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Middle-mile Key Buying Criteria: What Makes for a Robust Broadband Transport Solution?

Kurt Raaflaub

June 13, 2024
By Kurt Raaflaub
Director, Solution Marketing

As internet service providers (ISPs) build out new broadband networks and upgrade existing ones, they also need to ensure they can connect to a robust middle-mile optical networking solution. In this blog, I will explore some key broadband transport solution considerations that will circle around the following solution attributes:

  • Easy to install, operate, and maintain
  • Lower power consumption and space requirements
  • N x 100G network capacity that extends for 1,000+ km without signal regeneration
  • Compatibility to transport existing services using legacy SDH/SONET transport protocol
  • Capability to meet the low latency and network timing distribution needs of new applications
  • Suitability to operate within remote outside plant (OSP) settings
  • Network fault tolerance, lightning strike protection, and link restoration

Diagram of Broadband Access, Middle Mile Broadband Transport and Internet

Matching Middle-mile Solution Capability with Operator Needs

Community leaders and service providers need to consider a range of community use cases as they invest in the future network. When looked at in aggregate, these community use cases cover a wide range of operational and business needs. Due to this, network operators, before building out new and/or upgrading existing middle-mile networks, should look at six considerations as they source a robust middle-mile a.k.a. broadband transport solution. These considerations are:


Rapid time to market demands operational simplicity

The ability to rapidly respond to market opportunity is always a key concern, especially for rural U.S. ISPs. In the U.S., government-funded infrastructure buildouts must be completed within five years, and the timer has started. Stipulated project completion timelines are as follows: 40% of project miles are to be completed by the end of the second year, 60% by the end of the third year, and 80% by the end of the fourth year. Due to this, many network operators will lean on well-understood technologies and proven platforms that offer simplified network deployment, operation, and maintenance.

This could mean using fully vetted solutions with a strong track record like the Infinera XTM Series or newer solutions with highly differentiated value propositions like programmable coherent pluggable optics. Infinera’s ICE-X intelligent coherent pluggable optics are a good example. By plugging these intelligent coherent pluggables into a switch or router, network operators can reduce power consumption and space requirements.


High return on investments means supporting more services on less fiber

Over 90% of the cost of any broadband project is the installation of the optical distribution network (ODN). Optical networking platforms should be chosen that maximize the capability (capacity and/or reach) of these same ODN resources. For example, current N x 10 Gb/s transport solutions must not come with lower reach capabilities when upgraded to support N x 100 Gb/s services; they need to come with more reach – I mean, 1,000 km more. It is not about balancing the need to deliver more rate or more reach; it is about being able to deliver better services to more locations, to more people.

Next-generation ZR+ coherent optical pluggables provide 400G broadband transport across 1,000 kilometers. By leveraging subcarrier-based Open XR Optics Forum-compliant ICE-X intelligent coherent pluggable optics, service providers can also deliver high-capacity bidirectional services across a single strand of fiber. Single-strand ODN resources previously used for FTTH services can also simultaneously deliver N x 25G and N x 100G business services for wholesale, large enterprise, 5G xHaul, or middle-mile extension.


Legacy service support means operating one network, not two

Many businesses continue to use access solutions that connect to the network via legacy technologies using lower-speed interfaces. These revenue-generating, mission-critical services need to be transported across middle-mile networks. New middle-mile networks need to support legacy services and the smooth migration of legacy time-division multiplexing networks to a common transport network that also fulfills strict synchronization and availability requirements.


Low network latency means better quality of experience

Industry 4.0, 5G xHaul, and grid modernization initiatives have strict latency needs and varying levels of capacity requirements. Robust middle-mile networks should have the scale and flexibility to support these unique applications, in addition to emerging latency-sensitive applications such as telesurgery. Reducing middle-mile network latency is also important for the many rural ISPs that connect to the internet via distant internet exchange points (IXPs). This means higher latency that translates to poor quality of experience, like slow website performance.

The Infinera XTM Series supports superior low-latency and synchronization capabilities that are vital in mobile backhaul, especially as mobile operators roll out 5G xHaul networks.


Greater service continuity means lightning protection and link restoration

Middle-mile and backhaul solutions are required to aggregate traffic from hundreds of sites, many of which carry mission-critical communication. Service continuity needs to be preserved. The network needs to be self-healing, as the time and cost to repair fiber cuts and network faults increases with remote installations commonly found in rural networks. Those operators using aerial fiber must consider the need for lightning tolerance, as a strong lightning event can be known to take down a large service area.


Remote OLT deployments demand hardened solutions

Next-generation optical networking solutions’ ability to support rural broadband, 5G densification, and grid modernization applications will be a strong consideration – specifically, the need to be deployed remotely within outdoor enclosures. This will require Layer 0 through Layer 2 solutions to be environmentally hardened, supporting a wider range of operating temperatures, known as I-temp. The space requirements and noise output levels will also be considered important.

Enabling Communities Means Transforming the Middle Mile Network


When all middle-mile network requirements and community use cases are considered, optical networking solutions based on modern coherent optical technologies make the short list due to their ability to support the full range of buying criteria. To fully enable communities, the middle-mile network will need to be transformed. As access networks are upgraded to support greater levels of bandwidth consumption, network operators understand they will need their middle-mile transport networks to keep pace. If they don’t, it will impact the networks’ ability to support more services in more places with the customer experience needed to provide a positive impact on the way we work, live, and play.