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Linux powers “world’s first” GPON/GE-PON SoCs

May 7, 2007 — by LinuxDevices Staff — from the LinuxDevices Archive — 23 views

Conexant claims to be sampling the “world's first” system-on-chip (SoC) processors for “GPON/GE-PON residential gateways” (gigabit/gigabit Ethernet passive optical networking). The “Xenon-IIIG” GPON and “Xenon-IIIE” GE-PON chips come with Linux, and support both FTTH and FTTN (fiber-to-the-home/node) applications, Conexant said.

GPON (ITU G.984) is most commonly used in “fiber-to-the-home” applications, with a single fiber being divided by passive (non-powered) splitters into 32 branches. GE-PON (IEEE 802.3ah) adds an Ethernet layer, for “simplicity” and “cost-effectiveness,” according to Conexant. The company previously shipped an ARM9-powered “Xenon-II” GE-PON chip; however, the Xenon-IIIG appears to be its first-ever offering for plain GPON networking.

Both Xenon-III chips can process upwards of 10 gigabits per second, according to Conexant, making them suitable for “cost-effective” delivery of triple-play services (voice, video, and data) over fiber optic cables. They can be used standalone in FTTH applications, or combined with VDSL (very high-speed) DSL CO (central office) and CPE (customer premises equipment) for FTTN applications.

Touted features include:

  • Xenon-IIIE and Xenon-IIIG are “pin- and software-compatible”
  • Xenon-IIIE complies with China Telecom's EPON specification
  • Tested with optical line terminal (OLT) end-product manufacturers to “ensure interoperability on both sides of the connection”
  • Full line rate performance at 2.4 Gb/s downstream and 1.25 Gb/s upstream
  • Physical layer encryption, security, bridging, and routing required to enable quality of service (QoS) in IP video applications
  • Integrated functionality for four concurrent voice-over-IP channels, three-way calling, and a T.38 fax demodulator
  • “Superior QoS, robust security, and complete management of a customer premises device from the central office”
  • Interfaces for key home networking technologies, including Multimedia over Coax Alliance (MoCA), HomePNA, HomePlug A/V and gigabit Ethernet

On the software side, the Xenon-III SoCs are bundled with an open source-based Linux BSP (board-support package), along with Conexant's “ISOS” (integrated system-on-silicon) protocol stacks and “support for customers' own software stacks.” The provided BSP and stacks are said to enable software reuse from ADSL and VDSL product designs.

According to Akram Atallah, Conexant's GM of broadband access, “Operators worldwide are planning to use PON technology for next-generation network upgrades to improve their ability to deliver bandwidth-intensive services such as video-on-demand and IPTV.”

Aileen Arcill, senior research analyst at IDC, added, “PON is becoming a viable broadband access technology to be implemented in residential gateways, which are critical to driving mass subscriber growth.”

Conexant also offers CO and CPE products for ADSL2plus, SHDSL, and VDSL2. It claims to have shipped “more than 200 million DSL ports,” and to have shipped the first 12, 26, and 40 megabits per second (Mbps) ADSL chipsets.


The CX95202 Xenon-IIIG and CX95203 Xenon-IIIE SoCs are sampling now, packaged in an 824-pin plastic ball grid array (PBGA). They are expected to ship in volume in July, priced at $30 in quantities of 10,000.

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