Key challenges of service providers
The service providers are facing multiple technical and business challenges which needs to be
considered while drafting the strategic solution. Some of the key challenges, which every service
provider would want to solve are:
• How to deal with bandwidth explosion
with increasing bit-rate and latencysensitive data consumption?
• How can cost of last-mile connectivity be
• How to design and deploy integrated
infrastructure for last mile connectivity
including PON and Mobile RAN?
• How to effectively monetise
the last-mile assets?
• How to seamlessly scale the last-mile
performance and bandwidth with
increasing subscriber base?
• How to address the front-haul challenges
such as latency and synchronisation?
• How to minimise subscriber churn by
enhancing the quality of experience with
real time network performance monitoring?
Increasing need for
Virtualise Access Network for a Software-defined Future
Telecom industry is going through a massive disruption both in terms of technology and also the
way they look at their TCO models. While the TCO reduction always remains as one of the key
objectives, service providers are realising that the programmable, open and disaggregated multiaccess network helps them map their business requirements faster with their technical roadmap.
The first step for this is to re-architect the service provider’s central office through the
disaggregation of hardware from software layer. The hardware abstraction layer with the profiles
per subscriber along with SDN controller and open APIs will lead to following benefits:
• Clear delineation of control and data
planes, wherein the control plane
becomes an app on the SDN controller
and the data plane gets offloaded on the
RAN or OLT/switch hardware
• Software abstraction increases the agility
thereby ensuring faster roll out of
• Flexible architecture deployment by
creating mini central offices for MEC/OLT
placements along with edge caching for
enhancing the user experience
• Add and scale BNG software functions for
wired access and EPC for wireless access
Key challenges of service providers
Programmable, open &
disaggregated infrastructure at
access layer – Need of the hour
Increasing need for disruptive solution
The next-gen Passive Optical Network (PON) could function as the access backbone for any
other last mile technology. The hardware MAC functions (OLT MAC) connect to the hardware
abstraction layer (VOLTHA) which controls and manages the OLT and ONU hardware. VOLTHA
retains the service provider’s profiles and helps the SDN controller manage this abstraction layer
over an open API viz. open config or gRPC.
Programmable, open & disaggregated infrastructure at access layer – Need of the hour
The SDN controller hosts control plane functions (like vONU and vOLT) and this architecture helps
in clear delineation of software and hardware layer. This controller can either be placed in a central
office or a data centre and can have the white box hardware OLT and ONU located near the
subscriber as per the optical distribution profile.
As this programmable and open infrastructure is extended till the last mile, the next step is to
prepare for wireless technologies like 5G and ongoing capacity augmentation for 4G/LTE. With
fibre available till the last mile, the network becomes ready for subsequent densification for 5G
Transition towards software-defined network
Both 4G and 5G require significant front-haul architecture upgrade. These are primarily linked to
latency (RTD `200 usec from RRH to BBU excluding processing time), frequency (16ppb/50ppb),
phase (+/- 1.5 to 5 usec) and bandwidth requirements for front-haul. With cloud RAN architecture,
the BBU clusters and DU can be moved to the cloud or data centre, and latency, frequency, phase
and bandwidth have to be considered for the solution to work. The provisioning of dark fibre or
having next-generation programmable PON can address 4G and 5G front-haul requirements and
enable roll-out readiness.
STL’s Programmable FTTx
pFTTx Technical Architecture
With vEPC, vBBU, vOLT, vONU and vBNG becoming software-defined; the control functions
of these components are on the SDN controller. The forwarding on the switch fabric with the
Programmable APIs viz. Netconf, gRPC, REST, P4 to program the FPGA or the chip silicon in the
forwarding plane, while the switch fabric would be deployed over central offices or at the regional
Business benefits of pFTTx
The implementation can further be extended to the transport domain with a programmable
transport with DWDM (Metro and Long-haul) and MPLS using the software underlay network. The
secure SD-WAN can be used for running application and can be initiated right from the uCPE and
RAN nodes for better quality of experience, while continuing with the software-defined access
backbone. Also with traffic encryption and secure tunnelling, SD-WAN can ensure that the traffic is
well protected and it maximises the networking capabilities offered by the underlying layers.
pFTTx – Way forward for Gigabit broadband
STL’s Programmable FTTx
About Sterlite Technologies Ltd
Sterlite Technologies Limited (STL), a global leader in end-to-end data network solutions, is
developing Programmable, Open and Disaggregated Solutions (PODS). With Programmable FTTx
(pFTTx) and Programmable Radio (pRadio), we are addressing the key challenges of the service
providers, while leveraging the ONF specifications like SEBA, Trellis and COMAC.
STL gives major focus on such cutting-edge virtualised and software-defined access in its
production environment, while transforming its existing FTTx network to a Programmable FTTx
network. The key principles of disaggregation, overlay, and chaining have helped in architecting
the subsequent steps for modernisation of central offices, while integrating with the legacy GPON,
legacy transport and with existing space, power and environmental requirements of central offices