This blog aims to make the respective clarifications against some myths that are generated around Passive Optical LAN (POL) technology, often caused by a reduced technical knowledge of the technology when compared to legacy or traditional (point-to-point) technologies that exist in the telecommunications infrastructure market.
POL has been successfully implemented in verticals such as Hospitals, Airports, Corporate Buildings, Industry, Education sector among others giving a high level of robustness and experience for the end-users of the mentioned verticals. These experiences can be perfectly validated with real users who have opted for POL technology.
The intelligence that is handled in a POL system is summarized below.
- Reduction of Network Latency
- Centralized administration generating greater flexibility in the allocation of network services
- Physical and logical separation of the Network
- Allows the implementation of redundancy and high availability schemes
- Efficient allocation and management of bandwidths avoiding unnecessary oversizing
- POL technologies comply with Telecommunications infrastructure standards that are recognized in the market as ANSI / TIA 568.0-D, ANSI / TIA 606C, technology approved by BICSI through its Telecommunications Distribution Methods Manual (TDMM) chapter 5 for application of large layer 2 networks and with layer 3 functionalities.
- It handles high levels of encryption such as AES 128 and authentication protocol based on IEEE 802.1X, RADIUS, TACACS), Quality of service QoS (Traffic Prioritization Levels) distributed in the passive optical network to attend priority to the applications over IP protocol that should require (Images, audio, real-time communications, VoIP, video conferencing).
- In addition to converging IP technologies, POL systems can integrate signals of a similar nature such as CATV and handle similar communication devices such as conventional telephones in the same infrastructure. HIGH LEVEL OF CONVERGENCE.
- Allows dynamic device discovery.
- It allows the integration of globally recognized administration tools (NMS) since they work standard protocols type SNMP.
- Use of single mode fiber optic as a means of transmission in a large part of the infrastructure and connection of copper to user devices, but with the great difference that the copper component is considerably reduced.
MYTHS AND FACTS EXPLAINED
MYTH: The network is purely passive. There are no smart devices that handle collisions and traffic on the network without allowing communication of the devices horizontally. It only allows vertical communication.
FACT: In POL systems the upload traffic, for example between the ONT and the OLT, handles a mechanism called TDMA generating a collision-free environment. Finally, in a traditional gigabit solution, traffic from lower layer switches will be transmitted to higher layers generating more latency in the network. In GPON systems, intelligence will not only depend on the Core equipment but can also be managed from the OLT and ONTs where they have Layer 2 and 3 functionalities.
MYTH: Physical separation is not allowed and increases logical segregation of the network.
FACT: POL systems allow the physical and logical separation of the network perfectly through VLAN schemes at Layer 2 level as segmentation of broadcast domains in Layer 3 through routing protocols. The physical separation can also be established at the hardware level if desired.
MYTH: Each Splitter and each ONT can become a point of failure. The redundancy between the devices and communications would be done with double OLTs and multiple splitters, which makes the administration exhausting and increases costs.
FACT: It is clarified that splitters are passive elements and are not subject to failure because they do not require power sources. POL systems can be configured for high availability through redundancy schemes, switches also require duplicating equipment, boxes, ports, power supplies, among others.
MYTH: It is not a familiar transmission medium for LAN networks.
FACT: Optical systems, on the contrary, are very familiar in LAN environments, since several years ago they are used for backbone and intercampus distributions.
MYTH: The new generation of PoE Remote Powering (60-90 Watts new generation for smart buildings and IoT) is not supported by POL.
FACT: POL technologies have conceptualized PoE ++ support through the ONTs that connect the end user devices that need to be powered with 60 and 100W levels.
MYTH: There are no smart devices that allow any device on the network to be connected to any point on the network.
FACT: On the contrary, POL networks have intelligent equipment such as the OLT and ONT where the latter allows the connection of any IP device of the user network or networking if desired.
MYTH: Security. Levels of encryption, priorities and customer service queues are managed only by the Core to provide priority attention to the applications that require it (e.g. images, audio, real-time communications such as VoIP, Video conferencing), application monitoring. Encryption is handled from OLT-ONT, but not from ONT-OLT due to the nature of the PON broadcast. How do you handle the security level where all the ONTs see the signals that the OLTs transmit?
FACT: Passive optical network technologies handle high levels of security for the following aspects:
1. On a physical level: The optical fiber is immune to the electromagnetic fields that are generated in the medium avoiding some theft of information by non-direct mechanisms on the transmission medium. Additionally, it is not possible to capture information directly affecting the physical environment as it happens in the metallic medium of balanced trailing torque.
2. Logically: GPON systems handle natively and by default AES 128 encryption avoiding capturing information especially in downstream traffic. Additionally, GPON systems handle all the typical Ethernet protocols and functionalities such as Access Control Lists (ACL), 802.1X Port Security, whereas traditional network systems require more specialized switches and other ranges to implement. security policies, for example the MACsec functionality that must be configured and that are not supported by other ranges of switches from the same manufacturer or with legacy equipment.
It is true that GPON systems handle encryption in downstream through AES 128, but we must remember what was stated in reality number 2, where GPON networks handle the same security protocols of a switched network such as 802.1 X port security, Access control lists, authentications that work both ways additionally in an Ethernet network, an attacker can use a media conversion device to enter the switched network instead in GPON, copying an ONT is too difficult in addition to these must be synchronized and be detected by the OLT through a unique identification number (serial number).
In addition, AES 128 encryption in GPON systems is enabled by default instead in conventional switch systems, they must use trustsec Mac sec 802.1AE with AES 128 encryption in New devices, not compatible with previous references to protect the eavesdropping effect in communications , also in the complexity in its configuration that requires expert personnel. As for upstream traffic, the risk is not as high as the trunk ports of a traditional switch since it has implemented security countermeasures in the access port, in addition to the TDMA-based Uplink transmission mode makes it more difficult to obtain Upload traffic information using typical hardware that handles 802.3 Ethernet. There is evidence that through a sniffer you can perfectly hear the traffic that passes in a given Vlan in a traditional scheme, in GPON solution it is evident that you cannot register network management traffic or Switching protocols, to be more specific, no network communication is recorded between the OLT and ONT. Nor should we forget the advantages of the physical means of intervening directly or indirectly on the optical link.
MYTH: There is no dynamic discovery of devices.
FACT: On the contrary, it is claimed that there is dynamic discovery, the GPON system allows you to discover all the ONT of the system and networking devices. Additionally, it supports LLDP-Med which is equivalent to some proprietary discovery protocols.
MYTH: Weak in troubleshooting tools and circuit tracking.
FACT: It is clarified that in any optical system, there are verification tools for troubleshooting and circuit tracking using a Power meter, VFL (Visual Fault Locator) and even an OTDR device, therefore the statement does not apply.
MYTH: To give a speed of 1 / 10Gbps you would have to place a fiber directly to the user and use an active network in structured cabling, direct connections can damage the ports of the equipment in PON technologies.
FACT: POL systems adequately handle the concept of Power Budget to ensure the levels of optical power to be transmitted. In these systems, the physical projects have attenuations of the optical dividers to guarantee the optical dynamic range in the transmission to the access equipment, which in this case are the ONT.
MYTH: Difficult procurement of personnel who know the technology for easy administration.
FACT: Today there are training programs in this type of technologies for the implementing channels. There is a network of highly trained and certified channels. In the case of most manufacturers, knowledge is transmitted not only to the channel but also to the final customer for system administration and management. The configuration interface through CLI is like switch vendors structure so a networking engineer can adapt perfectly to POL systems.
MYTH: There is no compatibility between the different brands of POL networks. It does not offer interoperability between equipment / brands.
FACT: Regarding the interoperability issues of POL equipment. The technology is based on compliance with international standards (ITU-T G.984, ITU-T G.987, ITU-T G.988, ITU.T G.989). The standards left open some sections for each manufacturer to carry out its development. Currently, interoperability at the OLT and ONT level is only guaranteed with equipment of the same brand, but there are already industry efforts in this regard. The only thing that can be highlighted at this point is that when handling a single-brand solution, it will generate the following benefits rather than disadvantages such as:
- Elimination of gray areas of responsibility in the implementation of a LAN network project. There is only one person responsible in case of failures of any component, whether active or passive, of the solution.
- Support of Manufacturers.
- Complete training of the solution at active and passive level from design to implementation and subsequent administration of the system.
- Local and remote support.
- Extended warranty programs of up to 25 years.
MYTH: PON uses the TDMA (Time Division Multiple Access) communication scheme accessing each OLT every 125 microseconds vs. 2Tbps or greater of the capacity of the switches.
FACT: TDMA is used for UPSTREAM communication between ONT and OLT. The TDMA scheme allows each ONT to use a fixed or variable time interval that scans the entire bandwidth of the channel. The available bandwidth for each ONT can be set according to need, which is checked periodically or according to service contracts. Therefore, the switching capacity is not compared with GPON TDMA communication. OLTs also have very high switching capabilities and are often superior to switches.
MYTH: POL versions are not supported by international standards ISO 11801 or ANSI / TIA-568-1.D, Commercial Building Telecommunications Cabling Standard, ANSI / TIA-568-2.D, Commercial Building Telecommunications Cabling Standard; Part 2: Balanced Twisted Pair Cabling Components, ANSI / TIA-568-3.D, Optical Fiber Cabling Components Standard.
FACT: POL perfectly complies with the structured cabling standard especially those mentioned. On the contrary, of course, structured cabling standards are complied with and are endorsed by ANSI / TIA 568.0-D as well as by BICSI through the telecommunications methods manual (TDMM version 13) where it is established that:
- The ANSI / TIA 568.0-D establishes a chapter in table number 8 where they describe all the applications that can run in a structured cabling network, the acceptance of the EPON and GPON protocols is clearly evidenced according to the extract obtained from the mentioned standard as seen below:
- It is verified at Annex A of the ANSI / TIA 568.0-D standard, where there is talk of a centralized fiber topology, that the optical elements in the ODN must be properly selected to comply with this topology as evidenced in the following picture:
- BICSI compliance and acceptance of POL or POL technology can also be verified through TDMM in Chapter 15, also indicating topology as the optical attenuation levels to be guaranteed.
MYTH: Automated physical infrastructure management systems AIM (ANSI / TIA 606C, ISO / IEC 14762-2-1, ISO / IEC 18598) are not available in PON-LAN architectures.
FACT: AIM systems are usually focused on datacenters markets where high cable density levels are required to be managed following ITIL guidelines. There must be clear procedures to take full advantage of these solutions, it has been shown that many customers underutilize these types of solutions and finally do not end up using them since they do not have strict management procedures. Additionally, GPON systems handle a protocol called OMCI that allows monitoring and properly managing the elements that make up the system.
MYTH: Fiber optic measurements for PON networks are much more demanding compared to a point-to-point architecture. Standard power meters are not accurate enough in the values of the downstream channel, in addition to reference the test in the upstream channel the ONT must be in contact with the OLT, which means that the service will be interrupted.
FACT: On the contrary, the instrumentation used in GPON systems is simple and inexpensive. Power meters are easy-to-use equipment unlike copper meter systems that must analyze many parameters to ensure their transmission due to their susceptibility to intrinsic or exogenous crosstalk or noise that occurs in the metallic environment. The optical tests are carried out in the passive channel and the active part does not necessarily have to be connected, in conclusion, if the levels of insertion loss of the optical channel are guaranteed at the appropriate levels, the active part will work without problem.
MYTH: PON network measurement equipment is more expensive.
FACT: Regarding the measuring equipment in POL, there are a variety of equipment and manufacturers in the market with competitive prices, traditional systems also handle fiber and copper links, so they must make a large investment of network certification equipment.
MYTH: Each ONT team must have levels of individual encryption, authentication, quality of service, added to the configuration parameters of each of the services of the building devices, which would increase the cost of these solutions. You should establish a strategy or consult beforehand about the software that facilitates the administrator and implementer the creation, support and traceability of the templates of the profiles of each device which represents an important challenge for the administrators of this type of platforms.
FACT: ONT equipment is an intelligent equipment that is capable of effectively handling QoS, VLAN Assignment, bandwidth control both in the rise and in the descent but one of the most important features and of great advantage compared to traditional systems, is these devices are very low management, that is, their configuration is done centrally from the OLT through the user profile concept that several templates can be implemented and then the ONTs can be provisioned easily and quickly, in addition They have administration software with a user-friendly graphical interface for ease so the challenge is already solved. The costs remain quite competitive if we compare it with the active equipment of a traditional network.
MYTH: The ONTs will be in the work or coverage areas towards the device. Control, inspection and surveillance mechanisms must be established within a project risk matrix since the ONT is vulnerable and may be replaced or otherwise stolen (the ONTs are expensive equipment).
FACT: Regarding the location and positioning scheme of the ONTs, there are several methodologies for its final installation depending on the needs of the user and the levels of restriction required. Something that we want to highlight is that an ONT is worth less than a laptop or an IP phone, which are more desirable devices for theft.
MYTH: POL does not contemplate the use of standards such as BICSI 005 (Electronic Safety and Security (ESS). System Design and Implementation Best Practices) and BICSI 007 (Information Communication Technology Design and Implementation Practices for Intelligent Buildings and Premises) that have signed a connection method that eliminates the outlet and the device cord (patch cord), adding a new concept and connection method referred to as “direct connections” (Direct Connections) or Modular Plug (MPTL) terminated link (TIA 568 2.D).
FACT: It is clarified that the use of MPTL systems are designed for low management equipment such as cameras, access controls, AP among others. For these devices, it is possible to connect directly via a patch cord from an ONT to the final device without the risk that the MPTL does not work properly since this field connector must be used carefully because it does not fit properly in certain equipment models such as cameras and AP. Additionally, in the case that the MPTL is required, it is indifferent in traditional systems such as POL.
MYTH: POL requires several elements to connect the devices (e.g., PoE security cameras): Camera + patch cord + ONT + electrical outlet. What is the cost of this installation and its administration?
FACT: It is clear that POL systems at ONT level require an electrical outlet for its operation, but it is not an inconvenience in the matter of costs, usually the workstations have a standard power supply as regulated where it can easily be connected these devices and in any case derive a small section of the nearby circuit to take a power outlet. According to TCO exercises, making the objective comparison between systems (POL and conventional LAN NETWORK) savings have been registered at CAPEX and OPEX level under the solution of passive optical networks.
MYTH: GPON networks have been used for more than 10 years. This technology makes administration in an internal plant network difficult by delegating its responsibility to passive components.
FACT: On the contrary, the administration of the network is easier once the management is centralized, that is, they are carried out in the main active equipment called OLT where all access devices (ONT) are controlled. Ethernet networks have been used since the 1980s.
MYTH: The methods used to determine network speeds are based on statistical methods, and do not harmonize with the technologies available by the IEEE.
FACT: On the contrary, Statistical methods are ideal tools for the adequate sizing of the performance of a network avoiding the underutilization of resources and excessive oversizing affecting the budget of the final client.
MYTH: Complicated administration of maximum speeds and losses of fiber and connectors. You must validate how much is the maximum loss in decibels to control.
FACT: The optical budget is always important to analyze and fulfill it in any optical solution including in the optical systems of a Datacenter, it is a normal mechanism and does not generate any disadvantages. Additionally, the OLTs have in their software reception power measurement to verify and control the appropriate levels of power that the active part must receive, and its verification is quite simple.
MYTH: A POL infrastructure is difficult to manage, high risk, inefficient and not very aesthetic.
FACT: On the contrary, due to their compliance with the norm, these systems are fully manageable at the passive level. Regarding active levels it is much more efficient in terms of configuration of distribution devices as access since a concept of centralized management is used since ONTs are very low administration devices, that is, once installed we no longer need to interact directly with them, in the opposite case of the different layers of switches that generate multiple management points generating greater man hours in terms of configuration. Regarding aesthetics, this will depend on the quality of the workforce and the installer and not on the solution, in traditional schemes wiring centers have been seen that are attentive to the aesthetics or on arrival to the end-user.
MYTH: Inspection Points. Designers and consultants must add inspection points to their plans including the metal box to house each ONT. This is expensive in construction processes.
FACT: According to TCO exercises, making the objective comparison between systems (POL and conventional LAN NETWORK), savings have been recorded at the CAPEX and OPEX level under the solution of passive optical networks. In addition, not all ONTs are going to be hosted at these sites, in addition to a conventional LAN network, inspection records must also be left to lay new cables. Another important factor is that many Enterprise architectures, the concept of infrastructure in sight (i.e. without ceiling) is being used, so it should not be a problem either.
MYTH: Management software. The administration tool does not show the actual physical connection channel for proper dialing and administration.
FACT: AIM systems are normally focused on datacenters markets where high cable density levels are required to be managed following ITIL guidelines. There must be clear procedures to take full advantage of these solutions, it has been shown that many customers underutilize these types of solutions and finally do not end up using them. In POL systems, dialing schemes are managed in compliance with standards and additionally, management can be done from monitoring software tools to control the traffic and the assignment of services to each of the end users as an assignment of descriptors to map and identify the network properly for troubleshooting or troubleshooting procedures.
MYTH: Total consumption monitoring and administration of “energy consumption savings”. Management tools do not deliver results of the “savings offered” by the companies that drive this technology. On the other hand, the analyzes provided by the suppliers intend to ignore the energy consumption of the ONTs whose average consumption is 18.5 Watts, which represents in a project where around 500 ONTs are installed a total consumption only in the ONTs of 9.2 Kva (18.5 Watts x 500 ONTs).
FACT: On the contrary, none of the manufacturers of POL do not know the consumption of the ONT because it is clear that the loads are distributed in the work areas and these are taken into account in the calculations of electrical system load, on the other hand makes the clarification that the typical ONT does not consume 18.5 watts but less than 8 watts, therefore the analysis does not proceed, in conclusion the consumption of active equipment of a traditional network versus POL is similar, the difference is that in PON technologies LAN cooling requirements are reduced in technical rooms generating energy consumption savings than this if it is measurable through monitoring software.
MYTH: Impossibility of delivering real speeds of 1Gbps, 2.5 Gbps, 5Gbps, 10Gbps to users. Users indicate that their devices work at a maximum of 1Gbps. The way they identify it is by entering the computer software that shows that the connection is probably at 1Gbps. What should be used in a network traffic analyzer (sniffer) to determine the actual speed and bandwidth delivered by device and / or user.
FACT: There is a gap in the conception of the bandwidths demanded by user applications where the calculations made by manufacturers to determine the capabilities of Uplink are quite oversized in a LAN network, where:
- It is assumed that users are going to demand 1Gbps of bandwidth, the reality is that the applications of a typical corporate workplace will not require more than 5 Mbps. (See table tables of consumption of corporate applications-BICSI), You can additionally check the user equipment through the task manager where there is a tool to verify the consumption of network services, moreover, operator networks and home users demand much more bandwidth than a workstation of a company.
- User Windows operating systems do not allow work at more than 600 Mbps.
- Uplink sizing using oversubscription techniques is oversized and assumes maximum consumption of 1 Gbps. The manufacturer of switches can justify to support applications and greater bandwidths in the future, but they are forcing to change the equipment of switches to a span of 5 to 10 years for a subject of programmed obsolete. 25 years have passed, and the consumption of typical desktop and CCTV applications have not yet been able to pass the 10 Mbps barrier.
- It can be demonstrated with facts using bandwidth consumption analyzers such as Cacti, PRTG, and others, how much uplink switches are really demanding, where they will not reach 10G. There are cases of large universities where they are working their network with a 1 Gbps access switch uplink and there are no problems at all.
Regarding GPON systems, it effectively uses the use of bandwidths, avoiding oversizing the systems. It also manages a concept called statistical multiplexing where it intelligently allocates greater bandwidth to the application that needs it in an instant of time from idle users, in addition to handling more real oversubscription concepts through the use of an intelligent algorithm called dBA (dynamic bandwidth allocation) where he modifies the bandwidth widths according to what the application requires depending on the time. Additionally, passive optical network systems in the future will migrate to 10G technologies when the applications or services become more demanding.
On the other hand, in case of requiring more bandwidth in the future, equipment with XG-PON or NG-PON2 technology can be used to increase the traffic capacity towards users.
MYTH: Field tests and certification. The companies that install these technologies certify the network with traditional fiber optic networks certifiers, not knowing that special devices must be used to certify PON. They do not regularly know which device the certification was made with.
FACT: PON systems do not require special instrumentation to certify the Optical Channel. you can even use fiber bolsters with Power Meter function for existing certifiers or use conventional Power Meter with VFL.
MYTH: The transmission and reception bandwidth are different. 2.5 Gbps from the OLT-ONT and 1.25 Gbps from the ONT-OLT. This throughput does not deliver 1Gbps to a user and is not enough to support 10Gbps.
FACT: Typical corporate users require nowadays from 1 to 7 Mbps (see table below). Telephony is in order of 150 Kbps, a high definition camera 6 Mbps, video game consoles that process 3D images and multiplayer accesses do not require more than 15 Mbps. Gartner studies state that the typical consumption for corporate applications are the ones evidenced in the following table:
It is also important to add that with the advent of Cloud computing, North-South communication is increasingly gaining space if compared to point-to-point communications.
MYTH: Trained staff? It is difficult for a user to achieve personal knowledge of these technologies implemented inside buildings. This added to the low level of support delivered to the user. Generally, the supports are delivered by personnel outside the country in their own schedules.
FACT: Recognized manufacturers have LOCAL training programs in the design, implementation and commissioning of both active and passive POL technology. Several integration channels are accredited to provide first level support, in addition to support through its authorized service center (CSA), you can exercise local support. Additionally, the final customer is trained in the configuration and management of the platform.
MYTH: Losses and damages of ONTs. The ONTs are installed on the roofs to avoid security problems, increasing the problems of administration, identification, monitoring of the circuits and troubleshooting, increasing the administration costs. It is important to collect information and its corresponding analysis of the percentage of failures that ONTs have. If this percentage is 10% (50 ONTs in a 500 ONT installation), this can alter the availability of the network at critical points in a hospital. The replacement of these devices is the responsibility of the supplier until the warranty period (approx. 2 to 3 years). Once the warranty is over, the user is responsible for the replacement of the ONTs. How much is each ONT worth and how about its replacement?
FACT: It is important to clarify that the ONT are low management devices and do not require any complex management process so everything is configured from the OLT therefore there is no problem of identification, monitoring etc., there have been evidenced experiences of hosting ONT at heights of more than 10 meters and at no time, even after two years of operation in relevant projects in the POL market, it has NOT been necessary to change or manage such equipment. Conventional LAN switchgear systems handle the same guarantee schemes between 2 and 3 years and in case of failure, it is more expensive to lose 24 or 48 users than only 4 in the access layer.
MYTH: Devices that are regularly used with PoE. Each ONT must be fitted with a regulated outlet on the ceiling to provide PoE to the devices. This makes it impossible to get the most out of what is really expected with PoE which is to eliminate the electrical wiring for devices that require PoE and additionally PON does not support the latest PoE technologies of 60W, 90W, 100W required in the world IoT).
FACT: POL technologies have conceptualized PoE ++ support through the ONTs that connect the end user devices. Additionally, in the POL market, fiber optic cables are available with conductors for power supply of the ONT (remote powering), therefore, additional electrical wiring is eliminated in the system.
MYTH: Security. With PON technology the cameras would be connected to the ONTs placed on the roofs but with the percentage of failures that may occur from the ONTs it is preferable to use a parallel network of Cat 6A minimum shielded copper cable for this independent of the PON system. You cannot leave a system as demanding as the security network with 100% unreliable devices. PON security is not recommended at this scenario. The risk is high.
FACT: It is clarified that PON systems are highly robust to connect devices such as security cameras among others, there have been cases in projects where ONTs are installed at 10 meters high supporting CCTV and WIFI systems working for more than two years without problems, in addition there is a greater risk of damaging a 24 or 48 port switch that is connecting most of the cameras, the impact is much greater than losing an ONT with only 4 cameras. It is recalled that OLTs are “Carrier Class” equipment designed for continuous work thanks to their high levels of reliability compared to traditional Switching systems, it also allows to manage redundancy schemes for high availability.
MYTH: Adding users. If there are no free ports of an ONT, you should look for availability in nearby ONTs by generating a “cable mix” on the roofs. Otherwise, a new splitter with a new fiber must be installed from the OLT causing traumas in the initial wiring design and its corresponding administration. This additional to the losses in decibels that are generated and that must be contemplated. Administrators suffer from tools to control this, which causes this type of monitoring not to be carried out (see next point).
FACT: It is clarified that in any network design, one of the factors to be analyzed is the issue of scalability or growth, GPON systems also include this concept in leaving optical ports available at first level distributors located in the field, in addition to the same It happens in traditional topologies where rack spaces, duct sizes and pipes etc. are not properly sized, which in the end becomes chaos, therefore this factor depends on the quality of the design and not on the solution. Regarding decibel losses, as an added value, POL systems use BLI technology fibers that are insensitive to radii of curvature, generating high tolerances for demanding installation procedures without affecting the insertion losses measured in dB.
MYTH: Analysis and control of signal strength and loss in decibels if extra users and / or devices such as a splitter are required. Neither users nor administrators regularly carry out this control and monitoring or do power management or decibel losses of fiber connections to users. PON has a limit of losses in a channel that must be controlled.
FACT: On the contrary, the POL systems using the software that has the active layer allows the monitoring of the optical power levels of the network quickly, additionally there are notification systems in case of registering any failure in the link that can be deploy via SNMP to monitoring software generating alerts to the administrator. It has been calculated that the levels of insertion losses depending on the laser to be used can reach up to 32dB at 20 km, something that copper wiring systems (100-meter channel limit) cannot achieve in a conventional installation.
MYTH: Traffic profiles to specific users. The administration tools do not allow in a friendly way to carry out this work, which makes complicated an administration where movements, additions and changes are made, especially with medical equipment that require minimum levels of connectivity.
FACT: On the contrary, monitoring software and other tools are available to make a friendly administration since POL equipment handles protocols such as SNMP.
MYTH: Dynamic discovery of devices. It is not done in PON. What is done is the knowledge through the OLT port that ONTs are connected. There is NO circuit tracking.
FACT: On the contrary, PON systems allow to easily detect the devices that are connected in the ONT ports, additionally they have open protocols like the cisco CDP that in case of POL is the LLDP to detect and discover the devices that are connected.
MYTH: Regularly support and troubleshooting are delivered by the manufacturer from their parent companies. There is no problem resolution with expert staff locally.
FACT: The most recognized Manufacturers in the POL market, has accredited channels of POL technology with the ability to design, implement and put the solution into service locally.
FACT: It is clarified that POL systems perfectly manage redundancy schemes in GPON ports of the OLT, there are splitters with double input to guarantee redundancy in the distribution layer, with respect to the uplink ports that the OLT has, you can handle schemes trouble-free redundancy and the use of spanning tree mechanisms in all its versions to avoid switching loops in the ethernet layer.
MYTH: Some problems that arise are not solved locally but regularly by the manufacturer remotely. High risk: Will the response be immediate and timely?
FACT: The manufacturers of the most recognized POL solutions, normally train the personnel of the entire value chain, from the client network administrator to the integrator that provides first level support, therefore the answers are IMMEDIATE AND TIMELY.
MYTH: Category 6A copper wiring link supports the future adoption of remote power technology (e.g., Ethernet or PoE power) and 10GBASE-T transmission speeds with the minimum need to upgrade or replace the existing equipment.
FACT: It is clarified that traditional technologies based on SI switches must replace active equipment such as the migration from fast ethernet to giga ethernet or towards 10GBaseT in a typical period of 5 years. POL solutions handle single-mode fiber optic with capabilities superior to cat 6A cabling and longer-range distances. Regarding PoE, POL networks have ONT equipment with PoE ports.
MYTH: Use POL solutions if your users require low speed and long-distance support. But do you know what speed or services your users require in the coming years?
FACT: On the contrary, use POL solutions for any type of network, especially medium and large, that require high demand in the traffic of information seeking to generate considerable savings in the TCO and without oversizing the resources normally generated by traditional technologies.
MYTH: If your company handles a lot of information in the cloud and your users consult the WEB and do not share robust information (e.g. video, Real-time images between offices and / or surgery rooms or devices), you should probably be more concerned about the speed of the WAN than the LAN for its users and speeds of less than 100 Mbps may be sufficient.
FACT: Today, all IT services are being migrated to the cloud in most of the verticals that are known, even in the health sector, information must be sent even to the cloud in order to generate diagnostic reports from other clinics or review of other specialists and therefore have to access the WAN.
MYTH: Contingency process when there is a problem in the network. Companies choose to increase their investment and create a redundancy system by acquiring double Core Switch and double OLT. They generally do not have redundancy in splitters or ONTs which reinforces the placement of the security system by traditional structured cabling and not by the PON structure. On the other hand, in the PON technology, the activation of redundant connections cannot be performed, therefore robust protocols such as Spanning tree cannot be used to allow interconnection devices to automatically enable or disable redundant connection links.
MYTH: If speed, security, redundancy, implementation of new medical devices, easy administration are not critical factors in the network, this POL solution is more economical.
FACT: On the contrary, the use of POL solutions would be recommended due to the high levels of reliability, SECURITY, REDUNDANCY in user operations that are critical as explained in previous paragraphs.
MYTH: GPON technology is said to work at up to 1 Gbps. By comparison, Gigabit Ethernet technology can evolve to support 10Gbps and 40Gbps rates.
FACT: PON technology works with the GPON protocol and its evolutions, the XG PON and XGS PON, working at rates of 10G or its future implementations expected to reach 40, 100 and up to 400 Gbps thanks to the use of WDM technology. The following are the ITU-T standards and their transmission rates:
- GPON (ITU-T G.984): 2.5 Gbps Downstream / 1.25 Gbps Upstream
- XG-PON (ITU-T G.987): 10 Gbps Downstream / 2.5 Gbps Upstream
- XGS-PON (ITU-T G.9807.1): 10 Gbps Downstream / 10 Gbps Upstream
- NG-PON 2 (ITU-T G.989): 40 Gbps Downstream / 10 Gbps Upstream 100Gbps (in study)
MYTH: PON networks can have insertion losses of up to 0.5 dB making them less secure than Gigabit Ethernet networks.
FACT: Optical passive networks technologies manage high levels of security:
- At the physical level: Optical fiber is immune to electromagnetic fields generated in the medium that can cause information loss. In addition, information cannot be captured by physically intercepting a fiber in the same way as it is possible with copper media.
- At the logical level: GPON systems work natively and by default with AES 128 encryption. In addition, it is possible to implement all Ethernet protocols and functionality such as Access Control Lists (ACL), Port Security and 802.1X. As a reference, support for such features can be found in the OLT LW3008C and G2500 User’s Guide available at www.furukawalatam.com.
MYTH: The GPON physical network is a hub that multiplexes the traffic flow creating reliability and performance difficulties in services that require real time transmission such as voice and video. In contrast, Ethernet works on a three-tier architecture, end devices connected to one access switch can communicate with another without the packet having to travel across the network, which is important for real-time communications.
FACT: GPON networks are composed of only two layers of active equipment, which considerably reduces latency compared to multi-layer Ethernet networks (core, distribution, and access). Additionally, it should not be confused that the Optical Splitter is a Hub since it is a passive device that simply splits the optical signal into N number of channels. At the logical level, both OLTs and ONTs allow traffic segmentation in VLANs and their various applications (VLAN Tagging, VLAN Stacking-in-Q, VLAN Translation, dot1Q, 802.1D, among others), a characteristic of Switch systems. Regarding services, the GPON platform can manage different levels of QoS (Quality of Service) to prioritize traffic such as voice, video and others. They also enable intelligent bandwidth management (DBA algorithm). GPON networks are designed to offer multiservice systems (voice, data and video) and real-time applications. There are numerous deployments in the Enterprise and TELCO carrier environment around the world.
MYTH: It consolidates two levels into one by decreasing controls for redundancy. In contrast, ethernet supports the Spanning Tree protocol.
FACT: GPON systems support different redundancy schemes like a conventional network as it is listed in ITU-T 984. In addition, OLT can protect ONT level switching loops and support for spanning tree protocols. Rapid Spanning tree and MSTP at the OLT port level.
MYTH: In GPON, increasing availability and reliability to a hub requires redundant equipment, adding costs to the system.
FACT: Regarding availability and reliability, it is clarified that GPON devices support a reliability level of 5 nines (99.999%), higher than traditional switch systems, and have various redundancy schemes to ensure operation to be continued. With respect to PoE applications, GPOL systems handle ONT equipment with PoE and Poe + features to power the different equipment you require such as AP, Cameras, telephones between others. WLAN Integration can be handled perfectly because ONTs have access LANs to connect to WLAN antennas. For monitoring, GPON has the OMCI protocol (ONT management layer 2) and SNMP (for OLT administration), where an NMS can perform alarm monitoring, diagnostics, etc. And lastly referring to QoS, as mentioned before, GPON platform handles different levels of Service (QoS) to prioritize traffic as the case of voice and other services, but also to manage smart bandwidth management.
MYTH: GPON systems obey a two (2) layer model instead Gigabit Ethernet manages a 2 or 3-layer model generating more reliability by developing high application performance and real-time support and the best type of traffic.
FACT: On the contrary, having a two-layer model considerably improves network latency and points of failure, however, switched networks by using multilayer models between computers will generate higher levels of network latency and points of failure. Additionally, if spoken in terms of the OSI model, GPON systems handle Layer 2 and 3 functionalities as protocols related to segmentation through VLANs or the management of routing protocols, whether static or dynamic. Having an architecture of less layers, will facilitate the administration and operation of the network, since everything is managed from a centralized team.
Regarding GPON systems, it effectively uses the use of bandwidths, avoiding oversizing the systems. It also manages a concept called statistical multiplexing where it intelligently allocates greater bandwidth to the application that needs it in an instant of time from idle users, in addition to handling more real oversubscription concepts through the use of an intelligent algorithm called dBA (dynamic bandwidth allocation) where he modifies the bandwidth widths according to what the application requires depending on the time. Additionally, and considering another reality cited in this document, the passive optical network systems in the future will migrate to 10 G technologies when the applications or services begin to be more demanding.
On the other hand, in case of requiring more bandwidth in the future, equipment with XG-PON or NG-PON2 technology can be used to increase the traffic capacity towards users.
MYTH: The bandwidth is shared by Splitter instead in Gigabit Ethernet network bandwidth is dedicated to each network device.
FACT: The bandwidth does not depend on the optical division in GPON systems but the number of ONTs that are connected to the medium, it is clear that the multipoint point topology is shared bandwidth but it should also be clarified that Gigabit Ethernet systems Conventional also, it is not true that they have bandwidth dedicated to the access port because they will depend on the capacity of Uplink that the Switch has, for example if we assume a 1: 1 over subscription for a 1G uplink on a switch of 48 Ethernet ports, the bandwidth will be divided by 48, that is to say, there would be an available or not available bandwidth of 20 Mbps assigned to the user. In addition, GPON systems can increase bandwidths for certain critical applications simply by reducing the number of ONT to access the 2.5G channel in the worst case, even bandwidths are greater than theoretically calculated due to multiplexing statistics and the use of the DBA algorithm (dynamic Bandwidth allocation).
MYTH: The physical network is a hub. There are no switches in the logical distribution or ODN, only passive elements. All traffic is forced to travel between ONT-OLT while gigabit Ethernet solutions are switched.
FACT: On the contrary, this characteristic of the OLT and the splitter assuming the function of the distribution and aggregation layer avoids high levels of latency, instead when handling a multilayer model as in traditional Switch technology, the more active equipment added in the middle the higher level of latency will have and also they generate more points of failure and difficulty of troubleshooting or solving problems quickly.
MYTH: GPON solutions do not offer speed mixing. Each user receives the same bandwidth regardless of their need, instead the speeds can be mixed in an Ethernet network, optimizing the performance of a user’s applications or needs.
FACT: An FTTH operator network can be taken as an example, if GPON systems could not manage bandwidth it would be impossible to assign service levels (SLA) to users, that is, they could not sell packages of 10 or 20 Mbps to users in case the myth was correct. On a technical level, the downstream BW can be controlled by means of limited rate functions and the upload widths through the use of the DBA through the Status Report functions where the ONT constantly informs the OLT of the bandwidth requirements that have a certain application and the OLT will perform a reconfiguration of the bandwidth according to the need. This is one of the main advantages of a GPON system. Each ONT is associated with a profile that indicates the transmission speed of downstream and upstream.
MYTH: GPON systems are weak in Troubleshooting Tools. Gigabit Ethernet has packet tagging for video quality and diagnostic service and troubleshooting (wireshark), 802.1X security services, power monitoring and control.
FACT: On the contrary, GPON systems have enough diagnostic tools either by CLI or GUI interfaces where the main ones are indicated:
- It has syslog functions
- It has mirroring ports that will allow monitoring via network sniffering tools.
- RMON and SNMP
- Diagnostic commands for optical power levels that reach the ONT
- 802.1X port security functionalities among many more.
MYTH: In GPON systems, there is no centralized power backup from the communications room to POL devices and the entire network may fall.
FACT: Each POL device, such as OLTs, has a double redundant source to be supported by different AC circuits generated by independent UPS, maintaining a high level of power availability. The ONT, especially PoE systems have a main port for AC power connection through an adapter, also has a BBU port that allows to connect a small battery bank to generate redundancy in case the main source fails. The centralized backrests can be worked both in DC using rectifiers or through UPS in the case of AC power.
MYTH: Many points of failure. A splitter can take out all the ONT that it has connected.
FACT: A splitter is a passive device where it does not involve any electronics or power source that are normally points of failure, the probability of damage is too low compared to the active part of the switches. Even switches are more likely to fail because they have low MTBF compared to GPON devices.
MYTH: Each OLT is a point of failure, if one falls the total network can fall.
FACT: The same happens with the distribution and Core switches, if they fail, the network also collapses, for that in both systems there are different levels of redundancy to guarantee high availability, it is also remembered that OLTs usually have double redundant sources, the switches some ranges do not have this functionality, in addition the OLT handle levels of reliability of 5 nines (99.999%).
MYTH: GPON solutions do not work with video communications services, collaboration, WLAN interaction, desktop virtualization, mobile, cloud, unified communications.
FACT: On the contrary, because OLT and ONT devices handle Layer 2 and 3, QoS Quality of Service normally used in Ethernet technology, they can perfectly handle all these services indicated since they speak IP, it can even handle IPTV through protocols such as IGMP and multicast without problem Additionally, it can integrate “NO IP” services such as the CATV that uses analog RF signals where they are opticalized and sent over the same Fiber infrastructure, making GPON the platform with the highest convergence than a conventional Gigabit Ethernet system.
MYTH: Hard to run Updates
FACT: On the contrary, at the physical infrastructure level, the ODN network can support different PON technologies such as XGPON simply by upgrading the active part. Regarding Firmware updates it is much easier and faster than a conventional solution, with a single command you can update the images of X number of ONT the same for OLT.
MYTH: GPON uses the TDMA (Time Division Multiple Access) communication scheme, accessing each OLT every 125 us vs. 2 Tbps of switches switch capacity.
FACT: The GPON systems in its upstream effectively handle TDMA, generating a collision-free environment, mounting different packages in 125 us temporary slots. There is no relation of the comparison between the Upstream transmission mode versus the backplane capacity of the switches.
MYTH: For TV they use EDFA amplifiers, which are very expensive.
FACT: For Video overlay services (send video using RF signals over fiber optics) it is clear that new hardware such as the optical transmitter, such as the amplifier and its associated costs must be contemplated. The most advisable thing is to compare this solution with IPTV systems that include the headers that the client must quote and make the price comparison to select the most appropriate type of technology. However, the POL solution can handle both technologies without problems. The cost of additional devices for Video RF Overlay will depend on the magnitude of the project.
MYTH: PON involves a wiring and regulated regulated electrical system within costs
FACT: The switches of a wiring center also require circuits regulated by UPS and their consumption must also be considered of the load boxes. In PON too. All the infrastructure involved with the implementation of wiring centers already mentioned in this document must be taken into account, also take into account the investment returns that a shopping center could have, for example in dispensing with these spaces for other uses such as ATM installation automatic generating an interesting benefit to the final customer.