distances

Passive Optical LAN vs. Legacy Architectures

Passive Optical LAN architectures provide tremendous improvements in the design and deployment of local area networks. Composed almost entirely of single-mode fiber optic cable, a Passive Optical LAN can span for 20 km (12.5 miles) or more depending on the optics and splitter ratios deployed. While not all networks may need to span such distances, it is particularly advantageous for multi-story buildings and campus networks where mid-span switching equipment is eliminated entirely. Even single building networks can take advantage of these flexible distances by no longer requiring a telecommunications closet or switch every 300 feet as is the case with legacy network architectures.

  • Passive Optical LANs can span 20 km (12.5 miles) or more
  • Reduces the operational footprint (less complexity)
  • Allows RF video deployment on a converged fiber network (no need for hard-line coax or amplifiers)

Passive Optical LAN “POL 101”Explainer Video

Watch our 1-hour Passive Optical LAN explainer webcast replay that covers the basics “POL 101” for the technology. This video-on-demand explains Optical Line Terminals (OLT), Optical Network Terminals (ONT), fiber infrastructure, passive optical splitters, powering and much more.

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