Hardware Disaggregation: Demand Extending Beyond Expectations

Rick Talbot
Rick Talbot

Summary Bullets:

  • ICPs are deploying disaggregated solutions across their networks; data center operator interest in specialized DCI solutions for data centers also reflects this trend.
  • AT&T appears to have taken up the trend as it deploys disaggregated OLTs and proposes disaggregation of additional network equipment.

As I pointed out in a blog post last month, the capabilities introduced by SDN set the stage to present a radical possibility for the network: network element disaggregation (or, in the rest of this post, simply disaggregation). Though this concept would appear to be strictly in the purview of the academic community, several large network operators have called for disaggregation (either by name or perhaps by other names) over the past year. Demand for disaggregation exists beyond the theoretical.

Google provided an early example of disaggregation when it developed and deployed its B4 SDN network, replacing off-the-shelf routers with do-it-yourself (DIY) network switches. The company expanded these concepts while it developed succeeding versions of its data center network, as it presented at the ACM SIGCOMM 2015 conference last month. For these designs, Google optimized combinations of best-of-breed components for specific portions of its intra-data center network rather than employ commercial Ethernet (or data center fabric) switches. Facebook indicated that it was moving in a similar direction with its ‘6-pack’ open hardware modular switch. Facebook is also pushing disaggregation into its optics, especially within the data center as it seeks to purchase directly from optical module manufacturers. At OFC 2015, Microsoft rattled optical systems vendors by participating in the Consortium for On-Board Optics (COBO), clearly participating in module design, and proposed an ‘open line system’ (OLS), which would eliminate electrical OTU switching. These moves indicate that the Internet content providers (ICPs) are favoring disaggregation.

While the ICPs are embracing the disaggregation concept, many data center operators appear to be following a similar track as they express interest in transport-only data center interconnection (DCI) platforms. On the other hand, if any telecommunications business segment would hold on to the converged packet-optical network, surely it would be the traditional telcos. After all, Verizon issued the original packet-optical transport platform RFP in 2007, and awarded Ciena and Cisco business for deploying next-generation metro packet-optical transport platforms in early 2015.

However, even the telcos are seeking to virtualize network functions in next-generation central offices that will look much like data centers (and use techniques that are employed by perhaps their most threatening competitors, the ICPs). AT&T, which is developing its virtualization capabilities through the Domain 2.0 initiative, recently proposed disaggregation by name at the Open Networking Summit (ONS) 2015, and described its disaggregation initiatives in an associated blog post. In the post, AT&T reveals that the company’s new GigaPower (U-verse) service – which provides 1 Gbps ultra-broadband connectivity to end users – will be progressively enabled by implementing virtualized network functions on COTS servers. AT&T’s plans are to move toward a virtualized OLT (vOLT) solution in which it will ‘break out’ subsystems of the OLT, for example, by releasing commodity hardware specs into open source (via the Open Compute Project), with the idea of virtualizing the GPON OLT line cards. The goal of AT&T’s vOLT initiative is fairly straightforward: generate additional CapEx and OpEx savings – i.e., through lower power consumption and more efficiency network scaling. However, AT&T’s disaggregation targets are not simply OLTs; the blog post also calls out broadband network gateways and Ethernet aggregation switches for disaggregation.

The move towards disaggregation was probably to be expected of the ICPs, since they appear to have a DIY gene anyway, and data center operators were bound to follow since their operating environments are practically identical (scale being the major difference). However, the rapid development of telco interest in disaggregation (at least by AT&T) is surprising, and could signal the beginning of a massive disruption of the systems vendor marketplace.

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