Remote PHY architecture challenges and opportunities

Date of publication: 27.08.2018

In order to make DAA a reality we obviously need the right equipment that will allow MSOs to migrate to digital fiber nodes. To make the transition, operators have to get that first plant online, but this requires a different headend piece of equipment. Once that processing piece is ready to go, then the rest of the migration is fairly simple. While there are several DAA approaches, here are the two that dominate the conversation these days: Remote PHY and Remote MACPHY.

DAA with Remote PHY moves the DOCSIS PHY layer into the digital fiber node and the optical links between headend and node become digital. The big advantage of this approach is much better performance in the plant. What’s more, leaving the complex MAC layer inside the headend allows for better control and scale.

 

DAA with Remote MAC-PHY
places the MAC-PHY access layer functions in the access node. In this approach, apart from the benefits of digital fiber,
MSOs can free up a vast amount of room in the headend.

It is certain that the deployment of Remote PHY will change the way traditional HFC networks are installed, tested and maintained, especially as far as an optical layer is concerned. Remote PHY technology provides several major benefits to the HFC networks. Introducing digital fiber links allows MSOs to use solutions which are more cost-effective and well-established in the industry. Moreover, it allows for more data capacity due to enhanced spectrum reuse. On the other hand, operators today have to manage not only multiple CCAP cores, but also numerous nodes containing the RPDs that are connected in a leaf-spine architecture. Furthermore, the fiber nodes and CCAP cores may be provided by different vendors. In this case, it is crucial to ensure that all of the components are interoperable. Operators interested in migrating to Remote PHY are already facing the challenges of designing, deploying and managing the CIN, as well as the difficulties of supporting the existing services through the new infrastructure. Consequently, MSOs and their vendors are involved in diligent planning in order to provide the resources that will ensure a successful transformation of their networks.

Benefits:

  • Makes the most of the capabilities of DOCSIS 3.1 technology – more data capacity can be packed into the same portion of the spectrum
  • Supports Full Duplex DOCSIS – enables multi-gigabit upstream services from existing HFC plants
  • Employs lower cost and higher capacity optical Ethernet transport mechanisms
  • The standards are already specified
  • The products are in advanced stages of development

Challenges:

  • Management of multiple CCAP cores and nodes containing the RPDs connected in a leaf-spine architecture
  • Interoperability of the fiber nodes and CCAP cores

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