We discuss the following topics in this blog:
- Why is the Impact of Fibre Networks Limited?
- Linear Architecture of BharatNet.
- Fiber Point of Interconnect (FPOI) and Associated Operational Challenges
- Use of GPON Technology
In addition to these topics, we shall also be answering the following FAQs:
- What is WiFi?
- What is an Optical Fibre Cable?
Why is the Impact of Fibre Networks Limited?
The government of India recently announced that more than 120000 Gram Panchayats out of 250000 have been connected through an optical fibre (OF) network. In this process, approximately 2.5 Lakh kms of optical fibre has been laid, which is expected to usher a new era of digital revolution in Rural India.
However, it is strange that despite the creation of such a huge fibre network in remote rural areas, there are no serious takers and the impact remains limited. Telcos face a challenge in terms of upgrading their backhaul to fibre and without that, digital evolution in villages seems a far cry.
Looking at the way Phase 1 of BharatNet project has been implemented, following are the reasons that can be attributed for the lukewarm impact of the NOFN project.
1. Linear Architecture
Under Phase 1 deployment of Bharatnet, the network has been designed using linear architecture. The endpoint connectivity at the gram panchayat (GP) location has only a single fibre path available, from the nearest exchange. Due to lack of a backup path, the GP location gets isolated in case of any fault. Typically, route length between GP and nearest exchange varies from 5 Km to around 20 Km and probability of isolation increases with the length of the route. Hence achieving uptime of more than 99% (This is a basic requirement of any commercial grade network) becomes very difficult on such networks.
2. Fiber Point of Interconnect (FPOI) and Associated Operational Challenges
During the first phase of deployment, existing fibre laid by BSNL and other PSUs was leveraged to connect the GP with the nearest exchange. In order to reach the GP, maximum possible length was utilized from existing laid fibre for interconnecting exchanges and only incremental fibre route was created as the last mile to reach the GP. In this process Fiber POI was created to tap existing fibre with the last mile. However, this design has created serious operational challenges which affect timely fault localization and restoration, hence uptime.
3. Non-availability of end to end spare fibre for leasing purpose
Normally Communications Service Providers(CSPs) prefer dark fibre leasing for creating reach to distant locations. However, in the first phase, since existing legacy OF cable of PSUs laid in past had been tapped already, this was not a possibility. Now that end to end fibre is owned by two entities (Telecom PSU and BBNL), IRU (Indefeasible Right to Use) agreement for fibre leasing also becomes complicated and end to end accountability in case of SLA issues also becomes vague.
4. Use of GPON Technology
In case of non-availability of dark fibre for leasing, CSPs may choose to opt for bandwidth leasing. In order to have bandwidth leasing option in place, CSPs will need to interface with BBNL infrastructure on select active POI, to carry bandwidth from POI location till the bandwidth drop point. However, the technology to support active POI requires L3 routing functionality so that two diverse networks can be interfaced with proper demarcation. In the case of Bharatnet deployment, GPON has been chosen as the technology which is considered as an access technology. Hence creating POI with GPON OLT is operationally not feasible due to operational requirements of managing demarcation points. Hence active bandwidth leasing is also not feasible in the current form of deployment.
5. Capex prohibitive for potential users
The exchanges for GP aggregation are also located away from city or major locations where CSPs have fibre presence. Assuming that challenges highlighted in the points mentioned above are addressed, the problem of connecting PSU exchange location with tapping points of CSP still remains. In most of the cases, the requirement of tapping CSP fibre with PSU exchange will increase the capex requirement multifold. Hence it may become cost prohibitive to either lease fibre or bandwidth from Bharatnet infrastructure. From the intent highlighted by the government on various forums, it comes out clearly that fibre infrastructure created with Bharatnet project will be used for enabling digital services to rural areas. To make this intent a reality, It’s imperative that the Government should start acting immediately to upgrade ph-1 infrastructure to make it carrier-grade and future ready.
What is WiFi?
Put simply, WiFi is a technology that uses radio waves to create a wireless network through which devices like mobile phones, computers, printers, etc., connect to the internet. A wireless router is needed to establish a WiFi hotspot that people in its vicinity may use to access internet services. You’re sure to have encountered such a WiFi hotspot in houses, offices, restaurants, etc.
To get a little more technical, WiFi works by enabling a Wireless Local Area Network or WLAN that allows devices connected to it to exchange signals with the internet via a router. The frequencies of these signals are either 2.4 GHz or 5 GHz bandwidths. These frequencies are much higher than those transmitted to or by radios, mobile phones, and televisions since WiFi signals need to carry significantly higher amounts of data. The networking standards are variants of 802.11, of which there are several (802.11a, 802.11b, 801.11g, etc.).
What is an Optical Fibre Cable?
An optical fibre cable is a cable type that has a few to hundreds of optical fibres bundled together within a protective plastic coating. They help carry digital data in the form of light pulses across large distances at faster speeds. For this, they need to be installed or deployed either underground or aerially. Standalone fibres cannot be buried or hanged so fibres are bunched together as cables for the transmission of data.
This is done to protect the fibre from stress, moisture, temperature changes and other externalities. There are three main components of a optical fibre cable, core (It carries the light and is made of pure silicon dioxide (SiO2) with dopants such as germania, phosphorous pentoxide, or alumina to raise the refractive index; Typical glass cores range from as small as 3.7um up to 200um), Cladding (Cladding surrounds the core and has a lower refractive index than the core, it is also made from the same material as the core; 1% refractive index difference is maintained between the core and cladding; Two commonly used diameters are 125µm and 140µm) and Coating (Protective layer that absorbs shocks, physical damage and moisture; The outside diameter of the coating is typically either 250µm or 500µm; Commonly used material for coatings are acrylate,Silicone, carbon, and polyimide).
An optical fibre cable is made up of the following components: Optical fibres – ranging from one to many. Buffer tubes (with different settings), for protection and cushioning of the fibre. Water protection in the tubes – wet or dry. A central strength member (CSM) is the backbone of all cables. Armoured tapes for stranding to bunch the buffer tubes and strength members together. Sheathing or final covering to provide further protection.
The five main reasons that make this technology innovation disruptive are fast communication speed, infinite bandwidth & capacity, low interference, high tensile strength and secure communication. The major usescases of optical fibre cables include intenet connectivity, computer networking, surgery & dentistry, automotive industry, telephony, lighting & decorations, mechanical inspections, cable television, military applications and space.