Rapid Provisioning ofL1 Business Services
Obtaining a Competitive Advantage withAccess-to-Core OTN Switching

Layer 1 transport services are a highly profitable offering that Service Providers can sell to enterprises. These services,which include Ethernet, Fibre Channel, and legacy SDH/SONET, provide connection to data centers and other corporate
locations. However, it has always been a challenge to provision these services fast enough, due to the rigid, low-cost
nature of optical access networks.
Apollo delivers an innovative and economical access-to-core OTN switching solution that enables SPs to provision theselucrative services rapidly, speeding up time to revenues and maintaining customer satisfaction. SPs can also guarantee
service availability, by leveraging the dynamic restoration capabilities of end-to-end OTN switching.

Unique‘Access Optimized’
OTN Switching

Point-and-Click
ServiceProvisioning

ServiceAvailability
Guarantees

MuseTMSDN Provisioning

L1 Business Services• GbE 1/10/100• FC 1-32• SDH/SONET

Application Note

Access-to-CoreOTN Switching

Value-Added
Bandwidth-onDemandRapid Provisioning of L1 Business Services

OTN Transport vs. OTN Switching
The goal of optical networks is to transport services like Ethernet, Fibre Channel, and SDH/SONET over wide geographicareas. It accomplishes this by mapping services onto high-power colored wavelengths for wide-area transport, and bycombining colored wavelengths into single streams of light using DWDM.
OTN Transport• Transponders• Muxponders

Reconfigurableor FixedMultiplexers
Multi-Wavelength
DWDM Links

OTN
SwitchingService (Client) Interfaces

Colored Line (Network) Interfaces

•••
•

• 10G
• 100G• 200G – 600G in 50G increments

Ethernet (1GbE to 400GbE)
Fibre Channel (to FC32)
SDH/SONET
Misc VideoThe first step relies on the Optical Transport Network or OTN technology. This standard structure encapsulates one ormore services into different sizes of optical containers and adds bits for error correction and operational monitoring.
OTN then modulates the resulting bitstream of service payloads plus overhead onto a colored wavelength. In optical
networking systems, OTN technology is implemented in two practical ways:•OTN Transport: Transponders and muxponders map services directly onto wavelengths using an OTN mapper, in a•

OTN Switching: An OTN switch maps services

tightly coupled manner. Transponders map a single service onto a single wavelength (at essentially the same rate, forexample 100GbE maps onto a 100G wavelength), while muxponders combine and map several lower speed services
onto a single wavelength.

onto wavelengths – and interchanges services
among wavelengths – in a highly flexible
manner, via an OTN switching fabric. In theexample shown, a mixture of seven services
enter the node on gray wavelengths, and an
additional four services enter on coloredwavelengths via the ROADM. The OTN switch
combines all these service onto a single 400Gpurple wavelength. Note, that the diagramshows only a single direction of what inactuality is a bi-directional system.

10GbE110GbE210GbE3OTN
Switch100G100GFC8100GFC16400G

ROADM

100GbE2

10GbE4 10GbE5100GbE3

FC32100GbE110GbE1-5 FC1-3  100GbE1-3

OTN switching’s software-controllable flexibility brings multiple advantages for efficient wavelength use and dynamic
service provisioning. However, it is usually more expensive to implement than OTN transport, due to additional opticalelectrical-optical conversions and the cost of the switching matrices. Accordingly, OTN switching’s primary use has beenin the metro and core where economies of scale weigh in its favor. In this application note, we show how to extend OTN
switching economically to the access network.

2 Application Note

Rapid Provisioning of L1 Business Services

Baseline Approach Using OTN Transport
In a pure OTN transport approach, L1 business services (such as 1/10 Gigabit Ethernet, Fibre Channel for storage area
networking, or legacy SDH/SONET) originate as gray wavelengths, are mapped onto transponders or muxponders, andthen routed across the network using ROADMs.
L1
L1BusinessBusinessServices
Services•• 1/10
GbEGbE
1/10•• 1-32
FC
FC 1-32•• SDH/SONET
SDH/SONET

TRP/
MUXP

OTN
TR

OTN
TR

TRP/
MUXP

Access

OTN
TR

TRP/
MUXP

OTN
TR

TRP/
MUXP

OTN
TR

OTN
TR

Metro

OTN
TR
OTN
TR

Access

OTN
TR

OTN
TR

OTN
TR

OTN
TR

TRP/
MUXP

OTN
TR

TRP/
MUXP

Core

In most cases, this baseline approach requires the addition of new wavelengths across the network for each new service.
This has many downsides. End-to-end optical engineering for each new service adds operational expense, and unlessthe muxponders are already strategically located, new transport cards are needed, adding capital costs. This approach isvery wasteful on wavelengths, creating high congestion in the metro and core. It requires a manual de-mux and re-mux ofwavelengths as the only way to consolidate multiple services onto fewer wavelengths. Perhaps the largest drawback is along provisioning cycle, which delays revenues and contributes to customer dissatisfaction.

Applying OTN Switching to Streamline the Metro and Core
Replacing OTN transport entities with OTN switches at key traffic exchange points in the metro and core, begins to address someof the limitations of the baseline approach. As previously stated, this has been the primary application of OTN switching to date, as
its added benefits apply to many services and wavelengths, outweighing added costs. These benefits include:

L1 Business Services• GbE 1/10
• FC 1-32• SDH/SONET

TRP/
MUXP

TRP/
MUXP
TRP/
MUXP

TRP/
MUXPOTNTR

OTN
TR

Access

OTN
TR
OTN
TR

OTN
TR

Access

OTN
TR

Metro
OTN
SW

100G-200G
Metro
OTN
SW

Core
OTN
SW

OTN
TR

OTN
TR

Core
OTN
SW

200G-400G
Core
OTN
SW

•Functional separation: Enables the use of transmission technologies in different parts of the network (i.e. access,metro, core) that are best suited to each part’s unique topology and performance requirements. Moreover, thesetechnologies can be deployed independently, evolving at their own pace.

•Grooming: All it takes is a few clicks to aggregate multiple lower-speed links into a smaller number of higher-speed
links, ensuring no wasted bandwidth and providing a solution at a lower overall cost. Studies indicate that wavelengthsavings are on the order of 35%.

3 Application Note

Rapid Provisioning of L1 Business Services•

All-optical bypass traffic: OTN switches operate seamlessly with ROADMs. Any wavelengths carrying services•

Dynamic restoration: In case of link failures, OTN switches can re-route individual services on other working

that are not dropped or groomed at a node can be “passed through” by the ROADM, entirely within the optical domain,
reducing the number of interfaces on the OTN switch.
wavelengths. This can work in conjunction with ROADMs, to provide wavelength-level restoration and deliver thehighest level of network robustness and service availability.

Yet, even with all these benefits, deploying OTN switches in the metro and core still does not solve the end-to-end L1
business service-provisioning challenge. To address this, we must find a way to extend OTN switching economically tothe access networks.

Extending OTN Switching to the Access
Until now, engineering of optical access networks was focused on low cost. Transponders or muxponders map theservices at a node onto individual 1G or 10G colored wavelengths. These wavelengths are then inserted manually intoa WDM stream on the access ring using 2-degree fixed optical add-drop multiplexers (F-OADMs). This is a rigid process
whereby every service requires design, the WDM ring requires amplification and dispersion compensation, and changes
and responses to customer requests take too much time.

TRP/
MUXP

TRP/
MUXP
2-degree
FOADM

Multiple 10G
WDM Wavelengths

2-degreeFOADM
TRP/
MUXP

2-degreeFOADM

2-degree
FOADM
TRP/
MUXP

2-degree
FOADM
TRP/
MUXP

FOADM NodeCollector
Node2-degree To Core Network
FOADM

TRP/
MUXP

All the services on thering are mapped onto asingle DWDM

However, a new generation of economical Small Form Factor OTN switches, like the Apollo 9901X, is starting to change
the equation, particularly for Layer 1 business services. These enable the ring to use a single 100G wavelength ratherthan a WDM fiber. Services connect to the OTN switches via low-cost gray interfaces, and are added to the ring traffic
under software control.

AccessOTN Switch
AccessOTN Switch

AccessOTN Switch

Single 100G
Wavelength

AccessOTN Switch

4 Application NoteAccessOTN SwitchCollector
NodeTo Core NetworkAccessOTN Switch

All the services on thering are mapped onto
a single wavelength

Access OTN Switch
100GLine
I/F

Line
I/F

Service Interfaces

Line interfaces move frommuxponders into the switch

Rapid Provisioning of L1 Business Services

This produces a flexible optical edge at the same cost as the traditional approach, with many benefits, including:•One-time network engineering: A single wavelength for the access ring is engineered once, rather than•

Fast service provisioning: Services physically plug into the OTN switches via simple gray wavelengths, and are•Easy changes: Ongoing moves, changes, additions, and deletions of L1 services on the optical network are all•

Value-added services: By selecting appropriate features on the OTN switch service interfaces, Service Providers•

Advanced protection schemes: Various levels of service availability guarantees can be extended to businessengineering multiple wavelengths separately for each node.

provisioned with a few clicks. No additional network engineering is required. By working in conjunction with OTN
switching in the metro and core, software-controlled end-to-end provisioning is made possible.

software-controlled.

can offer value- added services to their business customers, like L1 optical encryption and bandwidth-on-demand.

customers, by using different combinations of redundant links and dynamic service restoration via OTN switching.

MuseTMSDN Provisioning

L1 Business Services• GbE 1/10
• FC 1-32• SDH/SONETOTNTRAccessOTN SW100GAccessOTN SW
OTN
TRAccessOTN SW

100G

Metro
OTN
SW

100G-200G
Metro
OTN
SW

AccessOTN SW

Core
OTN
SW

OTN
TR
Core
OTN
SW

OTN
TR

200G400G
Core
OTN
SW

Apollo Access-to-Core OTN Switching Solution
The Apollo 9900 family of OTN switches makes it easy to deploy and obtain the full value from OTN switching solutions,especially rapid provisioning of L1 business services. Apollo 9900 works together with Apollo 9600 transport elements,
including transponders, muxponders, and CDC-F ROADMs, for powerful and customized optical networking solutions. Muse
lifecycle automation applications deliver speedy service provisioning, predictive maintenance, and dynamic restoration.
Moreover, Apollo 9900 OTN switching has many distinctive capabilities:•Access-to-Core coverage: Supplies the ‘right-sized’ switch for economical deployment anywhere in the network,•

Complete set of Layer 1 service interfaces: Aggregates and grooms all major types of service traffic, including•

Integrated Layer 2 interfaces: Transports MEF-compliant Ethernet packet services over the OTN domain tofrom the access to the core. In particular, the family now premiers an innovative 9901X ‘access optimized’ OTN switch.
Ethernet (1GbE, 10GbE, 40GbE, 100GbE), Fibre Channel (FC1- FC32), and SDH/SONET.

connect routers, with interface bandwidth provisioned dynamically, via ODUflex.

5 Application Note

Rapid Provisioning of L1 Business Services•

Full Switching Matrix Availability: Makes the full capacity of each OTN switch available for all L1 and L2 services,•Evolvable line interfaces: Uses a pluggables strategy to always support the most recent line interface technologies,•surpassing some competitors that have limits for different configurations.
including 400GZR/ZR+.

Open Control Interfaces: Allows customers to exercise control through 3rd-party optical domain controllers, via
standard Netconf/Yang northbound interfaces, as defined by the OpenROADM MSA.
••••

Medium-capacity core
5.6T capacity (scalable to 14T)

Pay-as-You-Grow Metro
2.8T Capacity

••

9914

9904X
9901X

••
•

Access Optimized
1U
400G Capacity

9901X

100G
9901X

9904X

to 400G
9904X

High-capacity core
16T (scalable to 32T)

9914

to400G

9932

9914

Summary
In the past, the OTN switching business case has been primarily in metro and core networks, where it could maximize
benefits across a large number of services and wavelengths. Apollo now extends OTN switching to access networks,
enabling end-to-end applications including rapid provisioning of Layer 1 business services.

About Ribbon
Ribbon Communications (Nasdaq: RBBN) delivers communications software, IP and optical networking solutions toservice providers, enterprises and critical infrastructure sectors globally. We engage deeply with our customers, helping
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visit rbbn.com.

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6 Application Note