Accelerating Network
Transformation

Disaggregated IP Routing and
Network Operating System (NOS)
IP WAVE: State-of-the-Art IP and Optical Networking

Disaggregated IP Routing and Network Operating System (NOS)

What’s Driving the Need for Disaggregation?
With the almost limitless access bandwidth offered by 5G and Fiber rollout, we are seeing consumers demanding
services with ever-increasing bandwidth. These services are becoming increasingly complex and often require service
performance guarantees such as guaranteed latency, bandwidth, availability, and so on. In addition, the majority ofservices are hosted in the cloud, and not only do these services evolve rapidly themselves, but the cloud model also
makes it relatively simple to introduce new services, if the network is able to support them.
So operators now find themselves in a dilemma, they need to keep network costs static or ideally reduce them when at
the same time the network needs to support new bandwidth-hungry applications and have the service agility to rapidly
introduce and support new services with ever more complex service performance guarantees. To make matters worse,
this dynamic service mix is making it increasingly difficult to forecast traffic patterns, demand, and capacity accurately,
they require a network that has the agility to rapidly adapt to changing demand, service mix, and consumer endpoints.
Traditionally, the IP/MPLS Wide Area Network (WAN) was been built from fully integrated routers, and this approach
was so successful that integrated routers providing IP/MPLS became ubiquitous for the WAN. But this integrated
approach lacks the agility and innovation velocity to meet the needs of today’s highly dynamic services and service mix
cost-effectively. With the tight coupling between the vendor hardware and software; if the routers are scaled for today’s
service forecasts, there is little or no ability to scale or adapt in the future without deploying additional hardware, or if
scaled for the future, the network has to be over-built at day 1, with no guarantee that the over-build will provide scale
where it is needed. In addition, with traffic, applications, and service complexity all surging, we see rapid advances in IP
routing capabilities and protocols, the tightly coupled routers we have today just don’t allow this innovation to be rapidly
introduced into a deployed network.
So network operators have become increasingly interested in disaggregation as a mechanism for increasing network
agility and controlling the TCO of their network.

The Promise of Disaggregation
The aim of disaggregation is to address a number of key objectives:

More
ChoiceAccelerated
Innovation
Velocity

Reduced
VendorLock-in
Key Objectives of NOS and Disaggregation

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Disaggregated IP Routing and Network Operating System (NOS)

Objective: Accelerated Innovation Velocity
Meets the service agility and scalability needs by allowing new hardware and software innovation to be rapidly
introduced to the network. Requires a common open disaggregated platform with a plug-n-play hardware and softwarearchitecture that supports the introduction of new hardware and software innovation into the deployed network. Thisapproach allows operators to select best-in-class components and upgrades are much quicker as they are based on theinnovation cycle of each component rather than on the whole platform, as is the case with a traditional monolithic router.
Objective: More Choice
A disaggregated routing approach enables network operators to select best-in-class hardware and software for theirown specific network and service needs. In terms of hardware, this allows a white box or NOS vendor hardware to be
selected that best meets the performance characteristics required for the given applications and architectures for which
it will be deployed. By definition, all of the hardware has to be carrier-class but characteristics such as number and typeof interfaces, capacity, size, airflow, redundancy, environmental hardening all vary or are configurable from hardware to
hardware. And when looking at the needs of specific architectures and applications functions such as synchronization,buffering, latency all need to be considered.
The software known as the Network Operating System (NOS) should be fully portable allowing it to operate on any NOS
certified hardware and merchant silicon. Moreover, it should provide fully open, standards-based northbound interfaces
allowing easy integration into any network orchestration system or ecosystem.
Going one step further, the software can use a containerized software architecture, with functional software blocks split
into their own software containers, this has a number of advantages in terms of choice. Firstly it accelerates innovation
velocity by allowing independence in the development, testing, and deployment of individual software components.
Secondly, by only running the essential NOS components, the NOS is able to run on hardware with very limited
specifications, increasing the hardware flexibility while keeping the same NOS. Thirdly software components can besourced from best-in-class software component vendors, not just from a single vendor, this is taking the SONiC approach
used in data centers and making it Telco-grade and applying it to the WAN.
Objective: Reduced Vendor Lock-In
With the traditional approach, the router hardware and software are fully integrated, so operators are locked into
this combination of hardware and software and their innovation time cycles for the duration of the router’s life in the
network. Disaggregation and the associated NOS open up both the hardware and software, for new hardware and NOS
components to be added to the network, so new innovation can be added from other vendors, without the need forforklift upgrades. In addition to accelerating the innovation velocity, breaking vendor lock-in will also allow more vendors
to compete, which will inevitably increase price competition.

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Disaggregated IP Routing and Network Operating System (NOS)

Objective: Lower TCO
All of the objectives described previously contribute to a disaggregated architecture with a containerized NOS allowing
an operator to reduce their TCO when compared with the traditional single-vendor integrated router:

More
ChoiceReducedNetwork
TCO

Accelerated
Innovation
Velocity

Reduced
VendorLock-in•More choice enabled by Disaggregation and an Open NOS
The same NOS can be used on integrated routers and/or ODM hardware in the same network
Enables the economies of scale which be gained from the use of standard hardware and software components
Allows selection of best-in-class components for optimal price-performance•

More choice enables right size scaling
Allows choice of “fit for purpose” software functionality with no over-engineering and only paying for		functionality when it is required
With a containerized NOS, only the required software components are used, meaning the hardware can be		scaled to support this functionality, it does not need to be scaled to support the whole NOS functionality•

Reduced vendor lock-in
Allows more competition.

•

Accelerating Network Innovation
Increasing the innovation velocity means that functionality that increases network efficiency and/or reduces		the cost per bit can be rapidly introduced to the network
Provides the ability to support new service types without the need to replace or add an overlay network if the		existing routers cannot support the functionality required

4 Application Note

Disaggregated IP Routing and Network Operating System (NOS)Why Now
As discussed previously, an increasingly complex service mix, with exponentially increasing capacity and complexity anddifficult to forecast demand is driving operators to look for a new approach that provides them with network agility theyrequire whilst controlling the TCO of their network. Disaggregation with NOS provides them with this.
Whilst a disaggregated approach has been common in data centers for many years now, the use cases and businessobjectives are not the same in WAN. In addition, there has been a lack of suitable ODM (Original Design Manufacturing)hardware suitable for the IP transport network, and the barrier to entry to creating a Network Operating System has
been high due to the quantity and complexity of the functional requirements. With virtual routers we saw the start of thisdisaggregation approach in the WAN, however, this only provided limited hardware disaggregation and was generally tied
to non-optimized white boxes with an X.86 chipset and was really only suitable for limited low complexity applications
such as vCPEs, firewalls, and route reflector.
However, more recently industry groups such as the Telecom Infra Project (TIP) and big operators like AT&T and
Telefonica have made major progress in showing the viability and applicability of disaggregation and NOS for the WAN.
On the back of this work, we now see the wide availability of ODM hardware suitable for the WAN, particularly the 1RU
white box range. At the same time, merchant silicon vendors such as Broadcom now have chipsets that meet the routing“speeds and feeds” required for even the most complex WAN applications. The software has also evolved with realtime Linux providing a powerful platform for network operating systems and ONIE providing an open environment for
installing a compliant NOS onto third-party white box hardware. With the predominance YANG data models and Netconf
interfaces we now also have a commonality in the data modeling and northbound interfaces, making it much morestraightforward to manage functionality from across the ecosystem.
So in answer to why now. Operators have the need for disaggregation and NOS and the technology is now available to
make it a reality in the WAN.

Disaggregation Approaches
Not all disaggregation approaches are the same, so when someone says they have a disaggregated router it can meandifferent approaches, so it is important to understand which approach they are talking about:••••

Network Function Virtualization
Hardware and Software Disaggregation
Hardware Disaggregation
Software Disaggregation

Each of these approaches is very different from the other with its own advantages and disadvantages. So it is worth
spending a little time understanding each approach.

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Disaggregated IP Routing and Network Operating System (NOS)

Network Function Virtualization
Although the approach does separate the software from the
hardware, it isn’t really about disaggregation at all, it is virtualization
and NFV. An example of the Network Functions Virtualization
approach is the Virtual Router, which was targeted at theEnterprise space.
In this approach, the virtual router is loaded with different functional
blocks running as their own virtual machines (VM) supporting
functionality such as route reflecting, NAT, firewalls being typical.
These “virtual” functions can be linked together with an approach
known as service chaining. Many of the leading router vendors suchas Cisco, Juniper, and Nokia today provide virtual routers based on
this NFV approach. These virtual router solutions generally use an
X.86 hardware platform with a hypervisor providing the hardware
abstraction and control of the virtual machines (VMs) on which therouter OS software runs.

VirtualVirtual Router
RouterManagement andOrchestration (MANO)

Control

Virtual
RouterSoftwareData Plane
Hypervisor
X86 Host
CPU

CPU

CPU

X86
ServerPlatform• Hardware-only disaggregated• Minimal stack with limited application— not easily extensible

This X.86 based virtual router approach provides high processing power for the control plane elements of the routerbut is limited in its I/O forwarding capacity, making it ideal for applications that fit these characteristics, such as routerreflectors, CPEs, firewalls, NAT. The virtual router has the additional drawback that the hardware is not really scalable inthe carrier WAN environment, where additional COREs can be added to X.86 boxes in the data center environment, thisis neither practical nor cost-effective in the carrier WAN.

RouterSoftware
Router Software
Network Operating
System (NOS)
Hardware Abstraction Layer
ONIEDisaggregation
Merchant Silicon
PlatformCPU

Router Hardware

From Vendor and/or ODM

6 Application Note

Hardware-Software Disaggregation
So to overcome these issues the first step to scalable,
open, disaggregation is to use white box hardware,
which could come from a range of ODM vendors basedon merchant silicon optimized for IP routing in the WAN
environment. This hardware is sometimes referred to as
the bare-metal switch, and with it we have hardware thatis suitable for the carrier WAN environment. Unfortunately,
it is not possible to just take any white box and load with
any NOS, additional software is required to open up thewhite box hardware to make it accessible to multiple
NOS vendors. The Open Network Install Environment(ONIE) has become a defacto standard for this software,
providing an open environment for installing a compliant
NOS onto third-party white box hardware. A hardware
abstraction layer is then required in the NOS to adapt it torun on the merchant silicon used in the white box.

Disaggregated IP Routing and Network Operating System (NOS)

So we now have hardware-software separation suitable for IP routing in the carrier WAN. This is a great first step, it
breaks the proprietary linkage between the router hardware and router software and we are already seeing a range of
ODM hardware vendors. However, today’s ODM hardware does not provide a full range of capabilities, architectures, andform factors, for example, some operators require fully redundant hardware others require modular platforms and we are
not seeing these capabilities from ODM vendors, yet.
However, with a disaggregated NOS, this is not a real problem. For the more complex hardware configurations suchas fully redundant or modular, the NOS can run on the vendor’s own hardware for configurations where certified ODM
hardware exists, the same NOS can run on this ODM hardware.
As ODM hardware evolves, providing more advanced merchant silicon, faster or cheaper hardware, fully redundant or
modular configurations these can be introduced into the network and the same NOS run over them as is already runningin the network.
This hardware-software disaggregation approach is able to meet the majority of the target goals set for disaggregation:•

More choice
The same NOS can be used on integrated routers and/or ODM hardware in the same network
Enables the economies of scale which be gained from the use of standard hardware and software		 components.
Allows selection of best-in-class ODM hardware for optimal price-performance•

Reduced vendor lock-in
Makes the process of adding new ODM hardware vendors and/or new NOS vendors to the network much		
simpler, no need for forklift upgrades•

Accelerating Network Innovation
Much simpler and quicker to deploy innovative new ODM hardware with the next generation of merchant silicon		
to the network
With the distributed cell site gateway DCSG) we are already seeing the first commercial deployments of this type ofdisaggregation.
Possible extensions to hardware-software disaggregation could be chassis disaggregation or disaggregation of
the software into containers. Whether you need these extensions and whether you want hardware or software
disaggregation, or both, depends where on the network you are targeting, and what you want to achieve.

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Disaggregated IP Routing and Network Operating System (NOS)

Hardware Disaggregation
This disaggregation approach is targeted at core routing or datacenter-like environments, and with a number of vendors, it is close tocommercial deployment.

Clustered
Clustered Approach
ApproachControl
Fabric Cards

With the old, integrated core router approach, to increase thecapacity of the network, you either had to over-specify the networkon day 1, deploying boxes with more capacity than was needed but
leaving capacity room for growth. Or you have to deploy new chassis
when growth occurs. The aim of chassis disaggregation is to provide
a much more cost-effective and graceful scaling of the network.
We are seeing a clustered hardware disaggregation approach toprovide the graceful scaling, in this approach the control plane
functionality is put into a control plane optimized white box such as
an X.86 server, and the data plane is split into white boxes dedicatedto providing the fabric and white boxes dedicated to providing theline card or packet forwarding capacities. Not only does this enables
graceful scaling, but it also allows the fabric capacity and the I/O
forwarding capacity to be scaled independently.

Data Plane
Cards

Control
Fabric• Focused on core routing• Complex• Doesn’t scale down

Whilst a very elegant and granular approach, it is by definition a multi-box approach that requires huge management
overhead. This type of approach is well suited to the core routing or data-center-like environments it is architected for,but realistically it cannot cost-effectively scale down to the access edge or aggregation regions of the network.

Software
Software Disaggregation
Disaggregation

Security

TimingTelemetry

L3 Services

L2 Services

NOS

Merchant Silicon

Router Hardware

From ODM and/or Vendor• Functionality as needed• Pay for what you use• Focused on the edge andaggregation networks

8 Application Note

Software Disaggregation
This disaggregation approach is targeted at access edge andaggregation parts of the network.
This is a future evolution of disaggregation and takes the hardwaresoftware disaggregation to the next level. In this approach, the NOS
itself is disaggregated into separate functional blocks, with eachof these functional blocks having its own container. This allows
operators to go to the software ecosystem to use best-in-classsoftware for each function. Or more likely in its initial phases, theNOS vendor incorporates new innovation and functionality from thesoftware ecosystem into their NOS, thereby increasing innovation
velocity. This approach allows the routers to be equipped with “fitfor purpose” NOS functionality with no over-engineering, operators
only paying for functionality when it is required. In addition, only
instantiating the required software components of the NOS for a given
application means the hardware can be scaled for its needs rather
than for the whole NOS.

Disaggregated IP Routing and Network Operating System (NOS)

Ribbons IP Wave rNOS Disaggregation Approach
Ribbon’s disaggregation approach is based on hardware-software disaggregation, with the Ribbon IP Wave rNOS being
able to operate on both Ribbon hardware and any certified ODM hardware using any certified merchant silicon vendor,
whether this is a 1RU platform targeted for the distributed cell site gateway (DCSG) or a redundant modular platform for
aggregation.

Ribbon IP Wave rNOS Evolution
Traditional Model

Disaggregation

Telco-grade NOS

Proven Neptune OS

IP Wave rNOSIP Wave rNOS Disaggregated(Telco SONiC)

Broadcom Silicon
Neptune Hardware

Broadcom Silicon
White Box Hardware:
ODM and/or Neptune

Any Vendor Silicon
White Box Hardware:
ODM and/or Neptune• Fully integrated router• Proven MPLS/routing OS• Open interfaces• Hardware-software disaggregation• NOS evolved from proven OS• Integrated and disaggregateddeployment options• Open interfaces• Integrated and disaggregateddeployment options• Software disaggregation• Telco grade SONiC

70,000+ Deployed

Available in 2022

Future Vision

With this approach, Ribbon is able to provide disaggregated routers optimized for the needs of the converged multiaccess edge and aggregation networks. Providing compelling, open, disaggregated solutions for:•••5G xhaul, including 5G Cell site Routers
Aggregation and Transport Networks
The Distributed Access Architecture used by Cable MSOs

With Ribbon’s disaggregation and NOS approach, operators, today, are able to realize a cost-optimized forecast tolerant
network that has the service agility and innovation velocity to evolve their network as rapidly as their needs evolve.
But it does not stop there - Future Vision
Ribbon is fully committed to a disaggregated future and we continue to innovate our IP routers in line with this vision.
Our IP Wave rNOS is architected such that it can be evolved into a telco-grade SONiC architecture, where we can use our
telco-grade rNOS functionality (high availability, MPLS, Telco VPN services, Telco control plane, etc), combined with bestinclass NOS components available from the open community. With this containerized software architecture, we will beable to take advantage of independence in the development and testing of NOS components, enabling CI/CD operationand increasing our innovation velocity.
Contact Us

9 Application Note

Contact us to learn more about Ribbon solutions.

About Ribbon
Ribbon Communications (Nasdaq: RBBN) delivers communications software, IP and optical networking
solutions to service providers, enterprises and critical infrastructure sectors globally. We engage deeply withour customers, helping them modernize their networks for improved competitive positioning and businessoutcomes in today’s smart, always-on and data-hungry world. Our innovative, end-to-end solutions portfoliodelivers unparalleled scale, performance, and agility, including core to edge software-centric solutions, cloudnative offers, leading-edge security and analytics tools, along with IP and optical networking solutions for 5G.
We maintain a keen focus on our commitments to Environmental, Social and Governance (ESG) matters,
offering an annual Sustainability Report to our stakeholders. To learn more about Ribbon visit rbbn.com.

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