About Joe Mocerino

As Principal Solutions Architect, Joe engages wireless and wireline operators and partners in the mobile xHaul ecosystem. His mobile transport expertise includes fronthaul, backhaul, CPRI, TSN, packet, OTN, and SONET technologies. Joe has designed, developed, and deployed wireless and wireline transport solutions that maximize capacity and coverage for high-value automated operation. A fan of music and fitness, Joe enjoys playing guitar in his home recording studio and cycling.

Putting It All Together: The Power of Time-Sensitive Networking (TSN)

Service providers are rapidly transforming their networks to deliver competitive and affordable 5G services, and cell site densification is one of the key factors in the eventual success of 5G. But deploying fiber and then maximizing bandwidth capacity to so many cell sites can be an expensive proposition. Compared to active WDM-based offerings, Ethernet-based mobile fronthaul using Time Sensitive Networking (TSN) can significantly reduce the total cost of ownership, with up to 50% lower capital costs, 90% turn-up time savings, 75% footprint reduction, and simplified spares and inventory management.

Time-Sensitive Networking

Standards have been developed that are crucial to the success of mobile fronthaul. The IEEE 802.1 Time-Sensitive Networking set of standards extends Ethernet to support time-sensitive traffic, with stringent bounds on loss, end-to-end delay (latency), and delay variation (jitter). This standard is intended to combine the deterministic performance and reliability of circuit-switched technologies with the speed and scale of Ethernet. In this blog, we dive into TSN as well as IEEE 802.1CM, the TSN profile for mobile fronthaul.

Four key components of TSN serve to support real-time communications:

1.            Timing and synchronization

2.            Bounded low latency

3.            High availability and reliability

4.            Resource management

Timing and Synchronization

The 5G RAN requires greater timing accuracy and precision than 4G. Another difference with 4G is that the remote radio heads (RRH) will more likely derive timing from the network, instead of from a GPS clock located at the cell site (a more expensive option). Hence the timing network needs to be planned properly, the number of hops between the clock and the radios minimized, and the time error introduced at each hop minimized. Amongst other considerations, the required fronthaul and associated midhaul/backhaul networks’ timing accuracy and latency tolerance will depend on the 5G RAN functional splits that includes CPRI and eCPRI architectures.

The IEEE 1588v2 Precision Time Protocol (PTP) is used to provide timing and synchronization to the 5G radio unit (RU). Ethernet switches in a TSN network act as telecom boundary clocks (T-BC), processing and passing on timing information, correcting errors, and synchronizing traffic accordingly.  TSN networks use the IEEE 802.1AS timing protocol, which is a subset of PTP with additions.

Bounded Low Latency

An Ethernet-based mobile fronthaul network will likely transport multiple traffic types:

  • CPRI, which is encapsulated with Ethernet using IEEE 1914.3 Radio over Ethernet
  • eCPRI, which is already packet-based, from 5G RU to the DU/CU
  • Alarms, environmental monitoring, and operations data from the cell site to the NOC
  • Converged service offerings, such as business Ethernet services

Within these traffic types, TSN implements a variety of quality of service (QoS) mechanisms at the switch level to deliver the zero congestion loss, deterministic latency, and minimal jitter required:

Credit-based shaper IEEE 802.1Qav Smooths out packet transmissions; reduces bursting and bunching. A similar algorithm is used in Carrier Ethernet networks.
Frame Pre-emption IEEE 802.1Qbu IEEE 802.3br Critical, express frames can interrupt transmission of lower priority frames. Pre-empted frames are not lost.
Time-Aware Shaper (TAS) IEEE 802.1Qbv Implements fixed time slices with 8 traffic priorities, the highest for time-critical control data (with a worst-case latency of 100 µs over 5 hops).
Cyclic Queuing and Forwarding (CQF) IEEE 802.1Qch The use of double buffers synchronizes transmissions in a cyclic manner, resulting in bounded latency that is independent of the network topology.
Asynchronous Traffic Shaping (ATS) IEEE 802.1Qcr Improves link utilization for mixed traffic types. The techniques above handle deterministic traffic very well, but are less efficient for traffic with arbitrary profiles. ATS remedies this.

In addition to these standards, IEEE 802.1CM includes standard TSN profiles for fronthaul that enable the transport of fronthaul streams, specifically with regards to:

  • CPRI, eCPRI use cases, requirements, and synchronization, as well as the RBS (Radio Base Station) splits
  • Packet networking and synchronization characterizations for Bridging and TSN features
  • Leveraging the telecom profile of IEEE 1588v2

The result is two 802.1CM profiles that apply to both CPRI and eCPRI, and meets the requirements of TSN for fronthaul:

  • Profile A: Simple and based on the strict priority of CPRI and eCPRI traffic
  • Profile B: Leverages frame pre-emption (IEEE 802.3br & 802.1Qbu) to maintain strict priority traffic with pre-emptible Ethernet traffic

High Availability and Reliability

A robust network must cope with power outages, switch failures and fiber cuts. But Ethernet networks are bridged packet networks, not fault tolerant SONET/STM rings. Thus several network level mechanisms have been built into TSN to ensure end-to-end availability and reliability:

Frame Replications and Elimination for Reliability (FRER) IEEE 802.1QCB Duplicate copies of each frame are transmitted over separate paths across the network, and 1+1 or 1+N redundancy is possible. At the other end, the packets are merged and/or discarded. Note that this does not rely on link failure detection or switchover, as in the case of SONET, but rather on duplicating packets.
Path Control and Reservation (PCR) IEEE 802.1Qbu Configures multiple paths through the network for frame replication. Multiple paths in Ethernet networks are usually avoided in order to prevent bridging loops.
Per-Stream Filtering and Policing (PSFP) IEEE 802.1Qci Prevents traffic overloads that may stem from bandwidth violations, malfunctions or malicious attacks such as Denial of Service (DoS).

Operating at a network level, these protocols lend themselves to a software-defined networking (SDN) approach, with a centralized network controller controlling the TSN switches.

Resource Management

The concept of paths across the network is analogous to traditional connection-oriented circuits, and TSN enables centralized network management of paths and devices:

Stream Reservation Protocol (SRP) IEEE 802.1Qat SRP provides end-to-end management of traffic streams, allocating the bandwidth resources required at each switch, calculates worst-case latency, and monitors stream metrics.
SRP Enhancements IEEE 802.1Qcc Improves the Stream Reservation Protocol for administration of large TSN networks with improvements to centralized reservation and scheduling, remote management, and reservation requests.
YANG data model IEEE P802.1Qcp Network management, device configuration, and status reporting of switches.

Putting It All Together: Introducing the HFR flexiHaul™ M6424

The M6424 is an optimized, TSN switch for fronthaul that can be deployed at cell sites, hub sites, and central offices, for aggregating 4G CPRI, 5G eCPRI, and Ethernet traffic onto the transport network. This single aggregation switch offers relief from fiber exhaustion, with no WDM optics required, simplifying deployment and reducing costs.

The M6424 supports the IEEE 802.1CM profiles for fronthaul with frame pre-emption, and is packed inside a 1RU hardened chassis.

For more information about the Fujitsu Smart xHaul Solution, visit this web page or call your Fujitsu Network Communications Sales Manager today.

Virtualized Routers for 5G Transport: Webinar Replay Now Available

If you want to learn more about how virtual routers, or vRouters, will be used to meet the demands of 5G transport and other next-gen services, check out the on-demand recording of the webinar, “Virtual Routers for Flexible, Future-Proof 5G Transport.” Click here to listen to the free recorded session, and you’ll also be able to download the presentations, a special market report by IHS Markit Executive Director Heidi Adams, and a number of other resources on this topic.

The 60-minute webinar, co-sponsored by Fujitsu, first aired on December 10, 2019, and was hosted by IHS Markit, the London-based data and information services firm. Allen Tatara, Senior Manager at IHS Markit, served as moderator. A Q&A session followed the presentations.

Presenters included: Joseph Mocerino, Principal Solutions Architect, Optical Networking, Fujitsu Network Communications; Heidi Adams, Executive Director, Network Infrastructure Research, IHS Markit; and Hugh Kelly, Vice President of Marketing, Volta Networks.

The global audience included network operators, service providers, equipment manufacturers, and enterprise end users. The presentations and Q&A covered a number of topics, including:

  • The market trends driving IP network evolution;
  • An introduction to virtualized routing architectures and virtual routers;
  • The strategies for supporting the delivery of network slices for 5G services;
  • The challenges facing this network evolution; and
  • Several use cases and deployment examples.

5G will bring the promise of ultra-broadband speeds, ultra-reliable low-latency services, and the ability to massively scale communications for a wide range of devices and next-gen applications like Internet of Things (IoT), Smart Cities, telemedicine, and connected cars. But these services will also place new demands on the underlying IP transport infrastructure impacting how we will design our networks in the future.  

In particular, the way routing is delivered into the network must evolve. In response, the implementation of new solutions – such as cloud-native virtualized routers – are emerging to enable higher-capacity, more flexible, and less costly IP networks. In fact, a recent survey by IHS Markit revealed that 95% of service providers had plans to virtualize at least one or more of their network functions or applications. All these topics and more are covered in the webinar, so don’t miss this opportunity to learn about how cloud-native virtualized routers will play a leading role in meeting 5G transport requirements. Click here to listen to the free recorded session and download additional market insights on these emerging topics.

Top Four Takeaways About 5G Transport You Need to Know

With the promise of massively increased speed and capacity, there is a lot riding on the success of next-generation 5G technology. To be more accurate, one might say there is a lot riding on the 5G transport network specifically, given the critical role that transport will play in enabling high-bandwidth, ultra-reliable and ultra-low latency applications for 5G.

As communication service providers (CSPs) urgently plan their commercial 5G deployments, the most important first step is mapping out the backhaul, fronthaul and midhaul transport architectures to ensure the best possible customer experience. In order to gain valuable insight into the current and future state of 5G transport, Fujitsu partnered with analyst firm Heavy Reading to conduct an in-depth survey of CSPs from around the world. Here are just a few noteworthy findings from this comprehensive 5G research.

5G is open for business —Survey results clearly indicate interest in moving toward open interoperability with 5G. A large majority of respondents reported that RAN interoperability between radio unit (RU) and baseband unit (BBU) equipment was at least “very important” to them, with a sizeable number citing RAN interoperability as a “critical” requirement.

Appetite for bandwidth —According to the survey, the need for more capacity is the primary driver behind the desire to upgrade midhaul and backhaul networks. In fact, nearly 30% more respondents cited capacity versus those that selected latency, the second highest response.

A central theme —Although some CSPs adopted centralized RAN (C-RAN) with advanced 4G, for most operators this approach means transitioning to a completely new architecture for 5G. Despite the challenge that represents, survey results show growing interest in RAN centralization across a number of regions.

When do we want it — To meet expectations for commercial 5G services, CSPs will first need to have a robust transport network in place. When asked in what timeframe they will begin launching 5G, more than 50% of respondents said they expect to launch initial mass-market services by 2020. To learn more about the state of 5G transport, click here to download a complimentary copy of the 2019 Heavy Reading Survey: “Operator Strategies for 5G Transport.”

Network Slicing Made Simple

To deliver on the promise of 5G, this next-generation technology will enable multiple new service streams virtualized through a common infrastructure. With all the different use cases for 5G, these services will have diverse performance requirements, which adds to the challenges of delivering them in an efficient way. To overcome these challenges, tomorrow’s networks will rely on network slicing.

The 5G radio consists of three distinct elements as defined by the Third Generation Partnership Project (3GPP): radio unit (RU), distribution unit (DU) and central unit (CU). In the 5G New Radio (5G NR), multiple RUs hand off data to the DU. Network slicing begins within the DU by identifying specific services and allocating virtualized, isolated resources. The transport network interoperates with the DU and CU for dynamic service delivery and resource allocation, while the network operation uses multiprotocol label switching (MPLS) segment routing for dynamic establishment of resources. 

There is, however, a simpler and more cost-effective way of engineering and maintaining the MPLS segment routing elements. This involves physically separating the control and user planes using disaggregation, and operating the control plane in the cloud. Contrasting the cloud control plane to a traditional router will illustrate the benefits of this approach. 

A traditional router platform consists of an integrated control and user plane, in the form of a chassis and plug-in cards. These chassis come in multiple sizes based on performance and capacity supported. Each chassis dimension has integrated control and user plane regardless of the chassis size. Therefore, scaling is limited to that fixed dimension, meaning they always scale up to a limit. This means that — from Day One — the platform will typically only run at 20 to 30 percent capacity, but will still have to reserve the full footprint, power and thermal allocation of full loading. This is a very inefficient use of CAPEX. Furthermore, each of the deployment sites runs the risk of under- or over-engineering the capacity. Too small a dimension with an under-capacity site results in loss of revenue through unfulfilled demands, while an over-engineered site is an inefficient use of capital.

Control Capacity in the Cloud

Alternatively, the disaggregated approach consists of a programmable, purpose-built blade forming the MPLS-segment routing common infrastructure, and a decoupled virtual control plane in the cloud. When a new service is required, a virtual routing instance is generated in the control plane and provisioned throughout the virtual network, including resilient alternate pathways, end-to-end, based on the service level agreement (SLA).

Once calculated for the virtual network, the programming is pushed down into the common infrastructure. These cloud micro-services offer real protocol isolation per virtual router instance, where each protocol is running in its own container and brought together as one virtual router application instance. Multiple virtual router instances with full isolation can share the same network element hardware, offering a very CAPEX-efficient scaling operation. We refer to this as a scale-out approach via linear resource scaling, resulting in better infrastructure utilization versus traditional routers. 

Applying the cloud control plane approach to network slicing based on upcoming 5G services offers simplified operations and capacity scaling using virtualization to dynamically allocate and provision services to customers. As services are provisioned, the virtual routing instances are provisioned end-to-end for each service and customer on a global basis, then pushed down to the programmable network elements running the user plane.

This simplified operation offers full resource guarantees with reduced operational complexity, resulting in faster time to market/revenue return, while lowering the cost per bit using a capacity efficient virtualized network. This allows for the construction of one common infrastructure where individual network elements are minimized and right sized for capacity with multiple virtual networks, enabling many diverse service use cases to fully realize the potential of 5G.

The Reality of Delivering the 5G Vision

With the start of 2019, the era of 5G is officially here… or is it? Are you ready? While a few early market leaders are already hyping 5G services, most service providers are still making plans. And as the build-out begins, the reality of deploying complex new architectures is introducing a variety of challenges.

Due to the increased speed and capability that 5G promises, service providers can expect mobile subscribers to consume more and more data, particularly rich multimedia content. Add to that the flood of device-to-device communications expected with the Internet of Things (IoT), as well as new use cases for the smart home enabled by fixed wireless access, and it’s easy to see that substantially greater capacity, scalability, reliability and performance will be needed — from the first mile all the way to the edge.

Intelligent RAN Plan

Next-generation 5G networks will require robust transport infrastructure, including a dense radio access network (RAN) architecture with distributed intelligence. This increasing densification means more advanced topologies in the access part of the transport network, as well as evolved fronthaul, midhaul and backhaul (i.e., X-Haul) interfaces.

As the 5G RAN becomes increasingly virtualized, service providers will be able to dynamically support a range of use cases with varying demands using SDN control and orchestration. Plus, a key benefit of this virtualization is the opportunity to disaggregate the optical transport network, simplifying the evolution to an integrated and modular 4G/5G network that is highly programmable.

However, X-Haul deployment plans will be highly dependent on the varying capacity needs and latency sensitivities of the specific use cases to be supported, requiring careful consideration of many different factors.

Vision to Reality

The potential for significant revenue from diverse 5G services is very real. And with a robust transport network capable of adaptively handling multiple open radio interfaces, network latencies and virtual infrastructures, your network will be able to support countless devices and applications, delivering the full 5G experience.

Yet, the complexities of next-generation architecture mean that service providers are essentially in uncharted waters as they transform this vision into reality, requiring them to fundamentally rethink network design and deployment. For this reason, Fujitsu is working closely with leading network service providers to help them plan, design and deploy 5G networks that will allow them to deliver new services they can monetize immediately, while preparing for more evolved use cases in the future.

To help other service providers learn from our real-world experience, we’ve published a paper entitled “Transporting 5G from Vision to Reality” that examines 5G transport challenges, the evolution of the RAN architecture, best practices for design and deployment, early business model opportunities and a vision for the future.  Click here to download this informative paper.

5G Transport: The Impact of Millimeter Wave and Sub-6 Radios

Part two in a blog series about how Fujitsu is bringing the 5G vision to life

As communications service providers (CSPs) prepare to deploy 5G, a number of factors will need to be considered as they plan their radio access network (RAN) architecture. An important aspect of this planning is an understanding of the 5G radio interface (NR) specifications and spectrum options.

Both millimeter wave (mmWave) and sub-6 GHz radio architectures have a fronthaul, midhaul and backhaul in terms of transport. However, the differences in the coverage aspects of these two radio types will define the network topology.

The high frequencies of mmWave radios result in reduced coverage of a given area, requiring a more dense deployment outside of traditional cell towers. The mmWave radios will be deployed in a small cell type of configuration, since a large number are required to cover a given area.  In urban areas, the dense deployment of mmWave radios will most likely be on street lamps, and the side or top of buildings. Sub-6 radios, however, enable coverage configurations similar to 4G LTE radios. Therefore, Sub-6 radio topology could be similar to a C-RAN LTE fronthaul, in which dark fiber is used where available, and some form of multiplexing such as WDM or packet multiplexing is used where fiber is lacking.

Initially, the mmWave radios will be best-suited for high throughput applications such as fixed wireless access (FWA), while sub-6 radios will be best used for mobility.  In the long term, both radio types will be used for both use cases.

Since sub-6 radio coverage dynamics are similar to LTE, many CSPs will consider deploying sub-6 much like 4G LTE in a C-RAN to realize DU pooling efficiencies and offer higher performance using cell site aggregation.

Alternatives to a centralized pool of DUs, whether mmWave or Sub-6 radio, is an integrated DU and RU which eliminates the fronthaul transport and discrete fiber connections between the two.  This alternative expedites service delivery while reducing capital and operational expense, but also eliminates pooling and cell site aggregation capabilities.  Cell sites with integrated DUs will have midhaul, or what the IEEE refers to as fronthaul-II, in this section of the RAN transport.

Based on the various deployment options for mmWave and Sub-6 radios, either WDM based transport or a newer packet based transport using Time Sensitive Ethernet (TSN) will be used to pass 5G eCPRI/xRAN channels, as well as legacy 4G CPRI channels, from the cell site to a central aggregation point when an abundance of dedicated dark fiber is not available.

This blog is the second in a series about our vision for 5G transport. See part one here.

5G Transport: From Vision to Reality

Part one in a blog series about how Fujitsu is bringing the 5G vision to life

On the road to 5G, there are a number of different paths that communications service providers (CSPs) can choose. This blog is the first in a series about our vision for the 5G RAN, and how Fujitsu is working with leading CSPs to co-create these networks and bring 5G to life.

Transport is vital for building a robust and reliable network. The xHaul ecosystem consists of the backhaul, midhaul and fronthaul transport segments.  Dedicated dark fiber, WDM and packet technologies are used within these transport segments. As CSPs evolve their networks from 4G / LTE to 5G, there are several options explaining how those transport networks will be designed.

In a “Split Architecture,” the distribution unit (DU) connects to many macro site radio units (RUs) over multiple fronthaul fiber paths. This is a similar architecture to the 4G central RAN (C-RAN) where there is a central point; the DU in this case, fanning out to multiple macro sites for interconnect with the 5G radios, also known as RUs or Transmission Reception Points (TRPs).  This efficient technique is referred to as RAN Pooling, and along with cell site aggregation, offers mobile network operators the ability to engineer the RAN capacity based on clusters of sites coming into the central point DUs, instead of individual cell site demands.

The “Distributed DU” architecture involves DUs collocated with RUs at the cell site.  The distributed DU use case offers a latency sensitive architecture by eliminating the fronthaul transport path.  The fronthaul becomes a local connection between the top and bottom of the tower via fiber cable.  This is a low latency configuration, which also reduces costs by eliminating the fronthaul transport section.  The tradeoff is a loss of multi-site pooling and cell site aggregation with macro cell sites. Moreover, the midhaul capacity is reduced to 10GE rates.

Finally, there is the “Integrated DU” architecture, which integrates the DU into the RU at the cell site.  This architecture offers similar benefits as the Distributed DU use case, but with an additional advantage of lower CapEx and OpEx by combining these devices.   The combined DU and RU reduce the number of devices to install, manage and maintain resulting in expedited service turn-up and faster time to revenue.

To learn more, register for an archived webinar “New Transport Network Architectures for 5G RAN” with Fujitsu and Heavy Reading analyst Gabriel Brown: www.lightreading.com/webinar.asp?webinar_id=1227

Four Key Ingredients Solve Network Business Challenges

Network operators face seemingly conflicting challenges. They must maximize network assets, reduce costs, and introduce new revenue-generating services—all while maintaining existing legacy services. This may seem like an impossible combination to achieve, but just four key capabilities provide the right ingredients to reconcile apparently conflicting needs and profitably address these big business challenges:

  • Transport legacy services in groups. Individual legacy service instances are often transported separately, which makes inefficient use of network and fiber resources. It is more efficient to combine multiple instances into batches that can be transported together at higher bit rates.
  • Combine multiple services onto a single fiber. Fiber resources are expensive and constrained. Freeing up fiber capacity or reducing the number of leased fibers needed to sustain growing networks by transporting additional services over a single fiber pair saves on fiber resource costs.
  • Efficiently pack 100G wavelengths. Many 100G wavelengths are inefficiently utilized, cumulatively wasting a large amount of capacity. If more services can be transported over existing 100G wavelengths, the network is more efficient and additional costs can be avoided.
  • Provide transparent wholesale services. Services that support a range of SLA choices by allowing demarcation and providing visibility into traffic, management, and alarms are attractive to customers and a valuable source of revenue.

You may be surprised to find out that an often-overlooked technology, Optical Transport Network (OTN), provides all four of these capabilities. OTN is a standard (ITU-T G.709) digital wrapper technology that allows multiple services of various types to be packaged and transported together at higher rates. This universal package is ideal for transporting legacy services, which makes better use of network resources while simultaneously benefiting from modern technologies and rates. OTN also inherently allows an end customer access to network management and performance data. Finally, as networks move to 100G transport, OTN provides an easy means of filling partially utilized 100G wavelengths by transparently delivering a combination of services. Overall, OTN is a highly viable option that deserves serious consideration for network modernization. On grounds of both efficiency and ongoing revenue opportunities, OTN carries excellent potential for long-term ROI.

A Better Radio Access Network Delivers Performance and Savings That Can’t Be Ignored

The tried and true distributed radio access network (RAN) is the standard in mobile architectures. Significant improvements in performance—and reductions in capex and opex—would be required for service providers to consider making substantial changes.

But these are no ordinary times. The exploding popularity of digital video and social networking are driving wireless traffic relentlessly higher. In fact, a recent Cisco VNI study shows that worldwide mobile data traffic is growing at a 57% compound annual rate in the six-year period beginning in 2014.

What began as 2.5 exabytes per month two years ago will reach 24.3 exabytes per month before you know it.

Given this explosion in wireless traffic, C-RAN, the centralized radio access network, provides just the bonuses that make network upgrades a wise investment.

Evolving to a C-RAN architecture makes dollars and sense:

  • RAN performance can increase up to 30% through gains in spectral efficiency, cell site aggregation, and scalability.
  • Capex can be reduced up to 30% through savings in site acquisition, construction costs, and equipment efficiency.
  • Opex can be reduced up to 50% through savings in rent, power consumption, capacity management, and operation and maintenance.

“Mobile operators are increasingly seeking to deploy Cloud RAN architectures for efficiency and performance reasons,” said Gabriel Brown, senior analyst, Heavy Reading. “To disaggregate the radio access network into centralized baseband and distributed RF components requires a fronthaul solution that can meet stringent reliability, scalability, and opex targets.”

A new C-RAN solution from Fujitsu includes a smart WDM system with integrated diagnostics, remote visibility, self-healing functionality, and ultralow latency. The result is fast installation, high service availability, and a dense, scalable architecture that adapts easily to growing demand.

Learn more here.